FSBEI HPE "Chuvash State Agricultural Academy"

Department of Infectious and Invasive Diseases

On the topic of:
Microbiology of feed.

Completed by a 2nd year student
agronomic faculty
2nd group 3rd subgroup
Egorov M.N.
Checked by: Tikhonova G.P.

Cheboksary 2013
Content:
* PROCESSES OCCURRING WHEN DRYING HAY AND OTHER FEEDS
* PRESERVATION OF FEED

Drying is the most common way of preserving green mass and other forage. Drying of hay is carried out in different ways - in swaths, rolls, in heaps, on hangers, etc. Even in dry weather and fast drying, some losses nutrients in the feed are inevitable, since respiration and other enzymatic processes continue to take place in the plant mass. In the case of more or less prolonged drying, the role of the processes noted increases greatly, and this, in turn, leads to an increase in losses, which are largely associated with microorganisms multiplying on a moist plant mass. To limit the loss of nutrients, they tend to use artificial drying of hay, using forced ventilation with atmospheric or heated air.

When drying feed, the number of vital microorganisms in them gradually decreases. Nevertheless, on a good-quality food of plant origin, you can always find more or less microbial cells characteristic of the epiphytic microflora, as well as other microorganisms that get here from the soil and air. They are in anabiotic state.

When the stored feed is moistened, microbiological processes begin to rapidly develop in it, and at the same time the temperature rises. This phenomenon, called self-heating (thermogenesis), is associated with the vital activity of microflora.

Microorganisms use for synthetic purposes no more than 5-10% of the energy of nutrients consumed by them. The rest of the energy is released into the environment mainly in the form of heat. Thus, thermogenesis depends mainly on the incomplete utilization of energy by microorganisms released during their biochemical processes.

The phenomenon of thermogenesis becomes tangible only under conditions of hindered heat transfer. Otherwise, heat is dissipated from the environment where microorganisms multiply, without noticeable warming up of the substrate. Therefore, in practice, only significant accumulations of various materials are warmed up, that is, such masses in which heat accumulation can occur.

With self-heating of the plant mass, a clearly pronounced change in microflora is observed. First, mesophilic microorganisms multiply in the warming mass. With an increase in temperature, they are replaced by thermophiles, which contribute to an increase in the temperature of organic substances, since they have an exceptional rate of reproduction.

Strong heating of a sufficiently dry and porous mass can cause its charring and the formation of flammable gases - methane and hydrogen, which are adsorbed on the porous surface of charred plant particles, as a result of which spontaneous combustion can occur. It is highly probable that iron compounds play the role of catalyst during ignition. Ignition occurs only in the presence of air and only if the mass is not sufficiently compacted. In windy weather, spontaneous combustion is more frequent.

Thermogenesis causes significant harm. It causes spoilage of the hay. However, with moderate self-heating, thermogenesis may be desirable. For example, "self-matured" straw as a result of heating is better eaten by livestock, etc. The phenomenon of thermogenesis is used to prepare the so-called brown hay. It is prepared in areas where, due to climatic conditions, it is difficult to dry hay ...

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Microflora of feed and food

Completed by a 2nd year student

Tutunar Denis

Microflora of feed

Epiphytic microflora... A varied microflora, called epiphytic, is constantly present on the surface parts of plants. On stems, leaves, flowers, fruits, the following non-spore types of microorganisms are most often found: Bact, herbicola makes up 40% of all epiphytic microflora, Ps. fluorescens - 40%, lactic acid bacteria - 10%, the like - 2%, yeast, molds, cellulose, butyric acid, thermophilic bacteria - 8%.

After mowing and loss of plant resistance, as well as due to mechanical damage to their tissues, epiphytic and, first of all, putrefactive microflora, multiplying intensively, penetrates into the thickness of plant tissues and causes their decomposition. That is why crop production (grain, coarse and succulent fodder) is protected from the destructive effect of epiphytic microflora by various conservation methods.

It is known that plants have bound water, which is part of their chemical substances, and free water, which is drip-liquid. Microorganisms can multiply in the plant mass only if there is free water in it. One of the most common and affordable methods for removing free water from crop products and therefore preserving them is drying and ensiling.

Drying grain and hay provides for the removal of free water from them. Therefore, microorganisms cannot multiply on them as long as these products are dry.

Freshly cut, unstable grass contains 70 - 80% water, dried hay only 12-16%, the remaining moisture is bound with organic substances and microorganisms and is not used. During the drying of hay, about 10% of organic matter is lost, mainly during the decomposition of proteins and sugars. Especially large losses of nutrients, vitamins and mineral compounds occur in dried hay in swaths (windrows) when it rains frequently. Distilled rain water washes them up to 50%. Significant losses of dry matter occur in the grain during its self-heating. This process is due to thermogenesis, that is, the creation of heat by microorganisms. It arises because thermophilic bacteria use for their life only 5-10% of the energy of the nutrients they consume, and the rest is released into their environment - grain, hay.

Silage of fodder. When growing forage crops (corn, sorghum, etc.) from one hectare, it is possible to obtain significantly more feed units in green mass than in grain. In terms of starch equivalent, the nutritional value of green mass during drying can be reduced to 50%, and during ensiling only up to 20%. When ensiling, small leaves of plants with a high nutritional value are not lost, and when dried, they fall off. Silage can also be placed in variable weather. Good silage is a succulent, vitamin, milk-producing forage.

The essence of ensiling lies in the fact that lactic acid microbes that decompose sugars with the formation of lactic acid, accumulating up to 1.5-2.5% of the silage weight, intensively multiply in the crushed green mass laid in the container. At the same time, acetic acid bacteria multiply, converting alcohol and other carbohydrates into acetic acid; it accumulates 0.4-0.6% of the silage mass. Lactic and acetic acids are a strong poison for putrefactive microbes, so their reproduction stops.

Silage remains in good condition for up to three years, as long as it contains at least 2% lactic and acetic acids, and the pH is 4-4.2. If the reproduction of lactic acid and acetic bacteria weakens, then the concentration of acids decreases. At this time, yeast, molds, butyric acid and putrefactive bacteria begin to multiply at the same time, and the silage deteriorates. Thus, obtaining good silage depends primarily on the presence of sucrose in the green mass and the intensity of the development of lactic acid bacteria.

In the process of silage maturation, three microbiological phases are distinguished, characterized by a specific species composition of microflora.

The first phase is characterized by the multiplication of mixed microflora with some predominance of putrefactive aerobic non-spore bacteria - Escherichia coli, Pseudomonas, lactic acid microbes, yeast. Spore-bearing putrefactive and butyric acid bacteria multiply slowly and do not prevail over lactic acid bacteria. The main medium for the development of mixed microflora at this stage is plant sap, which is released from plant tissues and fills the space between the crushed plant mass. This contributes to the creation of anaerobic conditions in the silage, which inhibits the development of putrefactive bacteria and favors the reproduction of lactic acid microbes. The first phase with dense storage of silage, that is, under anaerobic conditions, lasts only 1-3 days, with loose storage under aerobic conditions, it is longer and lasts 1-2 weeks. During this time, the silage is heated by intensive aerobic microbiological processes. The second phase of silage maturation is characterized by rapid multiplication of lactic acid microbes, and at first, predominantly coccal forms develop, which are then replaced by lactic acid bacteria.

Due to the accumulation of lactic acid, the development of all putrefactive and butyric acid microorganisms stops, while their vegetative forms die, only spore-bearing ones remain (in the form of spores). With full observance of the technology of silage in this phase, homofermentative lactic acid bacteria multiply, forming only lactic acid from sugars. In case of violation of the technology of silage filling, when in it. contains air, the microflora of heteroenzymatic fermentation develops, resulting in the formation of unwanted volatile acids - butyric, acetic, etc. The duration of the second phase is from two weeks to three months.

The third phase is characterized by the gradual death of lactic acid microbes in the silage due to the high concentration of lactic acid (2.5%). At this time, the ripening of the silage is completed, a conditional indicator of its suitability for feeding is the acidity of the silage mass, which decreases to pH 4.2 - 4.5 (Fig. 37). Under aerobic conditions, mold and yeast begin to multiply, which break down lactic acid, butyric acid and putrefactive bacteria germinating from the spores use this, as a result the silage becomes moldy and rotten.

Silage defects of microbial origin... Failure to comply with the proper conditions for laying and storing the silage will cause certain defects.

Decay of silage, accompanied by significant self-heating, is noted when it is loosely laid and insufficiently compacted. The rapid development of putrefactive and thermophilic microbes is facilitated by the air in the silo. As a result of protein decomposition, silage acquires a putrid, ammonia smell and becomes unsuitable for feeding. Decay of silage occurs in the first microbiological phase, when the development of lactic acid microbes and the accumulation of lactic acid, suppressing putrefactive bacteria, are delayed. To stop the development of the latter, it is necessary to lower the pH in the silage to 4.2-4.5. The rotting of the silage is caused by Er. herbicola, E. coli, Ps. aerogenes. P. vulgaris, B. subtilis, Ps. fluorescens as well as molds.

Rancidity of silage is caused by the accumulation of butyric acid in it, which has a sharp bitter taste and an unpleasant odor. In a good silage, butyric acid is absent, in a silage of average quality it is found up to 0.2%, and in an unsuitable for feeding - up to 1%.

The causative agents of butyric acid fermentation are capable of converting lactic acid into butyric acid, as well as causing putrefactive decomposition of proteins, which aggravates their negative effect on the quality of silage. Butyric acid fermentation is manifested with the slow development of lactic acid bacteria and insufficient accumulation of lactic acid, at a pH above 4.7. With the rapid accumulation of lactic acid in the silage up to 2% and pH 4-4.2, butyric acid fermentation does not occur.

The main causative agents of butyric acid fermentation in silage: Ps. fluo-rescens, Cl. pasteurianum, Cl. felsineum.

Peroxidation of silage is observed during vigorous reproduction of acetic acid, as well as putrefactive bacteria capable of producing acetic acid. Acetic acid bacteria multiply especially intensively in the presence of ethyl alcohol in the silage, accumulated by alcoholic fermentation yeast. Yeast and acetic acid bacteria are aerobes; therefore, a significant content of acetic acid in the silage and, consequently, its peroxidation is noted in the presence of air in the silo.

Silage mold occurs when there is air in the silo, which favors the intensive development of mold and yeast. These microorganisms are always found on plants, therefore, under favorable conditions, their rapid reproduction begins.

Rhizosphere and epiphytic microflora can play a negative role as well. Root crops are often affected by rot (black - Alternaria radicina, gray - Botrutus cinirea, potato - Phitophtora infenstans). Excessive activity of butyric acid fermentation pathogens leads to spoilage of silage. On vegetative plants, ergot (claviceps purpurae) reproduce, causing the disease ergotism. Mushrooms cause toxicosis. The causative agent of botulism (Cl. Votulinum), getting into the feed with soil and feces, causes severe toxicosis, often fatal. Many fungi (Aspergillus, Penicillum, Mucor, Fusarium, Stachybotrus) colonize food, multiplying under favorable conditions, and cause acute or chronic toxicosis in animals, often accompanied by nonspecific symptoms.

Microbiological preparations are used in the diets of animals and birds. Enzymes improve the absorption of feed. Vitamins and amino acids are obtained on a microbiological basis. Use of bacterial protein is possible. Fodder yeast is a good protein and vitamin feed. Yeast contains an easily digestible protein, provitamin D (zgosterol), as well as vitamins A, B, E. Yeast multiplies very quickly, therefore, in industrial conditions, it is possible to obtain a large amount of yeast mass when cultivated on molasses or saccharified fiber. At present, in our country, dry feed yeast is prepared in large quantities. For their manufacture, a culture of feed yeast is used.

Microflora of food products during cold storage

The microflora of raw food products of plant and animal origin is very diverse. The microorganisms that make up the microflora of products include bacteria, yeast, molds, protozoa and some algae. Microorganisms in nature are widespread due to their easy adaptation to heat, cold, lack of moisture, as well as due to their high resistance and rapid reproduction. silage microbial microflora mold

The development of microbiological processes in food can lead to a decrease in nutritional value and sharply worsen the organoleptic characteristics of food products, cause the formation of substances harmful to the products. Therefore, one of the tasks of the food industry is to limit the harmful effects of microorganisms on food. However, there are certain microorganisms, the presence of which in food products gives them new flavoring properties. The method of replacing unwanted microflora with microflora with the required properties is used in the production of kefir, yogurt, acidophilus, cheeses, sauerkraut, etc.

For the development of microorganisms, it is necessary to have water in a form accessible to them. The need of microorganisms for water can be expressed quantitatively in the form of water activity, which depends on the concentration of solutes and the degree of their dissociation.

The development of microflora with a decrease in temperature is sharply inhibited, and the more, the closer the temperature is to the freezing point of the tissue fluid of the product. The effect of a decrease in temperature on a microbial cell is due to a violation of the complex relationship of metabolic reactions as a result of different levels of changes in their rates and damage to the molecular mechanism of active transfer of soluble substances through the cell membrane. Along with this, there is a change in the qualitative composition of microorganisms. Some groups of them multiply and when low temperatures, causing infection of injured during harvesting and transportation of fruits and vegetables. The infection then spreads to healthy, undamaged fruits and vegetables.

With respect to temperature, all microorganisms are divided into three groups: THERMOPHILES (55-75 о С); MESOPHILES (25-37 about C); PSYCHROPHILES (0-15 o C).

For refrigeration technology, psychrophilic microorganisms in food products are of great importance. They are contained in soil, water, air, having the ability to seed processing equipment, tools, containers, food directly. They multiply actively on foods with low acidity - meat, fish, milk and vegetables.

Freezing food is accompanied by a decrease in the number of microorganisms and their activity. In the initial period of freezing, when the bulk of the water turns into ice, there is a sharp decrease in the number of cells of microorganisms (zone A). This is followed by a slowdown in the reproduction of microorganisms (zone B). Then the process is stabilized, and a certain amount of resistant cells of microorganisms remains (zone C).

The death of microorganisms during freezing with the greatest intensity occurs at temperatures from -5 to -10 o C. A number of yeasts and molds are capable of vital processes up to temperatures of -10 to -12 o C.

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"T. V. Solyanik, MA Glaskovich MICROBIOLOGY MICROBIOLOGY OF ANIMAL AND PLANT FEEDS Recommended ... "

-- [ Page 1 ] --

MINISTRY OF AGRICULTURE

AND FOOD OF THE REPUBLIC OF BELARUS

MAIN DEPARTMENT OF EDUCATION, SCIENCE AND PERSONNEL

Educational institution

"BELARUSIAN STATE

AGRICULTURAL ACADEMY"

T. V. Solyanik, M. A. Glaskovich

MICROBIOLOGY

FEED MICROBIOLOGY

ANIMAL AND VEGETABLE

ORIGIN

Recommended by the educational and methodological association for education in the field Agriculture as a course of lectures for students of higher education institutions studying in the specialty 1-74 03 01 Zootechnics Gorki BGSKhA UDC 636.085: 579.67 (075.8) ББК 36-1Я73 С60 Approved by the methodical commission of the Faculty of Zoo on 03/25/2014 (protocol No. 7) and Scientific and methodological by the Council of the Belarusian State Agricultural Academy 12/03/2014 (minutes No. 3)

Candidate of Agricultural Sciences, Associate Professor T. V. Solyanik;

Candidate of Agricultural Sciences, Associate Professor M.A.Glaskovich

Reviewers:

PhD in Veterinary Science, Associate Professor of the Department of Microbiology and Virology, EE "VGAVM" P. P. Krasochko;

Candidate of Agricultural Sciences, Associate Professor of the Department of Pig Breeding and Small-scale Livestock Breeding, EE "BGSKhA" N. M. Bylitskiy Solyanik, T. V.

C60 Microbiology. Microbiology of animal and vegetable feed: a course of lectures / T. V. Solyanik, M. A. Glaskovich. - Gorki: BGSKhA, 2014 .-- 76 p. : ill.

ISBN 978-985-467-536-7.

In accordance with the program of the discipline, the course of lectures is compiled for students of higher educational institutions. In the lectures, the chemical composition of feed, the characteristics of microorganisms, the scale of losses in canned feed caused by the activity of microorganisms are considered in detail. The microbiological analysis of feed, microflora of silage and green mass, aerobic decomposition of feed, methods for studying pathogens of secondary fermentation are presented in an accessible form.

For students of institutions of higher education studying in the specialty 1-74 03 01 Zootechnics.

UDC 636.085: 579.67 (075.8) BBK 36-1Я73 ISBN 978-985-467-536-7 © UO "Belarusian State Agricultural Academy", 2014

INTRODUCTION

Forage in livestock or poultry farming accounts for about 70% of the cost of finished products, so every owner interested in highly profitable farming takes care of them first of all. It is not new to anyone that the feed not only needs to be grown and collected from the field in time, but also properly prepared.

Hay (straw) is stored in hay bales, bales or silos. For some succulent feeds (root crops), warm storage facilities are needed or piles (piles) are well insulated. Concentrated feed requires formulations or elevators. The most difficult problem is the preparation and storage of succulent feed - silage and haylage.

It should be borne in mind that these two types of food make up over 50% of the nutritional value of the winter ration of ruminants. And in intensive animal husbandry, when switching to the current feeding of animals with the same type of diet, these feeds become the main component of the diet all year round. Therefore, the quality of silage and haylage is the quality and efficiency of animal feeding in general.

The canning of feed is currently accompanied by large losses. If silage is done properly, for example in horizontal silos, losses average around 20%. With unskilled work, they increase significantly. Based on numerous studies, it can be stated that the amount of losses caused by the activity of feed microorganisms is often underestimated. When compiling the feed balance, only “inevitable” losses as a result of “waste” are foreseen. However, it should be borne in mind that the silage under the layer spoiled as a result of secondary fermentation (top and side layers) is characterized by a high pH and is not suitable for feeding to animals. Silage, which has undergone self-heating as a result of aerobic processes, loses its fodder value by half. Moldy hay, grain, sour silage are the cause of many diseases of farm animals.

Even under favorable conditions for natural fermentation, a lot of nutrients are lost when canning green plants. Eliminating these losses is equivalent to increasing the yield of forage crops by 20–25%. In addition, the usual traditional method of ensiling is not suitable for grasses with a high protein content (over 17% in dry matter).

According to modern concepts, the success of canning is determined by the total effect of the main preserving factors: active acidity, the toxic effect of the lactic acid molecule and specific antibiotic substances of lactic acid bacteria. Lactic acid bacteria are also useful in that they are producers, in addition to lactic acid and antibiotics, of other biologically active substances (vitamins, amino acids, etc.). All this leads to the search for new environmentally friendly biological products based on lactic acid bacteria that regulate and direct the microbiological process along the path of the desired homofermentative lactic acid fermentation.

Productively valuable strains of lactic acid bacteria should have the ability to actively multiply, be characterized by a high energy of acid formation, that is, to form a large amount of lactic acid, sufficient for a rapid stable increase in the acidity of canned feed.

Knowledge of the physiological and biochemical characteristics of individual groups of microorganisms found in canned feed, and the factors that limit or stimulate their development, is necessary in order to eliminate errors in the preparation, storage and feeding of canned feed.

1. ABOUT THE SPECIFIC FEATURES OF THE CHEMICAL

COMPOSITION AND NUTRITION OF FEEDS

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Hay - dried stems and leaves herbaceous plants cut green until they reach their full natural maturity. It is used as a food product for farm animals in areas where climatic conditions do not allow year-round use of fresh feed. Mowing hay is called haymaking.

Hay is one of the main feeds for cattle, sheep, horses during the stall period. High-quality hay serves as a source of protein, fiber, sugars, minerals, vitamins D and B.

The nutritional value of hay largely depends on its quality. The main condition for obtaining high-quality hay is timely mowing of grasses. The methods and duration of drying herbs have a significant impact on the quality of the hay. By the method of field drying, loose and pressed hay is harvested. The use of flattening of herbs and drying of wilted herbs by the method of active ventilation can reduce the duration of drying herbs. Active ventilation (when harvesting loose chopped and non-chopped, as well as pressed hay) makes it possible to increase the total collection of nutrients by 10-15%, increase the nutritional value of hay by 20% and reduce carotene losses by 2 times.

Conservation of wet hay with liquid ammonia is used, which makes it possible to increase the nutritional value of hay by 10–25%.

The general assessment of hay and its classification is made in accordance with GOST 4808–87. The following indicators are taken as the basis for the general assessment of hay: the phase of vegetation of grasses at the time of harvesting, color, smell, content of dry matter in hay, harmful and poisonous plants, mineral impurity. The quality assessment of hay is determined on the basis of organoleptic characteristics and laboratory tests.

Organoleptic indicators establish the general condition of the hay: appearance, smell, signs of spoilage, which characterize the quality of its cleaning and storage. The quality of the hay must meet the requirements of GOST 4808–87. According to GOST, a general assessment of hay and its classification are made.

Depending on the botanical composition, hay is divided into the following types:

1) seeded legumes (legumes more than 60%);

2) seeded cereal (cereals more than 60% and legumes not less than 20%);

3) seeded legume-cereal (legumes from 20 to 60%);

4) natural forage lands (cereals, legumes, etc.).

For hay, sown grasses and grasses of natural forage lands should be mowed:

1) legumes - in the budding phase, but not later than the full flowering phase;

2) cereals - in the heading phase, but not later than the beginning of flowering phase.

The color of the hay should be:

1) seeded legume (legume-cereal) - from green and greenish-yellow to light brown;

2) seeded cereal and hay of natural forage hayfields - from green to yellow-green.

Hay made from sown grasses and grasses of natural forage lands should not have a musty, moldy and putrid smell.

In hay from sown grasses and grasses of natural forage lands, the mass fraction of dry matter must be at least 83% (moisture - no more than 17%).

Hay from sown grasses and grasses of natural lands is subdivided into three classes depending on the content of crude protein and metabolic energy or OCE (Table 1).

In hay made from sown herbs, the content of harmful and poisonous plants is not allowed. The content of harmful and poisonous plants in the hay of natural forage lands is not allowed (for the 1st class - no more than 0.5%, for the 2nd and 3rd classes - no more than 1%).

Table 1. Requirements for hay (GOST 4808-87)

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Improving the quality of feed is one of the most real and tangible reserves in creating a solid feed base for the country's animal husbandry. The problem of improving the quality of feed is complex and provides for the receipt of raw materials with a high content of nutrients and environmentally friendly.

Full satisfaction of the need for feed can be achieved not only by increasing the yield of forage crops, but also by improving the quality, reducing the loss of nutrients in feed during harvesting, processing and storage. The success of the business largely depends on the choice of the most effective way of preserving green plants.

V last years a widespread canning method, such as silage, which allows you to preserve feed with minimal loss of nutrients, especially the carbohydrate part. Properly prepared haylage is fodder from plants harvested in the early phases of the growing season (mainly legumes), dried to a moisture content of 45–55% and stored under anaerobic conditions (without air access). Subject to the basic technological requirements when laying and storing silage, as a rule, feed is obtained High Quality with its characteristic chemical composition and nutritional value.

The haylage preparation technology consists of the following sequentially performed operations: mowing and flattening of grasses (legumes); withering and raking into rolls; selection; shredding and loading into vehicles; transportation and unloading in storage;

thorough ramming (in trenches) and safe cover.

Hayage, depending on the botanical composition and moisture content of crushed up to 3 cm plants, is divided into the following types:

1) haylage from legumes and cereal-leguminous grasses, withered to a moisture content of 45–55%;

2) haylage from cereal and cereal-leguminous herbs, withered to a moisture content of 40–55%.

Haylage is subdivided into three classes in accordance with the requirements of GOST 23637–90 (Table 2).

Plants for making silage should be cut during the following stages of development:

Perennial legumes - in the budding phase, but not later than the beginning of flowering;

Perennial grasses - at the end of the tube emergence phase before the beginning of earing;

Perennial grass mixtures are mowed in the above-mentioned phases of the predominant component.

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Note. The norms are established taking into account that the grades of haylage are determined not earlier than 30 days after the hermetic shelter of the mass laid in the trench or tower, and not later than 15 days before the start of feeding the finished haylage to animals ...

Annual leguminous plants, legume-cereals and their mixtures are mowed not earlier than the formation of beans in two or three lower tiers. The silage should have a characteristic odor, without mucus consistency.

Mold is not allowed. Mass fraction of ash insoluble in hydrochloric acid should not exceed 3%.

1.3. Chemical composition and nutritional value of silage and silage Silage is fodder made from freshly cut or dried mass preserved under anaerobic conditions by organic acids or preservatives formed during this process.

Silage is the fermentation of the succulent mass of plants with organic acids, mainly lactic acid. The moisture content of the silo should be 65–75%. To prevent rotting of the feed, air is removed from the laid mass by carefully compaction.

Not all plants are equally good at silage.

Easy silos include: corn harvested at the stage of milky-wax ripeness; sorghum - during the period of waxy ripeness of the grain;

sunflower, harvested during the flowering of baskets from the third part of the plant; cereal grasses mown at the beginning of earing; legume-cereal mixtures, table and fodder cabbage, rapeseed, beets, pumpkin, carrots, fodder watermelons, aftertas of meadow grasses; reeds and reeds, harvested before flowering; beet and carrot tops.

Difficult to feed plants: clover, alfalfa, sweet clover, sainfoin, vetch, sedge, reeds and reeds, harvested during the flowering period. It is better to lay these plants in a mixture with light-shedding plants in a 1: 1 ratio.

Silage is a type of silage made from herbs, withered to a moisture content of 60.1–70.0%. Silage also includes fodder prepared by the method of uniform mixing and crushing of chopped freshly cut leguminous grasses with cereals, dried to a moisture content of 40–45%, in a ratio of 1: 1–1.3: 1.0. In terms of dry matter content (30.0–39.9%), silage occupies an intermediate position between silage from freshly cut plants and haylage.

Silage, depending on the botanical composition of plants and cooking technology, is subdivided into the following types: corn silage, annual and perennial silage and silage.

Silage can be prepared with the use of enriching nitrogen-containing substances or without them, with the use of preservatives and moisture-absorbing additives (straw, chaff, etc.) or without them, with or without withering the green mass.

Forage crops intended for silage preparation should be harvested during the following growing phases:

Corn - in the phase of waxy and milky-wax ripeness of grain;

it is allowed to harvest corn in earlier phases in repeated crops and in areas where this crop, due to climatic conditions, cannot reach these phases;

Sunflower - in the beginning of flowering phase;

Lupine - in the lustrous bean phase;

Perennial legumes - in the budding phase - the beginning of flowering;

Cereal grasses - at the end of the tube emergence phase - the beginning of earing (panicle sweeping);

Herbal mixtures of perennial legumes and cereal grasses - in the above-mentioned phases of the growing season of the predominant component;

Annual legume-cereal grass mixtures - in the phase of wax ripeness of seeds in two or three lower tiers of leguminous plants;

Annual cereal and cereal-legume mixtures are in the phase of milky grain ripeness.

The silage should have a pleasant fruity aroma of pickled vegetables, the color characteristic of the raw materials, and no slack consistency. Mold is not allowed.

The maximum content in the silo is allowed: nitrates - 500 mg / kg, nitrites - 10 mg / kg.

Maximum permissible levels of heavy metals, mg / kg: mercury - 0.06; cadmium - 0.3; lead - 5.0; copper - 30.0; zinc - 50.0; iron - 100.0; nickel - 3.0; fluorine - 20.0; cobalt - 1.0; molybdenum - 2.0; iodine - 2.0.

The residual amount of pesticides must not exceed the permissible levels.

Forage silage is divided into four classes: higher, first, second and third. Corn silage must meet the requirements given in table. 3.

Silage from annual and perennial freshly cut and withered plants must meet the requirements specified in table. 4 and 5.

Evaluation of the quality of silage from forage plants is carried out no earlier than 30 days after the hermetic shelter of the mass laid in the storage, and no later than 15 days before the start of feeding to the animals.

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* The zones include the following regions: the first - Brest and Gomel; in the second (central) - Grodno, Minsk and Mogilev;

in the third (northern) - Vitebsk.

Table 4. Characteristics of quality classes of silage from annual and perennial freshly cut and dried plants

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Notes: 1. In silage preserved with sodium pyrosulfite, pH is not determined.

2. In silage preserved with sodium pyrosulfite, propionic acid and its mixtures with other acids, the mass fraction of butyric acid is not determined.

3. Silage with straw of the highest class is not evaluated.

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2. BRIEF DESCRIPTION

FODDER MICROORGANISMS

2.1. Epiphytic microflora, its composition and features Epiphytic microflora are microorganisms found on the surface of growing plants. Its quantitative and qualitative (species) composition varies greatly and depends on the season, locality, type and stage of plant development, the degree of their pollution and many other conditions. Thus, the following number of microorganisms accounted for 1 g of fresh mass: fresh grassland - 16,000, alfalfa - 1,600,000, corn - 17,260,000.

The diverse microflora contains only a relatively small amount of lactic acid bacteria (Table 6).

Table 6. Quantitative and qualitative composition of microorganisms, cells / g

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There were about 1.6 million microorganisms in 1 g of alfalfa, but among them there were only 10 lactic acid bacteria. Therefore, there were 160,000 undesirable microorganisms for 1 desired microorganism. The exception is corn. There were more than 100,000 lactic acid bacteria per 1 g of fresh weight of this plant. Apparently, the good silage capacity of maize is due to both a favorable ratio of nutrients and a large number of lactic acid bacteria. These factors also determine the good silage capacity of other feeds with a high sugar content (beet tops, millet, etc.).

Thus, the plants contain a huge number of various microorganisms, but this amount is insignificant in comparison with the density of microorganisms after setting and during storage in one or another storage facility.

2.2. Microflora of hay and wet grain

The most important task of feed production is to preserve the good quality of feed. There are a number of reasons for the loss of nutrients, a decrease in the taste and technological properties of feed.

Drying is the most common way of preserving green mass and other forage. Drying of hay is carried out in different ways - in swaths, swaths, heaps, on hangers, etc. Even in dry weather and fast drying, some losses of nutrients in the feed are inevitable, since respiration and other enzymatic processes continue in the plant mass. In the case of more or less prolonged drying, the role of the processes noted increases greatly, and this, in turn, leads to an increase in losses, which are largely associated with microorganisms multiplying on moist plant matter. To limit the loss of nutrients, they tend to use artificial drying of hay, using forced ventilation with atmospheric or heated air.

The phenomenon of thermogenesis becomes tangible only under conditions of hindered heat transfer. Otherwise, heat is dissipated from the environment in which microorganisms multiply, without noticeable heating of the substrate. Therefore, in practice, only significant accumulations of various materials are warmed up, that is, such masses in which heat accumulation can occur.

With self-heating of the plant mass, a pronounced change in microflora is observed. First, mesophilic microorganisms multiply in the warming mass. With an increase in temperature, they are replaced by thermophiles, which contribute to an increase in the temperature of organic substances, since they have an exceptional rate of reproduction.

Strong heating of a sufficiently dry and porous mass can cause carbonization and the formation of flammable gases such as methane and hydrogen, which are adsorbed on the porous surface of charred plant particles, as a result of which spontaneous combustion can occur. It is highly probable that iron compounds play the role of catalyst during ignition. Ignition occurs only in the presence of air and only if the mass is not sufficiently compacted. In windy weather, spontaneous combustion is more frequent.

Thermogenesis causes significant harm. It causes spoilage of the hay. However, with moderate self-heating, thermogenesis may be desirable. For example, "self-matured" straw as a result of heating is better eaten by livestock, etc. The phenomenon of thermogenesis is used to prepare the so-called brown hay. It is prepared in areas where hay drying is difficult due to climatic conditions. At the same time, not solar energy is used to dry the feed, but the heat released as a result of the vital activity of microorganisms living in the plant mass.

In dried feed, microorganisms are in anabiotic state. When the feed is moistened, they begin to multiply and cause spoilage.

Theoretically, the preparation of hay is associated with the drying of a culture with an initial water content of 65–75% to a water content of 10–16%, at which all biochemical and microbiological activity ceases. In practice, hay is not dried to such a low water content and in fact it is considered safe to store hay after its average water content has dropped to 20%. This is a high enough humidity at which mold growth occurs, unless further water loss occurs during storage.

In all cases, in the first 2–3 days of storage, the first temperature peak is observed, followed by a second, higher peak.

It is the second peak that is due to the respiration of rapidly developing fungi. The higher the water content of 20%, the more the risk of mold growth and increased dry matter loss increases. So, if loose bales of hay are stored with a water content of 35–40%, the loss of dry matter will be about 15–20%, and soluble carbohydrates will be complete. Microbiological analysis will reveal a large number of microorganisms, including dangerous thermophilic actinomycetes.

Science and practice have established that the nutritional value of grain from harvesting to drying, only as a result of enzymatic processes occurring, can decrease by 20% or more. More significant losses of nutritional value of grain are when they are harvested in rainy weather.

Raw and damp grain begins to self-heat on the 2-3rd day, and then germinate, mold and deteriorate. So, at a daytime temperature of 25 ° С, and at night 16 ° С, fresh grain can contain 800 moldy fungi, after 2 days (in a silo tower) - 15,000, in grain adhered to the walls of the tower - 7,500,000.

Conditioned or, as it is sometimes called, critical moisture content of grain, laid for long-term storage, is considered to be 10-15% moisture. At higher humidity, the grain deteriorates quickly. One of the main reasons for self-heating of grain is the development of molds and bacteria. If the germination of the grain begins when 40% moisture is absorbed by its mass, then the development of bacteria occurs at 16%, and the reproduction of molds - at 15% moisture.

The difficulty of storing feed and grain raw materials is that it is not possible to get them clean from microorganisms and bacteria. Microorganisms and bacteria are widespread in nature and are always present in feed and raw materials. Unfavorable storage conditions of feed contribute to the development and growth of microorganisms, while significantly impairing the nutritional properties, and sometimes making them completely unsuitable for nutrition. One of the main reasons for the poor quality of feed and raw materials is their defeat by molds, many of which produce by-products of their vital activity - mycotoxins.

The term "wet grain" is generally applied to grain with a moisture content of 18 to 20%. Wet grain begins to warm up within a few hours after harvesting, mainly due to microorganisms. If storage conditions are inappropriate and uncontrolled, the temperature of the grain will rise to a level at which very dangerous actinomycetes can grow successfully, which cause a variety of different diseases in animals and humans. If the grain contains more than 18% water, secondary changes occur, which are caused by yeasts belonging to the genera Candida and Hansenula. These microorganisms are able to grow at very low oxygen levels, and under these conditions weak alcoholic fermentation can occur. This kind of fermentation leads to a decrease in the sucrose content and an increase in the content of reducing sugars in the grain, the formation of various flavors, and damage to the gluten.

2.3. Microbiological processes occurring during the maturation of haylage It is generally accepted that the main community of microorganisms that are detected during the maturation of haylage is represented, as in silage, by three main physiological groups (lactic acid, putrefactive bacteria and yeast), but in smaller quantities. The maximum number of microorganisms in the dried material is detected up to 15 days (in the silo - up to 7). The haylage contains fewer organic acids, more sugar, and its acidity is usually lower than that of silage.

The biological basis for making haylage is to limit the residual respiration of plant cells and unwanted microorganisms by means of "physiological dryness". The water-holding force in the haylage is approximately 50 atm., And the osmotic pressure in most bacteria is 50–52 atm., That is, with a grass moisture content of 40–55%, water is in a form that is inaccessible to most bacteria. Due to the increased osmotic pressure in the silage mass, butyric acid bacteria and their spores cannot use the feed moisture for their development and germination. Molds can develop at the specified humidity, but their existence is difficult due to the lack of air (oxygen).

Osmotolerant species of lactic acid bacteria can develop at this humidity. In cultures of lactic acid bacteria in haylage, osmotic activity, reproductive activity, accumulation of lactic acid, as well as the ability to ferment complex carbohydrates (starch, etc.) are higher than in cultures of lactic acid bacteria in silage.

Therefore, as in the case of ensiling, optimal conditions should be created for the development of lactic acid bacteria (continuous compaction during setting and hermetic covering with plastic wrap to restrict air access). If the storage is not sufficiently compacted and leaky, this leads to warming up, moldy feed and other undesirable aerobic processes.

It is impossible to make good quality silage in such conditions.

As a result of self-warming processes, the digestibility of nutrients, especially protein, is sharply reduced. The technology of harvesting haylage and silage from grasses with low moisture content is described in detail in many books and manuals, we will only emphasize here that, subject to the basic technological methods, the nutritional value of haylage is higher than the nutritional value of silage prepared from natural or low moisture feed. 1 kg of natural feed contains 0.30–0.35 feed. units

2.4. Microbiological processes during ensiling

The quantitative and qualitative (species) composition of the community of microorganisms that participate in the ripening of silage also depends on the botanical composition of the green mass, the content of soluble carbohydrates and protein in it, and the moisture content of the original mass.

So, for example, raw materials rich in proteins (clover, alfalfa, sweet clover, sainfoin, etc.), in contrast to raw materials rich in carbohydrates (corn, millet, etc.), are ensiled with prolonged participation in the processes of putrefactive bacteria and with a slow increase in the number lactic acid bacteria.

However, in any case, after planting the plant mass in the storage, a massive reproduction of microorganisms is observed. Their total number after 2–9 days can significantly exceed the number of microorganisms that enter with the plant mass (Table 7).

- & nbsp– & nbsp–

With all methods of ensiling, a community of microorganisms is involved in the maturation of silages, consisting of two diametrically opposite groups in terms of the nature of the effect on plant material: harmful (undesirable) and useful (desirable) groups. The nature of their relationship varies not only from symbiotic to antagonistic, which ultimately determine success or failure in the outcome of ensiling, but also from the nature of the silage material, air and temperature regimes.

Thus, in the process of ensiling, putrefactive microorganisms are replaced by lactic acid, which, due to the formation of lactic and partially acetic acids, reduce the pH of the feed to 4.0–4.2 and thereby create unfavorable conditions for the development of putrefactive microorganisms (see Table 7).

The conditions for existence (demand for oxygen, relation to temperature, active acidity, etc.) are not the same for different groups of microorganisms.

From the point of view of oxygen demand, there are conventionally three groups of microorganisms:

Breeding only in the complete absence of oxygen (obligate anaerobes);

Breeding only in the presence of oxygen (obligate aerobes);

Breeding both with and without oxygen (facultative anaerobes).

Most microorganisms that cause perverse fermentation do not tolerate pH below 4.0, so it is desirable to reach this optimum acidity level quickly.

To limit the activity of harmful microorganisms and stimulate the reproduction of beneficial bacteria, you should know the characteristics of individual groups of microorganisms.

Table 8 schematically shows the physiological and biochemical characteristics of the main representatives of microorganisms involved in ensiling processes.

Table 8. Conditions for the existence of microorganisms in the silo

- & nbsp– & nbsp–

To obtain high-quality silage, the creation of anaerobic conditions is equally important - a dense rammer and good sealing.

In silage obtained under non-hermetic conditions (aerobic), the number of lactic acid bacteria after an initial increase decreases rapidly, in hermetically-sealed (anaerobic) conditions, it remains high. On the 7th day of fermentation under anaerobic conditions, a high percentage of homofermentative bacteria is observed, in aerobic conditions - pediococci.

Although later in this silo a sufficient number of lactic acid sticks appear, they can no longer prevent the growth of unwanted microorganisms.

Thus, lactic acid bacteria are distinguished by the following features that are important for ensiling:

1) need for metabolism, mainly carbohydrates (sugar, less often starch);

2) protein does not decompose (some species in negligible amounts);

3) they are facultative anaerobes, that is, they develop without oxygen and in the presence of oxygen;

4) the temperature optimum is most often 30 ° C (mesophilic lactic acid bacteria), but in some forms it reaches 60 ° C (thermophilic lactic acid bacteria);

5) maintain acidity up to pH 3.0;

6) can thrive in silos with a very high dry matter content;

7) easily tolerate high concentrations of NaCl and are resistant to some other chemicals;

8) in addition to lactic acid, which plays a decisive role in suppressing unwanted types of fermentation, lactic acid bacteria secrete biologically active substances (B vitamins, etc.). They have prophylactic (or medicinal) properties, stimulate the growth and development of farm animals.

Under favorable conditions (sufficient content of water-soluble carbohydrates in the initial plant material, anarobiosis), lactic acid fermentation ends in just a few days and the pH reaches its optimum value of 4.0–4.2.

2.4.1. Corn silage

The methods of harvesting and storing corn silage currently used in production conditions do not provide high-energy feed. Often, even early-maturing hybrids do not have time to reach the optimal stages of development (milk-wax, wax ripeness of grain) due to climatic conditions, especially in the northern part of Belarus. The high moisture content of the original green mass and a relatively high sugar content lead, as practice shows, to obtain an over-acidified feed (pH 3.3–3.7) with a low nutritional value (0.12–0.14 feed units in 1 kg of feed) ...

In addition, there is a concern about the deterioration in the aerobic stability of good quality corn silage (grain).

In some cases, significant losses are observed in the process of removing corn silage from storage and feeding it, despite strict adherence to the basic technological methods during filling (moisture reduction, timely filling, reliable compaction and shelter). This occurs as a result of the activity of the aerobic microflora, which uses mainly water-soluble carbohydrates and lactic acid as an energy source. In practice, this is accompanied by a thermal process, ultimately "aerobic propagation" of silage, which animals refuse.

2.4.2. Microflora of green mass of corn

Studies of the microflora of fresh green mass of corn and cobs during the preparation of silage showed that its representatives participating in the maturation of silage fodder are detected in approximately the same numerical ratio as in other types of fresh raw materials for silage. When analyzing the quantitative and qualitative composition of the corn microflora, the predominant amount of putrefactive bacteria was established - Bacillus megaterium, Bacterium levans, Pseudomonas herbicola levans (Table 9).

A large number of yeasts are detected - Hansenula anomala, Candida krusei, Pichia membranae faciens, Saecharomyces exiguus, as well as molds Aspergillus fumigatus, Fusarium sporotrichiella, Geotrichum candidum, etc.

The main representatives of lactic acid bacteria in maize are rod-shaped forms of the Lactobacillus plantarum type.

Table 9. The number of microorganisms in the fresh green mass of corn during loading into the storage, mln.

cells / g silage

- & nbsp– & nbsp–

The microflora of freshly harvested ears is much poorer than the microflora of green mass collected at the same time and in the same field. This indicates that the wrapper is a protective cover of the cob against microflora. So, 1 g of the wrapper contains units and tens of millions of putrefactive bacteria, in the cob itself putrefactive bacteria were found in the amount of tens of thousands, and lactic acid - hundreds and thousands of cells.

2.4.3. Silage corn microflora

Corn is rich in carbohydrates, therefore, when creating anaerobic conditions during ensiling, lactic acid bacteria rather quickly acquire a numerical superiority over putrefactive ones. If on the 2nd day in corn silage lactic acid bacteria were numbered 430 million, putrefactive - 425 million in 1 g of silage, then after 15 days, when the number of lactic acid bacteria increased to 900 million, putrefactive bacteria were isolated in very small quantities. Butyric acid bacteria do not develop under optimal conditions of ensiling.

Observation of the dynamics of the maturation processes of corn silage showed that not only putrefactive and lactic acid bacteria, but also yeast, participate in the first phase. Their number increases significantly on the 2nd day.

Yeast activity in silage is considered undesirable for two reasons.

First, they compete with lactic acid bacteria for sugars, which ferment mainly to ethyl alcohol, which does not represent a significant preservative value. During the formation of ethyl alcohol from glucose, pyruvate is first formed, which is then decarboxylated to acetaldehyde, which is reduced to ethyl alcohol. In addition to ethyl alcohol, yeast under anaerobic conditions also form other products (acetic, propionic, butyric, isobutyric acids, n-propanol, isobutanol, isopentanol). In addition to hexose sugars, some yeasts use pentoses (D-xylose, D-ribose), polysaccharides (starch), alcohols (mannitol, sorbitol).

Secondly, yeast is the main causative agent of aerobic decomposition of silage, using organic acids (lactic, acetic, citric).

Thus, in corn rich in carbohydrates, with an optimal ensiling regime, in the initial period of ripening, the fermentation process is due to the predominant participation of the community of microorganisms fermenting carbohydrates: putrefactive, lactic acid and yeast. Putrefactive bacteria dominate for no more than the first 2–5 days, and then, under the influence of an increasing number of lactic acid bacteria, they stop their development in conditions of low pH.

Lactic acid bacteria, having reached a dominant position, almost completely replace putrefactive bacteria. Then, as the pH level further decreases, their number decreases.

The aerobic conditions in the silo are unfavorable for mold growth. They, as a rule, develop only in certain areas, at the edges and on the surface, which are in contact with air.

In case of violation of the technological regime of ensiling in the corn mass, the activity of yeast and butyric acid bacteria, i.e., microorganisms that destroy carbohydrates, is most affected. Such silage is characterized by a high content of acetic and even butyric acid. The presence of a large amount of acetic acid always indicates poor silage quality.

2.4.4. Microflora of frost-bitten corn In the northern regions of the Republic of Belarus, there are cases when frost-bitten corn is ensiled. With the correct technology of silage of frozen corn, in 3–5 days lactic acid bacteria acquire a dominant position, their number is almost 10 times higher than the number of putrefactive bacteria, and yeast on this material is detected even in greater quantities than in matured silos made from frozen corn.

On this material, the main ecological community of microorganisms is represented by lactic acid and putrefactive bacteria, as well as yeast. From putrefactive bacteria, the same species that are usually found during ensiling of green mass of various plants, including corn, were isolated - Pseudomonas herbicola and Bacterium levans.

Biochemical data indicate that the maturation process of these silos is characterized by a rapid and very high accumulation of organic acids. At the same time, it was noted that, with storage, the acidity in these silos significantly decreases. This can be explained by the consumption of acids by the yeast, since the latter are found here even in 9-month-old silage, which leads to lower quality finished feed.

After 5 months of storage, the quality of the silage taken in the middle of the storage facility and in deeper layers, in terms of the composition of organic acids, microflora and organoleptic characteristics, was good, while in the upper part of the structure poor quality silage was obtained. The silage from the upper layer of the storage had a pungent smell of butyric acid, and putrefactive bacteria were detected in it in a dominant amount over lactic acid: 30 and 23 million bacteria per gram of silage, respectively. Here, butyric acid bacteria were found in a significantly greater amount in comparison with the silage lying in the middle of the structure.

Thus, the microbiological processes of maturation of silage from frost-damaged maize proceed more intensively than during ensiling of un-damaged maize; with a greater participation of unwanted microflora in the upper layers. A delay in harvesting frozen corn is unacceptable, as this contributes to rapid development on frozen plants of unwanted microflora and significantly reduces the quality of the finished silage.

Therefore, frost-damaged corn must be quickly removed and immediately silted in compliance with all technological methods.

2.4.5. Influence of corn silage on metabolism in the body of animals 0.7–0.9 kg of organic acids are introduced into the body of an animal with silage per day, which have a significant effect on the processes of digestion and metabolism. But if the silage is peroxidized, then the amount of acids increases significantly. Such silage has a negative effect not only on metabolic processes, but also on the taste and technological qualities of milk, as well as on the products of its processing (cheese, butter).

Long-term feeding of spontaneously fermented corn silage in pure form (without other feed) inhibits fermentation processes in the rumen of ruminants, inhibits the development of microflora and causes a decrease in the digestibility of nutrients in the diet, as well as average daily gains in live weight. Animals refuse corn feed, which has undergone secondary fermentation processes.

A decrease in alkaline reserve and blood sugar was found in cows that ate abundantly silage of spontaneous fermentation.

Feeding 20–25 kg of corn silage containing butyric acid to lactating cows caused a severe form of acidosis and significantly increased the acidity of milk.

The silage type of feeding of cows with a lack of easily digestible carbohydrates in the diet reduces the amylolytic activity of the contents of the rumen and chyme of the cecum. Long-term feeding of 25-30 kg per day of spontaneously fermented peroxidized corn silage to cows negatively affects the reproductive capacity of cows, the biological value of colostrum and milk, which leads to a decrease in the growth of calves and their resistance to gastrointestinal diseases. The scientific findings have been validated in the practice of feeding cows with corn silage.

It should be noted that ketonemia in the body of high-yielding cows develops faster than low-yielding ones. Violation of the ratio of carbohydrate and fat metabolites in the body leads to the appearance in the blood and tissues of a significant amount of under-oxidized metabolic products in the form of ketone (acetone) bodies and the development of ketosis.

The phenomena of ketosis in the body are usually associated with a violation of carbohydrate-fat metabolism with a simultaneous decrease in the amount of sugar in the blood and a sharp increase in ketone bodies. The main reason for ketosis is the intake of acidic metabolic products into the body during periods of unusual conditions for the assimilation of nutrients from the diet, i.e. pregnancy, lactation, stress, etc. Hence the greatest predisposition to ketosis in female farm animals consuming an increased amount of silage.

Ketonemia, regardless of the cause that caused it, is characterized by the accumulation of ketone bodies in the blood and tissues under the influence of activated acetic and acetoacetic acids. Acetoacetic acid is converted to hydroxybutyric acid by the enzyme dehydrogenase, and this reaction is reversible. In the rumen of ruminants, acetoacetate decarboxylase was found, which allows the rumen tissues to use acetoacetic acid with the release of acetone and carbon dioxide. These metabolites are eliminated from the body in urine and exhaled air.

If, for example, a characteristic smell of acetone is felt with the air exhaled by ruminants, then this is an indicator of ketosis.

The precursors of ketone bodies include tyrosine, leucine, isoleucine, and phenylalanine, synthesized in the rumen and supplied with food. Up to 300 g of ketone bodies can be formed in a cow's body per day. The main source of keto formation in the body is butyric acid. Removing it from the body stops ketonemia. The place of formation of ketone bodies is considered to be the tissues of the rumen, liver, and sometimes the mammary gland. Ketone bodies are utilized by almost all body tissues.

The main condition for the final breakdown of ketone bodies to carbon dioxide and water in the body is the presence of a sufficient amount of glucose in tissues and blood. The maximum utilization of ketone bodies by body tissues is possible when their concentration in the blood is at the level of 20 mg%, exceeding this limit leads to ketonemia. The elimination of ketone bodies from the body with urine, milk and exhaled air is accompanied by the release of an equal amount of sodium and potassium ions, which is the reason for a decrease in the alkaline reserve of blood.

For the prevention of ketonemia in ruminants, hormonal drugs such as insulin, ACTH, thyroxine, as well as glycerol, glucose, propionic acid and its salts are usually recommended. Their introduction into the body is considered necessary to increase propionic acid in the rumen and decrease butyric acid. This is also facilitated by the balancing of diets in protein and carbohydrates, feeding the animals with starchy and sugary fodders.

Feeding cows silage with propionic acid sourdough activates the activity of cellulolytic bacteria in the digestive tract, as a result of which the decomposition of cellulose increases, the development of propionic acid bacteria in the rumen is stimulated, and the nutrients of the diet are better absorbed. Thus, the coefficient of digestibility of the main components of the diet with such a silage is higher than that of the diet with silage of spontaneous fermentation: for crude protein - by 4%, raw fat - by 8.4%, crude fiber - by 2.1% and nitrogen-free extractives - by 3%. Silage with sourdough in lactating cows causes an increase in sugar concentration by 10–15%, reserve alkalinity - by 20–40 mg%, reduces the concentration of ketone bodies by 5–7 mg% and thereby prevents acidosis. In pregnant dry cows, digestion is activated, and the physiological state improves. This is evidenced by an increase in the blood alkaline reserve by an average of 10 mg%, sugar concentration by 20 mg%, a decrease in the level of ketone bodies in it by 4.6 mg% and the birth of healthy, viable calves. In lactating cows, the fat content of milk increases by 0.20–0.25%, the protein content - by 0.20–0.30% and lactose - by 0.10–0.20%.

The use of ammonium carbonates (UAS) in the amount of 10 kg / t of feed gives positive results in the deoxidation of corn silage. In addition, the silage is simultaneously enriched with protein.

2.4.6. Aerobic decomposition of corn silage

Silage of good and highest quality sometimes undergoes rapid rewarming when removed from storage or when air enters the storage.

In corn silage, aerobic loss, in some cases, reached 32% within 15 days.

In silos in which aerobic spoilage occurs, the zone of elevated temperature first spread on the surface of the silo in the storage (pile), and eventually deepened by 20–40 cm. Subsequently, the surface layer (0–15 cm) cooled, the pH in it increased to 8.5–10.0 and the development of molds began. Thus, in the first stage of spoilage, heating and an increase in pH take place, and in the second stage of spoilage, mold. The result of these negative phenomena is the destruction of lactic acid, carbohydrates and other valuable substances with the formation of mycotoxins hazardous to animal health.

2.4.7. Causes of aerobic degradation of feed

By "secondary" fermentation is meant the oxidation of organic acids (mainly lactic acid) formed during the ensiling process, with the access of air after the completed fermentation. This term, which has been used often in the past few years, is not entirely accurate in the scientific sense. If fermentation is a process of anaerobic breakdown of carbohydrates, then "secondary" fermentation is the opposite process of enzymatic decomposition when oxygen is available.

Air penetration leads to the rapid breakdown of carbohydrates, lactic acid and further to the breakdown of protein with an increase in the pH level. In practice, this is accompanied by a thermal process, an unpleasant odor, a violation of the structure of the feed (smeared, destroyed). Even with weak self-warming up to a temperature of 40 ° C, animals refuse such food.

Slow filling, delayed sealing are all procedures that contribute to an increase in the population of aerobic microorganisms, which will begin to actively develop as soon as the silo is opened.

2.4.8. Microflora of aerobic decomposition of feed

It has been established that the primary pathogens of secondary fermentation are yeast, which has the ability to assimilate (break down) lactic acid.

The presence of yeast in silage was first established in 1932, but its significance was underestimated until 1964, when it became clear that yeast plays a major role in the decomposition of silage when air is exposed to it. The lack of interest in these microorganisms was due to the fact that their number in the silage is insignificant. However, maize silage is often characterized by a high abundance of these microorganisms, especially when the aerobic phase in the silo has been prolonged.

The main yeast found in silage is divided into two groups:

1) "bottom" fermentation yeast, or sedimentary yeast, which preferentially ferments sugars (Torulopsis sp.);

2) yeast "top" fermentation, or membranous, with a weak ability to ferment, but effectively using lactic acid as a substrate (Candida sp., Hansnula sp.).

The study of the dynamics of fermentation showed that the yeast content in self-heating corn silage was initially 105–107 yeast per 1 g immediately after harvesting, and then gradually decreased. Most of the isolated yeast strains from such silos belong to Candida sp., Hansnula sp. The most common pathogens of instability, such as Candida krusei, Candida lamlica, Pichia strasburgensia, Hansenula anomala, are resistant to very low pH levels.

After 5 days of aerobic storage, unstable corn silage has an astronomically high number of not only yeasts, but also other microorganisms (Table 10).

- & nbsp– & nbsp–

Particularly striking is the presence in the silage of inhabitants of neutral or slightly alkaline soils - streptomycetes. Their presence, as well as "true" silage molds, is one of the reasons why such silage is unsuitable for feeding. But both in the presence of "true" mold fungi, and streptomycetes alien to silage, we are not talking about the primary pathogens of secondary fermentation, but about the secondary flora with aerobic instability.

At the end of spontaneous fermentation of corn silage, the amount of yeast is at least 104 cells per 1 g of feed (Table 11).

Table 11. Corn silage (final grade after 173 days)

- & nbsp– & nbsp–

Mold fungi, like yeast, play a negative role in the decomposition of silos when air is available, as they form toxic substances - mycotoxins. In the studied samples taken from silos before feeding, the following molds were isolated and identified: Aspergillus sp., Fusarium sp., Penicillium sp.

and others. In animals that received moldy corn silage containing A. fumigatus, inflammation of the small intestines, changes in the intermediate tissues of the lungs, loss of appetite, diarrhea were observed.

Violation of cardiac activity (pulse quickened, arrhythmic) and breathing, indigestion (atony of the rumen or increased intestinal motility), depression, refusal to feed are caused by mycotoxins Fusarium sporotrichiella, Geotrichum candidum. These mycotoxins give the silage a rancid odor and cause mycoses in farm animals.

2.4.9. Ways to Improve Aerobic Stability of Silage

Correct opening of the silo, microbiological analysis of the laid green mass in the silo, the use of chemical preservatives with fungicidal (fungistatic) properties are the main measures to limit microbiological spoilage during long-term feeding or aerobic storage of corn silage (wet grain).

The most obvious and effective way To prevent aerobic decomposition, it is necessary to feed the silage to the animals on the day it is removed from the silo. Frequent withdrawal of feed also increases decomposition on the exposed silo surface. Unloading should be carried out without moving the layers, disrupting the solidity of the silo remaining in the silo.

One of the possible measures to improve the aerobic stability of corn silage is the treatment of green mass with chemicals that inhibit aerobic microflora stern.

Table 12 shows the most commonly used preservatives that have a fungistatic (fungicidal) effect on the causative agents of secondary fermentation.

- & nbsp– & nbsp–

In practice, calcium formate and acetic acid do not have an inhibitory effect on yeast if the applied concentration is below 0.5%. Despite the rapid decomposition of sodium nitrite, hexamethylenetetramine, they are recommended for limiting secondary fermentation processes, since they "free" silage from yeast at the beginning of fermentation. The most effective fungistatic (fungicidal) preservatives on secondary fermentation processes are propionic and acetic acids, sodium benzoate, since they are largely preserved when the silage is removed from storage.

A comparative study of the fungistatic (fungicidal) properties of propionic, formic, benzoic acids, sodium benzoate, sodium nitrite, enrichment preservative (which contains propionic acid and urea), Finnish preservatives (like Viher) showed that sodium nitrite and benzoic acid, which inhibited the growth of yeast up to 98%. The strength of the effect of chemical preservatives depended on their dose, the concentration of hydrogen ions and the number of yeast cells.

The use of preparations created on the basis of combined homoenzymatic and heteroenzymatic strains of lactic acid bacteria also contributes to an increase in the safety of silage in the process of removing it from the silo and feeding it to animals. Although the inclusion of heteroenzymatic bacteria leads to some increase in nutrient loss during ensiling, it contributes to an increase in acetic acid in the feed and therefore to an increase in its aerobic stability.

Thus, the corn silage harvesting technology used in production conditions does not always provide a highly nutritious feed. Silage can be over-acidified, and its consumption by animals is low. Hence the low efficiency in the use of energy resources. Abundant feeding of animals with peroxidized silage leads to a violation of the level of sugar, alkaline reserve in the blood, to the development of ketosis, etc.

In practice, there are cases when good quality corn silage quickly "warms up" and very quickly grows moldy when it is removed from the storage or in the storage itself when air is available. The cause of aerobic instability is the presence of yeast (Candida sp., Hansenula sp.), Which can assimilate lactic acid.

The use of the latter leads to the fact that the acidic environment is replaced by an alkaline one (pH 8.5-10.0), favorable conditions are created for the development of mold, butyric acid, putrefactive microflora.

In the case when 1 g of the original silage mass contains more than 4 105 mushrooms, it is impossible to obtain aerobically stable silage from it and additional measures are necessary to limit losses.

To suppress the causative agents of secondary fermentation, there are preparations with fungicidal (fungistatic) activity. The best activity against yeast was shown by benzoic acid, sodium nitrite, which almost completely (98%) inhibited yeast.

To improve the aerobic stability of corn silage, complex biological products based on homo- and heteroenzymatic lactic acid bacteria are proposed.

2.5. Influence of the main environmental factors on the vital activity of lactic acid bacteria 2.5.1. Influence of the chemical composition of the original plant green mass on the enzymatic activity of lactic acid bacteria The intensity of the formation of lactic acid formed by lactic acid bacteria depends on the quantitative ratio of microorganisms and the chemical composition of the plant mass.

In most cases, the natural presence of lactic acid bacteria is insufficient to achieve a rapid increase in the acidity of the silage mass. An exception is corn and other feedstocks rich in free sugars. The peculiarity of fermentation during ensiling of such green mass is that already on the 2-3rd day there is a numerical preponderance of lactic acid bacteria, which by the 12th day make up the entire mass of bacteria existing in the silage. This is due to the provision of these cultures with mono and disaccharides, which are most suitable for the nutrition and existence of lactic acid bacteria. If all technological methods are followed, as a result of rapid biochemical transformations in the initial period of storage, corn silage (both in pure form and with the addition of straw) fully matures on the 15th day from the moment of laying.

Many monosaccharides (glucose, levulose, galactose, mannose) are fermented, as a rule, by all lactic acid bacteria.

The general equation of lactic acid fermentation is С6Н12О6 = 2СН3СНОН · СООН glucose lactic acid is a total one, summarizing a number of complex transformations of carbohydrates and their decay products, which step by step take place in a microbial cell.

Certain types of lactic acid bacteria have the ability to use pentoses (xylose, arabinose) and, in particular, rhamnose (methylpentose).

Disaccharides (sucrose, maltose, lactose) are usually assimilated selectively. Some lactic acid bacteria ferment some carbohydrates while others ferment others. In nature, however, there are lactic acid bacteria that can assimilate and ferment a fairly wide range of disaccharides.

Polysaccharides (dextrins, starch, inulin) can be fermented only by single, recently described forms of lactic acid bacteria. The plant mass contains levulesan polysaccharides, which play the role of reserve substances. They are relatively easy to hydrolyze and, according to available preliminary data, are likely to be fermented by some lactic acid bacteria.

Fiber is not used by lactic acid bacteria. Its reserve in the silage remains unchanged.

The composition of the end products of fermentation changes quite strongly if not hexose is fermented, but pentose, that is, sugar with five carbon atoms: fermentation products with two and three carbon atoms (lactic and acetic acids) are formed.

In this case, the fermentation process can be expressed by the following approximate equation:

6C5H10O5 = 8C3H6O3 + 3C2H4O2.

pentose lactic acetic acid acid Plant raw materials contain pentosans, which give pentose during hydrolysis. Therefore, it is not surprising that even with normal maturation of silage, a certain amount of acetic acid usually accumulates in it.

According to the composition of fermentation products, lactic acid bacteria are currently divided into two main groups:

1) homofermentative - forming from sugars, except for lactic acid, only traces of by-products;

2) heteroenzymatic - forming from sugars, in addition to lactic acid, noticeable amounts of carbon dioxide and other products.

The known biochemical characteristics of the above groups of lactic acid bacteria are given in table. 13, which indicates the accumulating basic products of their vital activity.

Table 13. Fermentation products of lactic acid bacteria formed from carbohydrates

- & nbsp– & nbsp–

As can be seen from the table, homofermentative lactic acid bacteria, in contrast to heteroenzymatic, form very small amounts of volatile acid (acetic), alcohol and carbon dioxide.

The energy loss during the fermentation of glucose by homoenzymatic lactic acid bacteria is 2-3%, and the yield of lactic acid is 95-97%.

The intensity of the formation of lactic acid formed by lactic acid bacteria can be significantly influenced not only by the composition of the medium (the chemical composition of the plant mass laid on silage, haylage), but also by other conditions (acidity of the medium, temperature, aeration, etc.).

2.5.2. Influence of acidity of the medium on the rate of acid accumulation

At different meanings pH intermediate reactions that take place during fermentation take different directions. If the resulting lactic acid is neutralized, then during the development of homofermentative lactic acid bacteria, significant amounts of acetic acid and other by-products (up to 40% of the fermented sugar) will accumulate on the hexoses.

The results of many researchers have shown a decrease in lactic acid in silage with increasing pH. Thus, in the group of samples with a pH above 5.0, a low content of lactic acid was observed, and its ratio with acetic acid was 1: 1.

Due to the fact that lactic acid bacteria produce a significant amount of acids as a result of their vital activity, they develop at a rather low pH value.

The group of lactic acid bacteria includes both coccoid and rod-shaped forms.

Rod-shaped forms tolerate lower acidity.

This property of lactic acid sticks explains the fact of their accumulation by the end of ensiling, when the feed is largely acidified.

Comparison of the materials of various researchers shows that for the same forms of lactic acid bacteria, not identical values of the critical pH value are indicated. This is not surprising, since the position of the cardinal points of pH is affected by the composition of the acids that determine the reaction of the medium, as well as the components of the substrate in which the bacteria develop. Therefore, for example, the minimum pH points for a bacterium will not be the same in two different environments. Thus, acetic acid, less dissociated, but more harmful to microorganisms, stops the development of lactic acid bacteria at a higher pH value than lactic acid.

2.5.3. Influence of temperature on the energy of acid formation of lactic acid bacteria The vital activity of lactic acid bacteria can successfully proceed both in relatively cold and in self-heating silos.

Certain species and races of lactic acid bacteria can develop under quite different temperature conditions. Their most common representatives live in the range from 7–10 to 10–42 ° С, with an optimum of about 25–30 ° С.

In fig. 1 shows the indicator of the vital activity of one of the races of lactic acid bacteria, which are quite often found in silage fodder, - the energy of acid formation at different temperatures.

Rice. 1. Influence of temperature on the energy of acid formation of lactic acid bacteria In nature, however, there are frequent forms of lactic acid bacteria capable of multiplying both in the zone of higher and lower temperatures.

For example, in silos ripened in winter at a very low above-zero temperature, streptococci with a minimum temperature point below 5 ° C are found. Their optimum is about 25 ° C, and the maximum is about 47 ° C. At a temperature of 5 ° C, these bacteria still quite vigorously accumulate lactic acid in the feed.

At low temperatures, not only coccoid, but also rod-shaped forms of lactic acid bacteria can develop.

In self-heating silos, it was also possible to find, along with lactic acid sticks, and cocci. The minimum temperature point of cocci capable of developing at elevated temperatures is about 12 ° C, of rods - about 27 ° C. The temperature maximum of these forms approached 55 ° С, and the optimum lies in the range 40–43 ° С.

Lactic acid bacteria develop poorly under extreme conditions - at temperatures above 55 ° C, and with a further increase in temperature they die as forms that do not form spores. The nature of the influence of different temperatures on the accumulation of lactic acid in a silage from cereal grasses is shown in Fig. 2.

Rice. 2. Influence of temperature on acid accumulation in grass silage As can be seen, at a temperature of 60 ° C, the accumulation of lactic acid is strongly suppressed.

Some researchers note that lactic acid accumulates in silos when they are heated even above a temperature of 60–65 ° C. In this regard, it should be borne in mind that it can be produced not only by lactic acid bacteria.

Other bacteria also produce some amount of lactic acid. In particular, it is formed in the environment during the development of some spore-bearing rods belonging to the You group. subtilis and multiplying at elevated temperatures.

Such forms are always richly presented in self-heating silos.

2.5.4. Effect of aeration on the activity of lactic acid bacteria

Lactic acid bacteria are conditional facultative anaerobes, that is, they can live both in the presence of oxygen and in anaerobic conditions. The degree of oxygen supply to the environment can be characterized by the value of the redox (OR) potential (Eh). Sometimes the OB-potential is expressed by the value of rH2, calculated by the formula Eh (in millivolts) rH2 = + 2pH.

The value of rH2 shows the negative logarithm of the concentration of hydrogen molecules, expressed in atmospheres. It is quite obvious that the degree of oxygen supply is directly related to the concentration of hydrogen molecules in the medium, which indicates the degree of its reduction.

In an oxygen atmosphere, with its neutral reaction, the value of Eh is 810, and rH2 = 41. In a hydrogen atmosphere, respectively, Eh = –421, and rH2 = 0. Fluctuations of the values noted characterize one or another degree of aerobicity. In an environment where lactic acid bacteria develop, the potential can decrease rather low, to a value of rH2 5.0–6.0.

Thus, lactic acid bacteria do not need oxygen. They are so adapted to obtaining the necessary energy with the help of the fermentation process that even with the access of air, they do not switch to breathing and continue to cause the fermentation process.

This is due to the lack of an enzyme system in lactic acid bacteria that provides respiration (hemin enzyme, catalase, etc.).

True, there are isolated facts indicating the ability of some pathogens of the lactic acid process to exist under aerobic conditions due to respiration.

It is possible that similar forms of bacteria are found, but they are an exception.

The literature contains data on the oxidation of lactic acid by individual lactic acid bacteria under aerobic conditions. Due to this, in cultures of such microorganisms, acidity decreases over time. Considerations of this kind are hardly solid.

In densely packed silage forage, lactic acid bacteria can multiply intensively, while the vast majority of putrefactive bacteria and mold are clearly depressed.

If oxygen is available to the silage mass, then lactic acid is destroyed by yeast, molds and other aerobic bacteria.

In this case, the acidity of the silage decreases, putrefactive processes begin to develop in it and the feed deteriorates (Fig. 3).

- & nbsp– & nbsp–

In fig. 3 shows that aerobic conditions promoted the decomposition of lactic acid in silage from forage cabbage. This feed was spoiled, since the preservative factor - lactic acid - ceased to act on unwanted microflora, which remained in a passive state in the feed mass.

2.5.5. Effect of increased osmotic pressure of the medium on the development of lactic acid bacteria Information on the resistance of lactic acid bacteria to increased osmotic pressure of the medium is limited. From the available information, it follows that different types of these microorganisms have different attitudes towards the presence of sodium chloride in the environment, including sometimes adaptation to high salt concentrations.

Detailed studies of the physiology of lactic acid bacteria, carried out under the leadership of E.N. Later studies established that cultures of lactic acid bacteria in haylage are more osmophilic than cultures isolated from silage. They withstood the concentration of sodium chloride from 7 to 10%, while silage lactic acid bacteria - up to 7%. At the same time, already at 6% salt content in the medium, the morphology of the cells begins to change: the shape is lengthened, swelling is observed at the ends of the cell, curvatures in the center and around the periphery, and some of their vital functions are disrupted. This is due to dehydration and it is difficult for cells to consume nutrients from environment.

Microorganisms are exposed to approximately the same conditions during haylage harvesting. Cultures of lactic acid bacteria in haylage, having adapted to the high osmotic activity of cell sap (50 atm. At 40–45% grass moisture), have a higher ability to survive than lactic acid bacteria of silage, putrefactive microorganisms, yeast.

Thus, the osmotic activity of lactic acid bacteria cultures in haylage is a factor that ensures their dominant position in the preparation and further storage of feed with low moisture content. If the moisture content of the canned mass is below 50-60%, then it will be well preserved even with a deficiency of water-soluble carbohydrates.

In cultures of lactic acid bacteria in haylage and silage, not only osmotic activity differs, but the activity of reproduction and accumulation of lactic acid, as well as the ability to ferment starch, arabinose, xylose. The maximum number of microorganisms in variants with a dried mass was revealed on the 15th day, while in the variants of silage from freshly cut plants - on the 7th day.

However, in a production environment, it is not easy to achieve high dry matter content in grass cuttings due to weather conditions. Therefore, for a number of years, scientists have been looking for biological products that could have a positive effect on the quality of canned feed made from freshly cut and wilted grasses. When ensiling wilted grasses, only special osmotolerant lactic acid bacteria should be used.

2.6. Butyric acid bacteria

Butyric acid bacteria (Clostridium sp.) Are spore-forming, mobile, rod-shaped anaerobic butyric acid bacteria (Clostridia), widespread in the soil. The presence of Clostridia in silage is a result of soil contamination, since their numbers on green mass of forage crops are usually very low. Almost immediately after filling the storage with green mass, butyric acid bacteria begin to multiply intensively together with lactic acid bacteria in the first few days.

High plant moisture, due to the presence of plant cell sap in the crushed silage mass, and anaerobic conditions in the silo are ideal conditions for the growth of Clostridia. Therefore, by the end of the first day, their number increases and further depends on the intensity of lactic acid fermentation.

In the case of a weak accumulation of lactic acid and a decrease in the pH level, butyric acid bacteria multiply vigorously and their number reaches a maximum (103–107 cells / g) in a few days.

As the moisture content increases (with a content of 15% dry matter in the silage mass), the sensitivity of Clostridia to the acidity of the medium decreases even at pH 4.0.

It is difficult to pinpoint the exact critical pH value of the silage at which clostridial inhibition begins, since it depends not only on the amount of lactic acid formed, but also on the water in the feed and the temperature of the environment.

Clostridia are sensitive to lack of water. It has been proven that with an increase in free water, the sensitivity of these bacteria to the acidity of the environment decreases.

Feed temperature has a marked effect on clostridial growth. The optimum temperature for the growth of most of these bacteria is around 37 ° C.

Clostridial spores are characterized by high thermal stability.

Therefore, butyric acid bacteria can persist for a long time in the silage in the form of spores, and when they enter conditions favorable for their development, they begin to multiply. This explains the discrepancy in the biochemical and microbiological parameters of the silage: butyric acid is absent, and the titer of butyric acid bacteria in the same feed samples is high.

The study of butyric acid fermentation products in silage showed that there are two physiological groups: saccharolytic and proteolytic clostridia.

Sugarolytic clostridia (Cl. Butyricum, Cl. Pasteurianum) ferment mainly mono- and disaccharides. The amount of the products formed is varied (butyric, acetic and formic acids, butyl, ethyl, amyl and propyl alcohols, acetone, hydrogen, and carbon dioxide) and varies greatly. This is due to the species of microorganisms, substrate, pH level, temperature. The ratio of carbon dioxide and hydrogen is usually 1: 1. It is believed that butyric acid results from the condensation of two acetic acid molecules. The direct formation of butyric acid cannot serve as an energy source for clostridia. To maintain their vital activity, acetic acid is needed, which is formed during the oxidation of acetaldehyde as a result of decarboxylation of pyruvic or lactic acid.

Cl. butyricum, Cl. tyrobutyricum, Cl. Papaputrificum. Silage with a predominance of these Clostridia usually contains almost no lactic acid and sugar. Mostly butyric acid is present, although acetic acid can often be abundant.

C6H12O6 = C4H8O2 + 2CO2 + 2H2.

butyric sugar carbon dioxide - hydrogen acid gas 2С3Н6О3 = С4Н8О2 + 2СО2 + 2Н2.

lactic butyric carbonic acid acid lactic gas Proteolytic clostridia ferment mainly proteins, but also amino acids and amides. As a result of amino acid catabolism, volatile fatty acids are formed, among which acetic acid predominates. A significant participation of proteolytic Clostridia in the decomposition of carbohydrates was also revealed. Proteolytic Clostridia of the Cl species are found in silos. sporogenes, Cl. acetobutyricum, Cl. Subterminale, Cl. bifermentas. The amount of butyric acid in silage is a reliable indicator of the extent of clostridial activity.

Butyric acid fermentation results in high nutrient losses as a result of protein, carbohydrate and energy catabolism.

Energy is lost 7–8 times more than during lactic acid fermentation. In addition, the silage reaction shifts to the neutral side due to the formation of alkaline compounds during the breakdown of protein and lactic acid. The organoleptic characteristics of the feed deteriorate due to the accumulation of butyric acid, ammonia and hydrogen sulfide. When cows are fed with such silage, clostridial spores with milk enter the cheese and, germinating in it under certain conditions, can cause it to "swell" and turn rancid.

Thus, the following basic physiological and biochemical features are characteristic of causative agents of butyric fermentation:

1) butyric acid bacteria, being obligate anaerobes, begin to develop under conditions of strong compaction of the silage mass;

2) decomposing sugar, they compete with lactic acid bacteria, and using proteins and lactic acid, lead to the formation of strongly alkaline decomposition products of protein (ammonia) and toxic amines;

3) butyric acid bacteria need moist plant raw materials for their development, and at high humidity of the initial mass, they have the greatest chances to suppress all other types of fermentation;

4) optimum temperatures for butyric acid bacteria fluctuate within 35–40 ° С, but their spores tolerate higher temperatures;

5) butyric acid bacteria are sensitive to acidity and cease their activity at a pH below 4.2.

Effective measures against causative agents of butyric acid fermentation are rapid acidification of the plant mass, drying of wet plants. There are biological preparations based on lactic acid bacteria to activate lactic acid fermentation in silage. In addition, chemicals have been developed that have a bactericidal (suppressive) and bacteriostatic (inhibitory) effect on butyric acid bacteria.

2.7. Putrefactive bacteria (Bacillus, Pseudomona)

Representatives of the genus Bacillus (Bac. Mesentericus, Bac. Megatherium) are similar in their physiological and biochemical characteristics to representatives of Clostridia, but, unlike them, are able to develop under aerobic conditions. Therefore, they are one of the first to be included in the fermentation process and are most often found in an amount of 104-106, but in some cases (for example, in violation of technology) - up to 108-109. These microorganisms are active producers of various hydrolytic enzymes. They use various proteins, carbohydrates (glucose, sucrose, maltose, etc.) and organic acids as nutrients.

A significant part of protein nitrogen (up to 40% and more) under the action of bacilli can be converted into amine and ammonia forms, and part of amino acids into mono- and diamines, especially under conditions of slow acidification of the mass. Decarboxylation has its maximum in an acidic environment, while deamination occurs in a neutral and alkaline environment. Amines can be produced during decarboxylation. Some of them have toxic properties (indole, skatole, methyl mercaptan, etc.), and when feeding silage, these substances, entering the bloodstream, cause various diseases and poisoning of farm animals. Some types of bacilli ferment glucose to form 2,3-butylene glycol, acetic acid, ethyl alcohol, glycerin, carbon dioxide, and trace amounts of formic and succinic acids.

An important property of putrefactive bacteria, which is important for the processes occurring in the forage mass, is their ability to sporulate. Bacillus bacteria have been found in some decayed silos, especially corn silage. They are, apparently, inherent in silage, and not brought in from the outside (with air). After long-term storage, bacilli are isolated from many silos, although they are almost not found in the original grass.

Based on this, it was suggested that some putrefactive bacteria can develop from spores under anaerobic conditions.

Thus, based on the foregoing, the main features for causative agents of putrefactive fermentation are as follows:

1) putrefactive bacteria cannot exist without oxygen, therefore, putrefaction is impossible in a sealed storage;

2) they decompose primarily protein (to ammonia and toxic amines), as well as carbohydrates and lactic acid (to gaseous products);

3) putrefactive bacteria multiply at a pH above 5.5. With slow acidification of the feed, a significant part of the protein nitrogen passes into the amine and ammonia forms;

4) an important property of putrefactive bacteria is their ability to sporulate. In the case of long-term storage and feeding of silage, in which yeast and butyric acid bacteria will decompose most of the lactic acid or it will be neutralized by protein decomposition products, putrefactive bacteria, developing from spores, can begin their destructive activity.

The main condition for limiting the existence of putrefactive bacteria is fast filling, good ramming, reliable sealing of the silo. Losses caused by pathogens of putrefactive fermentation can be reduced by using chemical preservatives and biological products.

2.8. Molds and yeast

Both of these types of microorganisms belong to fungi and are very undesirable representatives of the microflora of silage, they easily tolerate the acidic reaction of the environment (pH 3.2 and below). Since molds (Penicillium, Aspergillus, etc.) are obligate aerobes, they begin to develop immediately after the storage is filled, but with the disappearance of oxygen, their development stops.

In a properly filled silo with sufficient compaction and sealing, this occurs within a few hours. If there are foci of mold in the silo, it means that the air displacement was insufficient or the sealing was incomplete. The risk of mold growth is especially great in silage of dried plant material, since such feed, especially its upper layers, is very difficult to compact. Reliable sealing is practically unattainable in land-based heaps. Almost 40% of the silage is moldy; the food has a decomposed, smeared structure and becomes unsuitable for feeding to animals.

Yeast (Hansenula, Pichia, Candida, Saccharomyces, Torulopsis) develops immediately after filling the storage facilities, as they are facultative anaerobes and can develop with negligible amounts of oxygen in the silage. In addition, they are highly resistant to temperature factors and low pH levels.

Yeast fungi stop their development only in the complete absence of oxygen in the silo, but small amounts of them are found in the surface layers of the silo.

Under anaerobic conditions, they use simple sugars (glucose, fructose, mannose, sucrose, galactose, raffinose, maltose, dextrins) along the glycolytic pathway and develop through the oxidation of sugars and organic acids:

C6H12O6 = 2C2H5OH + 2CO2 + 0.12 MJ.

sugar alcohol carbon dioxide The full use of sugars and organic acids leads to the fact that the acidic environment of the silage is replaced by an alkaline one, favorable conditions are created for the development of butyric acid and putrefactive microflora.

During alcoholic fermentation, large energy losses are observed.

If during lactic acid fermentation 3% of sugar energy is lost, then during alcoholic fermentation - more than half. Under aerobic conditions, the oxidation of carbohydrates by yeast leads to the production of water and CO2. Some yeast use pentoses (D-xylose, D-ribose), polysaccharides (starch).

The negative effect of yeast in secondary fermentation is that it develops due to the oxidation of organic acids, which occurs after complete fermentation with access to air. As a result of the oxidation of lactic and other organic acids, the acidic reaction of the medium is replaced by an alkaline one - up to pH 10.0.

As a result, the quality of silage from corn, as well as from "deeply" wilted grasses, that is, forage with the best indicators for fermentation products, decreases.

Based on the above, molds and yeasts can be characterized as follows:

1) molds and yeasts are undesirable representatives of the aerobic microflora;

2) the negative effect of molds and yeasts is that they cause oxidative breakdown of carbohydrates, proteins and organic acids (including lactic acid);

3) molds and yeasts easily tolerate the acidic reaction of the environment (pH below 3.0 and even 1.2);

4) mold fungi release toxins hazardous to the health of animals and humans;

5) yeast, being the causative agent of secondary fermentation processes, leads to aerobic instability of silos.

Restricting air access through quick setting, tamping and sealing, and proper digging and feeding are decisive factors in limiting the development of mold and yeast. To suppress the development of pathogens of secondary fermentation, preparations with fungistatic (fungicidal) activity are recommended.

Summarizing the above, microorganisms in silage can be divided into beneficial (lactic acid bacteria) and harmful (butyric acid, putrefactive bacteria, yeast and molds).

Based on the physiological and biochemical characteristics of microorganisms found in the silo, rapid decline pH (up to 4.0 and less) inhibits the multiplication of many unwanted microorganisms.

In such a pH range, along with lactic acid bacteria, only molds and yeasts can exist. But they require oxygen. Therefore, for successful ensiling, it is necessary to remove air from the storage as quickly as possible through reliable ramming and quick filling of the storage, proper cover. This provides favorable conditions for lactic acid bacteria (anaerobes).

In the ideal case, namely, with a sufficient content of water-soluble carbohydrates in the initial plant material and anaerobic conditions, lactic acid fermentation takes a dominant position. In just a few days, the pH reaches its optimum level, at which unwanted types of fermentation cease.

When ensiling forage plants rich in protein, it is necessary to wilt them out or use chemical and biological preservatives that suppress (inhibit) the development of undesirable microorganisms and make it possible to obtain a good-quality forage regardless of the silage capacity and moisture content of the original plant material.

During storage, feed raw materials and feed are a favorable breeding ground for the rapid growth of mold. Due to temperature changes during the day and at night, moisture migrates in the storage facilities, which contributes to the accelerated growth of mold and the reproduction of insects.

Fodder affected by mold and insects are poorly eaten by farm animals and poultry, cause suppression of the circulatory and immune systems, and disrupt the functioning of the kidneys. Ultimately, the health and productivity of animals and poultry deteriorates, the costs of their maintenance and treatment increase, and the economic efficiency of animal husbandry decreases. It is known that animals eat moldy hay very reluctantly or do not eat it at all. Moldy silage and haylage are also unsuitable as forage. Poisonous toxins released by some fungal crops are found in silage from ground piles and earthen silos or in the upper layers of the forage mass of large silo trenches with poor compaction and leaky cover of freshly cut and especially dried mass.

Fungi use many nutrients for their own growth. As a result of the vital activity of a colony of 40,000 fungi, the content of nutrients in feed decreases by 1.5–1.8% in one week; there is a deterioration in taste, since infection of the grain with some types of fungi leads to the appearance of a characteristic repulsive mold smell and an unpleasant taste.

The physical properties of feed raw materials change, which is manifested in the formation of dense lumps, which impede its transportation and lead to acidification of grain in silos; in the presence of mycotoxins, leading to poor health, growth retardation of animals and a decrease in their productivity.

Different molds produce different mycotoxins, some of which produce several mycotoxins: Penicillium - ochratoxins; Fusarium - T-2 toxin, zearalenone, DON; Aspergillus - aflatoxins, ochratoxins. In this case, their negative effect is greatly enhanced.

Mycotoxins are not destroyed during heat treatment of feed and, getting into the body of animals with feed, accumulate in meat, eggs, milk. Therefore, their presence in feed poses a great danger not only to animals, but also to human health, since some of the mycotoxins, in particular aflatoxins, are carcinogenic and their ingestion should be absolutely excluded.

For the growth of molds, a number of conditions are necessary:

1) temperature. The optimum temperature for the growth of molds is in the range of 18-30 ° C. Nevertheless, some of their species grow and multiply intensively at temperatures of 4–8 ° C;

2) humidity.

To reduce the moisture content in grain, producers are forced to dry it to the specified values. This is energy and labor intensive over an extremely limited period of time. However, even when storing grain with a standard moisture content, a factor such as moisture migration has a negative effect on the quality of grain during storage.

So, when storing grain, which has an initial moisture content of about 13%, moisture migration occurs, caused by the temperature difference between the top (35 ° C) and the bottom (25 ° C) of the storage. A month later, the moisture content of the grain at the bottom was 11.8%, and at the top - 15.5%. In the process of storing grain of normal moisture in some areas, optimal conditions are often formed for the rapid growth of mold.

There is strong medical evidence of lung disease in animals and workers handling moldy hay and grain. In both humans and animals, they are caused by inhalation of thermophilic microorganisms (Micropolispora, Тhermo-actinomyces, Aspergillus).

According to the World Health Organization, about 25% of the world's grain supply is contaminated with mycotoxins, so it is important to deal with their source - mold.

There are many other potentially harmful molds that can cause a range of mycotoxicosis, including reduced fertility, abortion and general deterioration health. All these diseases are caused by mycotoxins produced by the following fungi: Aspergillus, Fusarium, Penicillium (aflatoxins, ceralenone, ochratoxin).

The main reason for the decrease in the quality of compound feed is their infection with molds and subsequently contamination with mycotoxins.

Fungi enter the compound feed mainly with grain and products of its processing, partly it is additionally seeded in the process of manufacturing, transportation and storage. Being a dead substrate, very accessible for microorganisms, feed is more likely than grain to be attacked by fungi. This is facilitated by its high hygroscopicity, as well as a rich supply of nutrients, especially in connection with its enrichment with vitamins, microelements and other additives.

Due to the growth and reproduction of molds in the compound feed, the following occurs:

A decrease in its energy and nutritional value, since fungi use the nutrients of the feed affected by them for their vital activity;

Deterioration of palatability, since even a small amount of mold in the feed creates dust, unpleasant odors and tastes, which is the reason for poor feed intake by animals;

Changes in the physical parameters of compound feed, manifested in the release of additional amounts of water by the fungi and in the caking of the feed as a result of the growth of the mycelium of the fungi;

Infection of feed with mycotoxins, produced by fungi, which leads to a growth retardation of animals, a decrease in their productivity, feed conversion and causes permanent poisoning of the entire livestock population.

Compound feed, consisting of crushed grain, bran, is a fertile soil for the germination of mold. The longer the shelf life of raw materials, finished compound feed, the greater the risk of mold damage. Under favorable conditions, a significant multiplication of fungi can occur in a very short time, myceliums of fungi grow by 1 mm in 1 hour, therefore it is necessary to carry out preventive treatment with antifungal drugs, which is more economically justified than fighting fungi and mycotoxins in already moldy feed.

The most practical and reliable way to protect feed from mold is to use preparations based on organic acids and their salts. They inhibit the growth of microorganisms by acidifying the cytoplasm of the cell, which leads to cell death. Propionic acid is a recognized mold inhibitor. However, the use of pure propionic acid is associated with a number of difficulties: the acid strongly corrodes metal parts of machines and mechanisms, has a pungent pungent odor, volatility and can lead to serious burns of personnel working with it and corrosion of metal parts of conveyors and mixers. The liquid propionic acid in the mildew inhibitor microform is contained in a buffer complex specially developed by Franklin (Holland), which allows the drug to be used without damage to equipment and personnel. The liquid propionic and phosphoric acids that are part of the micoform have a certain level of activity against molds, yeasts and bacteria. Each of these acids has its own advantages and disadvantages in terms of the spectrum of microorganisms inhibited, ease of handling and cost. Used together in optimal proportions, these organic acids retain their advantages and compensate for individual disadvantages.

3. SCALE OF LOSSES IN CANNED FEEDS,

CAUSED BY THE ACTIVITIES OF MICROORGANISMS

When compiling a feed balance, it is necessary to take into account losses during the preparation and storage of canned feed. There are many diagrams showing that total losses are the sum of losses in the field, storage facilities and occur even during the harvesting of green mass.

This lecture examines the magnitude of losses caused by the activity of microorganisms, which are often underestimated and, with unskilled work, can reach enormous proportions.

3.1. Fermentation loss

After the death of plant cells in a filled and well-compacted storage facility, intensive decomposition and transformation of nutrients by multiplying microorganisms begins. Losses occur as a result of the formation of fermentation gases ("waste"), losses in the upper and side layers, losses due to secondary fermentation processes.

Continuous filling of storage facilities (silo, haylage) can significantly reduce the formation of gases. With a fast filling of the storage, the loss of dry matter due to "waste" can be 5–9%. With extended filling, the corresponding indicators can reach 10-13% or more. Consequently, by continuous filling it is possible to reduce waste from waste by about 4–5%.

It should be borne in mind that in poorly compacted haylage as a result of self-heating processes, the protein digestibility is halved.

Intensive decomposition of nutrients occurs in the upper and lateral layers in the uncovered silage (hay) mass. With the cover of one chaff or without cover, the losses can be much greater. Mold fungi, when they develop, initiate a strong decomposition of protein. Protein breakdown products are alkaline and bind lactic acid. Direct decomposition of lactic acid also occurs. These processes lead to an increase in the pH level and a deterioration in the quality of the feed. Even if at the moment of opening the storage the thickness of the spoiled layer does not exceed 10 cm, it should be borne in mind that this layer was originally 20-50 cm thick, and the silage under the spoiled layer is characterized by a high pH level, contains toxic toxins and is not suitable for feeding animals.

Losses caused by secondary fermentation processes can reach 20–25%. It has been established that the first stage of silage spoilage is caused by yeast together with aerobic bacteria; it is associated with its warming up and a decrease in acidity. In the second stage of silage spoilage, subsequent mold infestation occurs. Such feed is considered unsuitable if it contains more than 5 × 105 mushrooms. Already after 5 days of aerobic storage in the case of long-term feeding or improper removal from storage, corn silage, even with a good initial pH of 4.1, but already having 3 × 107 yeast, is characterized astronomically high number yeast and mold Streptomycetcn.

3.2. Fodder mycotoxicosis

Among the many environmental factors toxic substances- mycotoxins, formed by microscopic fungi, have recently attracted more and more attention.

Mycotoxins are toxic metabolic products of molds that form on the surface of food and feed. Toxigenic fungi are extremely widespread in nature, and under favorable conditions (high humidity and temperature), they can infect various food, feed, industrial substances and cause significant damage to the national economy. Consumption of food and feed contaminated (contaminated with microorganisms) with these fungi and mycotoxins can be accompanied by severe diseases of humans and farm animals - mycotoxicosis.

Recently, the problem of mycotoxicosis has become large. In the Republic of Belarus, as in the whole world, a significant part of the produced grain is contaminated with mycotoxins, which not only negatively and destructively affect the animal body, significantly reducing the parameters of productivity, the quality of the products, increasing economic costs, but also pose a serious danger to human health.

The consumption of contaminated feed by poultry leads to the occurrence of chronic mycotoxicosis, characterized by a wide range of damage to the liver, kidneys, gastrointestinal tract, respiratory organs, nervous system, which ultimately negatively affects the productivity and safety of livestock. The widespread prevalence of this negative requires finding new ways to solve this problem.

Mycotoxicoses are diseases that occur when animals eat plant feed that are affected by toxin-forming fungi. Mycotoxicoses are not infectious diseases; when they occur in the body of animals, immunological restructuring does not occur and immunity does not develop. All types of animals, birds and fish can be exposed to mycotoxicosis, and people also get sick.

The total number of fungi species in the world microflora ranges from 200 to 300 thousand species, toxigenic - from 100 to 150 species. The greatest danger to animals and humans is posed by feed and foodstuffs contaminated with fungal metabolites, which belong to two groups.

The first group is the so-called soprophyte mushrooms (warehouse mushrooms) of the genera Aspergillus and Penicillium. These are mainly fungi that are not able to infect vegetative plants and get into cereals, roughage and food mainly during the period of their harvesting, storage and preparation for feeding.

A certain substrate specificity of toxic-forming mycomycetes has been noted: species of the genus Fusarium mainly affect cereal grains; Aspergillus - pulses and feed ingredients; Stachibotrys altemans, Dendrodochium toxicum attack roughage.

The development of mycotoxin-producing fungi requires certain conditions. Ergot and smut affect plants during the growing season. Sclerotium in soil develops at a temperature of 22–26 ° C and a humidity of 25–30%. Temperature and humidity are critical factors in the growth and reproduction of toxic fungi. The optimum humidity is 25-30%, the most favorable temperature is 25-50 ° C. Roughage (hay with a moisture content of 16%, straw - 15% during storage) are not affected by fungi.

Roughage with high humidity self-warms (this is facilitated by microorganisms), and favorable conditions for the development of mycomycetes are created in them.

Not only roughage is subjected to self-heating, but also grain, as well as its processed products (flour, compound feed, bran, grain waste, etc.).

The isolation and study of mycotoxins is very important. According to many scientists, from 80 to 2,000 different mycotoxins have been isolated and named, of which 47 are highly toxic and 15 with carcinogenic and mutagenic properties (aflatoxins B and M, ochratoxin A, zearalenone, T-2 toxin, patulin, cyclopiazonic and penicillic acids and some others). Naturally excreted aflatoxins, ochratoxin A, patulin, T-2 toxin, penicillic acid, etc.

The overwhelming majority of mycotoxins are exotoxins, i.e.

released into the substrate on which the mushroom grows. Mycotoxins can remain in feed for a long time after the death of the fungus that formed them. Therefore, the appearance of the feed may not always serve as a criterion for its safety. Mycotoxins are low molecular weight compounds. They are resistant to high temperatures, do not deteriorate during processing with hot steam, drying, long-term storage, the action of acids and alkalis. The macroorganism does not produce antibodies against them, that is, animals and humans remain sensitive to mycotoxins throughout their lives.

The most common mycotoxicosis among animals are aspergillotoxicosis, stachybotriotoxicosis, fusariotoxicosis, dendrodochiotoxicosis, myrothecytoxicosis, clavacenstoxicosis, penicillotoxicosis, rhizopusotoxicosis, and toxicosis caused by smut fungi.

Their chemical formulas, physicochemical properties, mechanism of action have been determined; some countries have calculated minimum permissible concentrations of these mycotoxins in feed for different types farm animals and poultry; and also developed quantitative laboratory methods for the determination of these substances in various substances. Other less studied mycotoxins are being studied, such as ergotoxins, etc., which also cause significant damage to livestock and poultry farming.

It is a well-known fact that mycotoxins administered in a chemically pure form exhibit toxic properties to a much lesser extent than the same amounts of mycotoxin, but produced in natural conditions. This is due to the fact that microscopic fungi in the process of their vital activity produce various toxins, the number of which can reach several dozen, and these toxins exhibit a combined toxic effect.

Laboratories can only detect a small fraction of the mycotoxins already known. The synergistic effect of mycotoxins has been studied to a minimal extent, although in practice it is of great importance.

The difficulty lies in the uniqueness and unpredictability of quality and quantitative composition mycotoxins synthesized by different types of fungi under different conditions.

The cumulative properties of mycotoxins are also known. In the presence of mycotoxins in feed in quantities below the sensitivity level of the determination method, there is an illusion of their absence and, accordingly, feed safety. However, within several days of feeding such feeds as a result of cumulation, the dose of toxins obtained reaches a critical and manifests itself in some way, mainly a decrease in appetite, general depression, indigestion, etc. In the overwhelming majority of cases, the cause of these symptoms will be looked for in anything. but not in the action of mycotoxins.

Another possible development of events that can go unnoticed for a long time: mycotoxins, accumulating, will gradually destroy the immune system of an animal or bird. This effect is typical for almost all mycotoxins, but its detection without the use of special methods is practically impossible. A similar picture is observed when toxins are found in feed in maximum permissible concentrations. These results indicate a real possibility of the presence of many other mycotoxins in feed, which are not able to detect laboratory studies.

Mycotoxins have one thing in common - they are biocides that destroy living cells. For other properties, including physicochemical, mycotoxins differ very significantly, this is what makes it impossible to develop a single effective method fight against them.

The most common method today is the adsorption of mycotoxins by adsorbents of organic or inorganic origin. The method is based on the physical properties of mycotoxin molecules - their polarity and molecular size. Therefore, adsorbents of different nature adsorb mycotoxins in different ways.

The method of adsorption effectively removes polar mycotoxins (these are mainly aflatoxins, to some extent fumonisins).

At the same time, non-polar toxins are practically not sorbed by some adsorbents, while others are not adsorbed efficiently enough.

The degree of neutralization of mycotoxins also depends on the adsorption capacity of the adsorbent. This indicator and the degree of infestation of the feed determine the rate of introduction of the adsorbent into the feed. The essential properties of adsorbents are the ability to work in a wide pH range and the irreversibility of the binding of mycotoxins. It is known that mycotoxins can be adsorbed onto an adsorbent in the stomach and desorbed when the intestine is alkaline. As a result, the effectiveness of such an adsorbent will be questionable. Some adsorbents also have the ability to adsorb nutrients, vitamins, and trace elements.

There are difficulties in assessing the effectiveness of adsorbents, which greatly complicates their selection and obtaining objective results. Most of the classical in vitro methods cannot even come close to the real conditions of the gastrointestinal tract.

In vivo experiments are too complex and difficult to reproduce.

Therefore, the search continues for models that would make it possible to reproduce conditions as close as possible to nature and to obtain more objective results.

Most leading toxicologists believe that effective control of mycotoxins is possible using only a few complementary methods of their elimination from feed, which have different mechanisms of action and are directed against different groups of toxins. Research in this area is very intensive. The search continues for optimal inorganic and organic adsorbents.

At present, hydrated sodium, calcium, and aluminosilicates have been created, which are recognized as the best inorganic adsorbents. This has been proven by laboratory and industrial research of many independent research centers.

A new direction is the neutralization of mycotoxins. Neutralization of the toxic effect of mycotoxins by enzymes is a natural way for microorganisms to fight for existence. Numerous studies have shown that it is excellent for neutralizing mycotoxins in the body of farm animals and poultry.

Specially selected enzymes modify mycotoxins to harmless substances by acting on the part of the molecule that is responsible for the toxic effect. This approach is especially important and, perhaps, the only effective one for non-polar mycotoxins, which practically do not bind by adsorbents (trichothecenes, zearalenone, ochratoxins).

4. MICROBIOLOGICAL ANALYSIS OF FEEDS

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"The program of the discipline" Biology "Authors: prof. G.N. Ogureeva, prof. V.M. Galushin, prof. A.V. Bobrov The objectives of mastering the discipline are: obtaining fundamental knowledge about the organization of living organisms and the peculiarities of their functioning; get it ... "

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EPIPHYTIC MICROFLORA OF GRAIN AND ITS CHANGE DURING STORAGE OF FOOD
A variety of microflora lives on the surface of the grain. Part of microorganisms comes from the rhizosphere, part is brought in with dust and insects. However, on the grain, as on the entire surface of plants, only a few microorganisms, the so-called epiphytes, develop. Epiphytic microorganisms that multiply on the surface of stems, leaves and seeds of plants are called phyllo-sphere microorganisms. Epiphytes feed on the products of plant exosmosis. The living conditions of epiphytic bacteria are peculiar. They are content with small reserves of nutrients on the surface of plants, are resistant to high concentrations of phytoncides, and withstand periodic fluctuations in humidity. Therefore, their number is small and the species composition is fairly constant. More than 90% of epiphytic microorganisms are putrefactive bacteria. Basically, epiphytic microflora is represented by non-spore-bearing bacteria. Most of the bacterial population of grain is made up of non-spore-bearing rods of the genus Pseudomonas, which actively develop on the surface of plants. Pseudomonas herbicola (Erwinia herbicola) is especially common, forming golden-yellow colonies on solid media. There are also Pseudomonas fluorescens, micrococci, lactic acid bacteria, yeast. Bacilli and microscopic fungi make up a small percentage.
Under certain conditions, epiphytic microorganisms can be useful for plants, since they prevent the penetration of parasites into plant tissues.
During grain storage, epiphytic microorganisms can play a negative role. In mature grain, water is in a bound state and is inaccessible to micro-organisms. On such grain, they are in a state of suspended animation (rest). The development of microorganisms on grain, and, consequently, the safety of the latter is decisively influenced by: humidity, temperature, degree of aeration, grain integrity and the state of its integumentary tissues. On grain with high humidity, microorganisms multiply the faster, the higher the temperature.
The development of microbiological processes in stored grain with high humidity leads to a noticeable and sometimes very significant increase in temperature. This phenomenon is called thermogenesis.
Self-heating of grain leads to a change in microflora. The epiphytic microflora characteristic of the grain disappears. First, non-pigmented non-spore-bearing rods multiply abundantly, displacing Erwinia herbicola. Later, heat-resistant (thermotolerant) micrococci appear, forming on dense media most often small white flat colonies, mold fungi, actinnomycetes. Further development of the self-heating process (over 40-50 ° C) promotes the development of spore-forming and thermophilic bacteria.
As self-warming progresses, the species composition of molds also changes. The Penicillium species, which prevailed at the beginning, are being replaced by the Aspergillus species.
Thus, according to the species composition of microflora, one can judge not only whether the grain was subjected to self-heating, but also how far this process has gone. The predominance of Ertioinia herbicola in the microbial coenosis of grain is an indicator of its good qualities. A large number of spore-forming bacteria and fungi indicates a loss of seed germination.
Favorable conditions for the development of microorganisms on the grain lead to the accumulation of toxins secreted by them. As a result, when feeding such grain to livestock and poultry, feed poisoning often occurs.
Thus, proper storage of grain should be limited to preventing the development of microorganisms on it.
To quantitatively account for microorganisms on the grain, a 5 g sample is placed in a flask with 50 ml of sterile tap water and 2-3 g of sand. The flask is shaken with circular rotary movements for 10 minutes. Further dilutions are prepared from the resulting extract (10 ~ 2; 10_3; 10-4). Separate sterile Mohr pipettes take 10 ml of suspension and transfer to flasks containing 90 ml of sterile tap water. Then, from each flask, take 1 ml of a suspension of the corresponding dilution into sterile Petri dishes in duplicate. In each Petri dish, pour 1 tube of melted, but pre-cooled to 50 ° C MPA. The plates are incubated at a temperature of 30 ° C. Along with the MPA, use the elective media described in the section "Analysis of the silage".
After 3-5 days of incubation, the total number of colonies grown on MPA in dishes is counted, and the number of microorganisms per gram of grain is calculated.
To determine the qualitative composition of the microflora of the grain, the colonies are grouped according to cultural characteristics, preparations are made from each group of colonies, the belonging of microorganisms to a genus or family is revealed, and the number of bacteria of each group is determined as a percentage of the total number of microorganisms.
For identification, the isolated cultures of microorganisms are purified.
Based on microbiological analysis, a conclusion is made about the quality of the grain.
Erwinia herbicola predominates (up to 80%) on fresh, benign grain, forming shiny orange colonies. There are Pseudomonas fluorescens, which forms yellowish-greenish fluorescent colonies, non-pigmented non-spore-forming rods, yeast (colonies are shiny, convex, often colored in pink tones). When counted on wort agar with chalk, lactic acid bacteria are detected, forming lenticular small colonies with chalk dissolution zones.
Erwinia herbicola and Pseudomas fluorescens are not detected on stale grain stored in high humidity conditions. Micrococci are found that form small white shiny flat colonies, spore-forming rods, actinomycetes, as well as non-spore-bearing rods. When counted on wort agar, a significant number of fungi, mainly belonging to the genus Penicillium, and also Aspergillus, are revealed.
Materials and equipment. The grain in the flasks is fresh and stale, stored in high humidity conditions. Weights and weights. Watch glasses. Flasks with sterile water (90 ml), flasks with sterile water (50 ml) and sand. Mohr's sterile pipette, 10 ml and 1 ml. Sterile Petri dishes. MPA in test tubes and flasks. Water bath, tripod. Microscopes and everything necessary for microscopic examination.
SILO ANALYSIS
Lactic acid bacteria that live on plants play an important role in forage ensiling. Silage is based on lactic acid fermentation. Lactic acid bacteria ferment the sugars of silaging plants into lactic and partially acetic acid, which suppress the development of putrefactive, butyric and other undesirable bacteria that spoil the feed. Lactic acid bacteria reduce the pH of the feed to 4.2-
If the acidity of the silage for one reason or another decreases (the pH becomes higher than 4.5-4.7), then conditions are created that are favorable for the life of microorganisms harmful to the preservation of KLPM.
It accumulates foul-smelling butyric acid, amines, ammonia and other products.
In order to ensure the normal development of lactic acid bacteria in the process of ensiling, it is necessary to have a sufficient sugar content in the silage plants and to isolate the feed from the air, that is, to create anaerobic conditions.
Mold fungi tolerate strong acidification, but they are strict aerobes, so they cannot reproduce in a well-compressed, covered, fermented food.
If you follow the breakdown of sugar and the formation of organic acids during ensiling, you will notice that with a decrease in sugar, the amount of organic acids increases. However, a decrease in pH depends not only on the amount of lactic and acetic acids, but also on the buffering capacity of plant material, which, in turn, depends on protein and salts. The more the plant mass is buffering, the more acids are needed to lower the pH of the feed, i.e. the more the buffer material binds and neutralizes part of the lactic acid (hydrogen ions). Therefore, despite the accumulation of acid, the pH of the medium almost does not decrease until all the material that provides buffering is consumed. The acids bound by the buffer material form a reserve of so-called bound acids in the silage. A more buffered feedstock for good quality silage should have more sugars than a less buffered feedstock. Thus, the silage capacity of plants is also determined by specific buffering properties.
The buffer capacity of the plant mass is determined by titration of the ground plant mass with a 0.1 N solution of lactic acid to pH 4.0. It is determined how much lactic acid is required to shift the pH to 4.0. Since about 60% is consumed for the formation of lactic acid of feed sugars, then, having calculated 100%, the so-called sugar minimum for a given plant raw material is determined, i.e. the smallest amount of sugar required for the formation of such an amount of lactic and acetic acids to shift the pH to 4.0.
Plants are good for silage if they have a lot of sugar and a low sugar minimum. If the actual
If the sugar content in plants is approximately equal to the minimum sugar content, then they are poorly ensiled and the slightest deviation during the ensiling process will lead to spoilage of the silage. If the actual sugar content is less than the sugar minimum, then such plants are not ensiled.
During ensiling, flowers and leaves are preserved, which contain the greatest amount of nutrients. Loss of dry matter with proper silage does not exceed 10-15%. Good silage is characterized by the following characteristics: color - olive green
(only slightly changes), the smell is pleasant (soaked apples, baked bread), pH 4-4.2, total acidity 2-2.5% (in terms of lactic acid), humidity 70%. The microflora of good silage is represented by lactic acid sticks and lactic acid streptococci; yeast is often found in small quantities. The latter form esters that give the silage a pleasant smell and enrich the feed with protein and vitamins. However, in large quantities, yeast degrades the quality of the silage - it reduces its acidity, as it competes with lactic acid bacteria in sugar consumption.
In the first period after laying the silage, the microflora of the mixed phase of fermentation develops rapidly, usually present on the surface of healthy plants: putrefactive bacteria (mainly non-spore-forming rods), bacteria of the E. coli group, butyric acid bacteria, etc. acid-fast lactic acid sticks. After two weeks (with a decrease in pH to 4.0 and below), the microbiological processes in the silage generally end.
For analysis, an average sample of the silage is taken from the end of the trench, pits or ground heaps. To do this, removing the top layer with a sterile knife, cut out the cubes along the middle line of the shoulder, with an interval of 1 m. They are placed in a sterile glass jar with a capacity of 1-2 liters with a ground stopper so that the silo is packed tightly and to the top. The samples are mixed in a sterile crystallizer, crushed with sterile scissors and weighed for analyzes.
The study is recommended to be carried out no later than 24 hours after sampling.
Microscopic examination of the microflora of the silage
To get acquainted with the microflora of silage, a preparation is prepared from it as follows. Take the silage with tweezers and press it tightly against the slide without adding water, trying to leave an imprint on the slide. The preparation is dried in air, fixed on a flame and stained with methylene blue (2-3 min). After washing off the dye with tap water and drying away from flame, microscopy with an immersion system.
The specimen reveals thin non-spore-forming rods varying in size (lactic acid bacteria) and lactic acid streptococci. They are usually dominated by Lactobacterium plantarum - homoenzymatic mesophilic "short rods, often arranged in parallel rows. Sometimes budding yeast cells are found. Spore-forming bacteria are rarely observed. In poor silage, spore-forming rods (butyric acid bacteria, aerobic putrefactive bacteria) are detected. mushrooms.
Quantification of microorganisms in the silo
A 5 g sample of silage is placed in a flask with 50 ml of sterile tap water and 2-3 g of sand. The flask is shaken with circular rotary movements for 10 minutes. From the resulting extract prepare subsequent dilutions (10-2; 10+ 10+ 10+ 10 ~ 6), and then sow from the corresponding dilutions on elective media, 1 ml of suspension at deep sowing, 0.05 ml of suspension at surface sowing. Crops are kept at a temperature of 28 ° C.
Determination of the number of lactic acid bacteria is carried out on wort agar with chalk or cabbage agar with chalk (medium 1, 1a), as well as on cabbage agar with alcohol and chalk (medium 2) - deep sowing. Chalk dissolution zones are formed around the lactic acid bacteria colonies due to the accumulation of lactic acid (Fig. 37).
Counting of lactic acid bacteria colonies on wort agar with chalk and cabbage agar with chalk is carried out on
6th day, and on cabbage "agar with alcohol and chalk, on the 7-10th day. Wednesday 2 is necessary to identify lactic acid bacteria in the epiphytic microflora of the original plant mass, since alcohol inhibits the growth of extraneous microflora. Amount of extraneous microflora ( aerobic putrefactive microorganisms) is determined by deep inoculation on peptone agar (medium 3). Colonies are counted at 5

Rice. 37. Chalk dissolution zones around the silage lactic acid bacteria colonies.
7th day.
The number of microscopic fungi and yeast is determined on wort agar with streptomycin (medium 4) by surface inoculation. Colonies are counted on the 3-4th day (if necessary, again on the 7-8th day).
The titer of butyric acid bacteria is set on Emtsev's liquid medium (medium 5a) and potato medium (medium 5). To determine the number of spores of meat-acid bacteria, inoculation is carried out from the suspension, after pasteurization for 10 minutes at 75 ° C. The results of the analysis are taken into account by the intensity of gas evolution (pieces of potatoes float to the surface of the liquid), and the titer of butyric bacteria and their spores is established by the method of limiting dilutions according to McCready.
Aerobic proteolytic bacteria are counted in meat-peptone broth (medium 6) according to the accumulation of gas in the floats. Crops are kept at 28 ° C for two weeks.
When analyzing silos from grasses grown on the background of high doses of nitrogen fertilizers, denitrifying bacteria are also counted on Giltai's medium (medium 7). Crops are kept for 10-12 days at 28 ° C. The denitrifiers are counted according to the intensity of gas evolution and the change in the color of the indicator.
When analyzing the silage, the spores of aerobic putrefactive bacilli are also recorded. On dense media (Wednesday 8)
do surface sowing. The dishes are incubated at 28 ° C, the colony count is carried out on the 4th day.
Bacteria of the Escherichia coli group are taken into account on Kessler's or Bulir's medium by the release of gas and its accumulation in the floats. The tubes are kept for 48 h at 40-42 ° C.
Composition of elective media
Wednesday 1. Wort agar with chalk. Wort, diluted to 3% according to Ealling, - 1 l, agar - 20-25 g, sterile chalk - 30 g. Sterilized at 0.5 ATM for 30 minutes.
Wednesday 1a. Cabbage agar with chalk. Cabbage broth - 900 ml, yeast extract - 100 ml, peptone - 10 g, glucose - 20 g, sodium acetate - 3.35 g, manganese sulfate - 0.025 g, agar - 15-20 g.
Sterile chalk is added to the flasks at the rate of 5 g per 200 ml of medium. Sterilized at 0.5 ATM for 30 minutes.
Wednesday 2. Cabbage agar with alcohol and chalk. Add 20 ml of ethanol (96%) per 200 ml of medium to the melted medium cooled to 50 ° C, shake thoroughly and pour into Petri dishes with inoculum.
Wednesday 3. Peptone agar. ... Peptone - 5 g, K2HPO4 - 1 g,. KH2PO4 - 0.5 g, MgSOi - 0.5 g, NaCl - traces, tap water - 1 l, agar, well washed, - 15-20 g. Sterilized at 1 atm for 20 minutes.
Wednesday 4. Wort agar with streptomycin. Wort, diluted to 3% according to Balling, - 1 l, agar - 25 g. Sterilized at 0.5 ATM for 30 minutes. Before pouring the medium into Petri dishes, add 80-100 units to the wort-agao. streptomycin for every milliliter of medium.
Wednesday 4a. Acidified wort agar. Wort, diluted to 3% according to Balling, - 1 l, agar - 20-25 g. Sterilized at 0.5 ATM for 30 minutes. Before pouring the medium into Petri dishes, 2 ml of lactic acid (per 1 liter of medium), boiled for 10 minutes in a water bath, are added to the molten wort-agar.
Wednesday 5. Potato medium with chalk. Sterile chalk is added to the test tubes (at the tip of a scalpel), 8-10 potato cubes 2-3 mm in size are poured with tap water to s / 4 of the test tube volume. Sterilized at 1 ATM for 30 minutes.
Wednesday 5a. Potato starch - 20 g, peptone - 5 g, yeast autolysate - 0.2 mg / l, KH2P04 - 0.5 g, K2HPO4 - 0.5 g, MgSC> 4 - 0.5 g, NaCl - 0.5 g , FeS04- 0.01 g, MnS04- 0; 01 g, CaCO3- 10 g, a mixture of trace elements no M.V. Fedorov-1 ml, distilled water - 1 l, tnoglycolic acid - 0.05%, neutralroth - 0.004 %) pH 7.4-7.5. Sterilization of the medium is carried out at 0.5 atm for 30 minutes. The incubation temperature of crops is 30-35 ° С.
Wednesday 6. Meat-peptone broth. Peptone - 10 g, NaCl - 4 g, broth - 1 liter. Pour into test tubes with floats up to 3 / "volume. Sterilized at 1 ATM for 20 minutes.
Wednesday 7. Wednesday Giltai (modified). Sodium citrate-2 g, KNO3- 1 g, KH2P04- 1 g, K2HP04- 1 g, MgS04 -
1 g, CaCl2 - 0.2 g, FeCl3- traces, distilled water - 1 l,
1% bromothymol blue solution (pH 6.8-7.0). Sterilize prn 1 ATM for 20 minutes.
Wednesday 8. Meat-peptone agar and wort-agar 1: 1. Sterilized at. 0.5 atm for 30 minutes.
Wednesday 9. Wednesday Kessler. To 1 liter of tap water add 50 ml of fresh bovine bile and 10 g of peptone. The mixture is boiled for 15 minutes in a water bath, shaken. When the peptoi dissolves, filter through cotton wool, then add 10 g of lactose. After dissolving lactose, a slightly alkaline reaction is established (pH 7.6) and 4 ml of 1% aqueous solution gentian violet at the rate of 1 g of dry paint per 25 liters of medium. The liquid is poured into test tubes with floats and sterilized at 1 atm for 15 minutes.
Wednesday 10. Wednesday Bulir. Kіl of meat-peptone broth add 12.5 g of mannitol and 6 ml of 1% solution of neutralroth. The medium is poured into test tubes with floats and sterilized at 0.5 atm for 30 minutes. The medium has a cherry color, with the development of E. coli it turns orange and gas accumulates in the float.
Colonies dominating on solid media are microscoped. To detect butyric acid bacteria from test tubes with potatoes, prepare a preparation in a crushed drop with the addition of Lugol's solution.
Determination of acidity
Determination of total acidity in silage. A 20 g sample of silage is taken and placed in a 500 ml conical flask with a reflux condenser. The contents of the flask are poured over 200 ml of distilled water, mixed thoroughly and heated for 1 hour. After cooling, the contents of the flask are filtered through a paper filter and 10 ml of the filtrate (with double the amount of distilled water) is titrated with 0.1 N HCl. sodium hydroxide solution in the presence of phenolphthalein until a stable slightly pink color appears.
The total acid content in silage in terms of lactic acid is expressed as a percentage. 1 ml 0.1 N. NaOH solution corresponds to 0.009 g of lactic acid. Multiplying the amount of 0.1 N. NaOH consumed for titration of the extract from 100 g of silage by 0.009, find the amount of acid in the silage (%).
Calculation example. For titration of 10 ml of the extract, 1.7 ml of 0.1 N. NaOH, therefore, 34 ml of 0.1 N will go for 200 ml. NaOH.
200 ml of extract is obtained from 20 g of silage, and X ml of 0.1 N will be consumed to neutralize 100 g of silage. NaOH:
100.34
X = --¦ = 170 ml 0.1 i. NaOH.
Multiplying 170 by 0.009 gives the percentage of lactic acid:
170 X0.009 = 1.53%
Sufficiently accurate results are obtained even if the acidity is determined as follows. A 5 g sample of silage is taken, ground in a mortar and placed in a wide test tube (2-
cm). The contents are poured into 50 ml of distilled water, closed with a rubber stopper and mixed thoroughly. The weighed amount of silage is insisted at 10-12 ° C for 30 minutes, and then the acidity of the extract is determined by titration. 10 ml of the extract (with double the amount of distilled water) is titrated with 0.1 and. sodium hydroxide solution in the presence of phenolphthalein until a stable slightly pink color appears.
Calculation example. For titration of 10 ml of the extract, 1.7 ml of 0.1 N. NaOH, therefore, for 50 ml of extract-
ml; 50 ml of extract is obtained from 5 g of silage, and X ml of 0.1 N will be consumed to neutralize 100 g of silage. NaOH:
100.8,5
X = L = 170 ml 0.1 N. NaOH;
5
170 X0.009 = 1.53% lactic acid.
Determination of pH in silage. Preparation of the extract of the silage for determining the pH in it is carried out in the same way as for determining the total acidity in the silage. pH is found using indicators or electrometric determination. When using indicators, proceed as follows. Take 2 ml of the silage extract into a porcelain cup and add 2 drops of the indicator (a mixture of equal volumes of bromothymol blue and methylroth). The concentration of hydrogen ions is determined by comparing the color of the contents of the dish with the data below. PH indicator color Red 4.2 and below Red-orange 4.2-4.6 Orange 4.6-5.2 Yellow 5.2-6.1 Yellow-green 6.1-6.4 Green 6.4- 7.2 Green-blue 7.2-7.6 Materials and equipment. Weights and weights, 500 ml conical flasks with a reflux condenser, wide test tubes, tripod with asbestos grids, 100 ml and 250 ml flasks, funnels, paper filters, 10 ml and 2 ml pipettes, porcelain cups, tweezers; indicators: a mixture of equal volumes of bromothymolblow and methylroth, phenolphthalein, methylene blue, Lugol's solution (1: 2).
Culture media, sterile Petri dishes, sterile 1 ml pipettes, sterile tap water in 9 ml tubes and in 50 ml flasks. Plates and test tubes with cultures. Microscope and everything needed for microscopy.
YEAST FEED
Yeast contains a lot of easily digestible protein, rich in ergosterol, easily converted to vitamin D, vitamins A, B, E; they reproduce vigorously, are unpretentious to their habitat, they can be easily grown on agricultural and industrial waste. Fodder yeast is currently prepared in large quantities by propagating it on industrial waste, including plant hydrolysates (straw, wood waste, etc.). Yeast (Candida) has now been found that multiplies well on hydrocarbons. This makes it possible to prepare cheap feed yeast using oil industry waste. In addition to adding dry yeast to the feed ration, feed yeast is used. To do this, a yeast culture is introduced into the crushed and moistened plant mass. Stir periodically. Yeast multiplies abundantly in the feed, which usually coincides with acidification. However, the accumulation of acids is explained by the development of lactic acid bacteria, which always live on plant matter. For active reproduction of yeast in feed, a number of conditions are required: a well-prepared nutrient medium (crushing, humidity, temperature 25-27 ° C, sufficient aeration, pH 3.8-4.2). You can only yeast feed rich in mono- and disaccharides. Otherwise, yeast and lactic acid bacteria will not develop. In addition to concentrates, succulent feed is subjected to yeast, to which roughage is mixed.
When concentrated feed is fermented, 5-6% of dry matter is lost. These losses fall mainly on carbohydrates fermented by yeast.
When yeast feed, it is of interest to enrich the feed with protein due to the introduced mineral nitrogen. Yeast, consuming ammonium salts, enriches the substrate with protein by 13-17% (calculated on dry matter). Yeast makes the feed pleasantly acidic, enriches it with vitamins, stimulates appetite in animals, eliminates many diseases (paratyphoid infections, rickets of young animals, skin lesions and other diseases), favorably affects milk production in cows, poultry egg production, and an increase in animal weight gain. |
In laboratory practice, feed yeast can be * carried out on beets, which are pre-cut into small pieces, or on bran. The food is introduced into a tared 100 ml beaker with a glass rod, moistened in the case of bran to the consistency of thick sour cream. The glasses of food are weighed. The mass of the moistened feed should be about 100 g. A one-day dilution of baker's yeast on wort in an amount of 5% is used as a starter (5 ml of yeast suspension is added per 100 g of feed).
The food is thoroughly mixed with a glass rod, the glass is covered with a paper label on which the container of the glass and the mass of the moistened food are recorded "(without leaven).
Leave the yeast food at room temperature, stirring the contents of the glass several times a day.
After 1-2 days, the number of yeast cells in the feed is determined.
Yeast cells counting in yeast suspension (starter culture)
"by the method of direct counting under a microscope
Take a loop of a certain amount of yeast culture (1 loop captures 0.01 ml), put it on a glass slide, add the same amount of milk and spread over a certain area (4 cm2). The preparation is air-dried, carefully fixed on a flame, and stained with methylene blue for 10 min.
Under a microscope with an immersion system, the number of yeast cells is counted (in 10 FIELDS
vision). The number of yeast cells in 1 ml of starter culture is determined by the formula:
S
-A. one hundred,
Si
where A is the average number of yeast cells in one field of view;
S- square area (4 s.m2);
Si is the area of the field of view,
Si = jrr2,
where r is the radius of the objective, determined using an object micrometer. A drop of cedar oil is applied to the object micrometer and the radius of the objective is determined on the line of the object micrometer with the immersion system.
If the lens g is "0.08 mm, then
S, = 3.14.0.0064 = 0.02 mm2,
S 400 mm2
=20000.
Si 0.02 mm2
Consideration of yeast cells in chewed feed
After 1-2 days, glasses of yeast food are weighed. Due to the fermentation of sugar and evaporation of water, the weight of the feed is reduced. Take an average sample in the amount of 10 g, add to a flask containing 100 ml of sterile tap water, and shake for 5 minutes. Then on a certain area of the glass slide (4 cm2) smear a certain volume of suspension (0.01 "ml-1 loop) and add 0.01 ml of milk. The drug is dried in air, fixed carefully on a flame, stained with methylene blue for 10 minutes. Count the number of yeast cells in one field of view (10 fields of view).
The average number of cells in one field of view is multiplied by 20,000, by 100 and 10, and the number of cells in 1 g of feed is obtained. This figure is then multiplied by the weight of the feed and the amount of yeast in the entire feed is determined.
To find out how many times the amount of yeast increased during the yeast yeast process, you need to divide their number by the initial number of yeast cells contained in the starter culture. Food is considered good if no more than 10 foreign bacterial cells (not yeast) are found in one field of view.
Materials and equipment. Scales and weights, 100 ml glasses with glass rods, beets, bran, yeast suspension, 5-10 ml graduated pipettes, loops, milk in test tubes, 4 cm2 slides made of graph paper, object micrometer, methylene blue indicator, glasses with yeast food. Microscope and everything needed for microscopy.

Epiphytic microflora of plants. The root and root systems of plants are seeded with a large number of different microflora. In the root zone (rhizosphere) there is a large number of dying off root residues, which are a nutrient substrate for saprophytic soil microflora. These bacteria are putrefactive, like some representatives of the intestinal group found in the root zone of plants. In addition to them, the rhizosphere contains a significant amount of heterofermentative lactic acid bacteria. The number of spore-forming becomes significant only after the death of the root system. Of the molds, Penicillium and Fusarium predominate.

Some bacteria and microscopic fungi that live at the root gradually move to the terrestrial part of the growing plant and settle on it. On the surface of plants, only a certain group of microorganisms is able to exist, which is called epiphytic. On the surface of plants, there are ammonifiers, butyric acid bacteria, lactic acid bacteria, bacteria of the E. coli group (BGKP) and representatives of other physiological groups of microorganisms. Unlike other microbes, epiphytes tolerate well the action of phytoncides, solar radiation and feed on substances secreted by plants. Being on the surface of plants, epiphytes do not damage or penetrate into the tissues of a healthy plant. A large role in this process belongs to natural immunity and bactericidal substances that plants secrete. All plants secrete phytoncides that affect the physiological processes of microbes.

The relationship between microbes and cuttings. After mowing the plants, the permeability of the cells is disturbed, bactericidal substances are destroyed, which prevented the penetration of microbes into their tissues. All microorganisms located on the surface of plants are activated: putrefactive, butyric, lactic acid bacteria and mold fungi, etc. Microorganisms, and primarily fungi, with their intensive development, reduce the quality of feed and its nutritional value. Under the influence of Aspergillus, Penicillium, fats are changed, then carbohydrates and proteins, various decay products accumulate in the feed, dramatically changing the smell and taste of the feed, including organic fatty acids, ammonia and peptones. These processes are especially active at high humidity and temperature.

Anaerobic bacteria develop in the deep layers of the food, and aerobic bacteria and molds grow on the surface. As a result of their vital activity, the decomposition of the constituent parts of the feed occurs, which leads to the loss of nutrients and spoilage of the feed. It acquires a putrid odor, the fibers break easily, their consistency becomes smeared. Such food is poorly eaten by animals and can cause food poisoning.

Sen about. Drying is the oldest and most widespread method of preserving green mass and other forage (grain, straw). The essence of this process is that during drying, microbiological processes in the feed are suspended due to the removal of "free" water from it, which makes up most of the moisture present in the feed. So, if fresh grass contains 70-80% moisture, then hay contains only 12-16%. The water remaining in the feed is "bound" water and cannot support the development of microorganisms. Thus, the task of drying is to remove excess water from the feed with the least loss of organic matter. During drying, the number of vital microorganisms on the surface of the feed gradually decreases, but, nevertheless, you can always find in them a greater or lesser number of epiphytic and saprophytic microflora that has come from the air and soil. The reproduction of saprophytic microflora as a result of an increase in humidity leads to a noticeable increase in temperature. This increase in temperature associated with the vital activity of microorganisms is called thermogenesis.

Making ordinary hay. Hay is made from cut grass, which has a moisture content of 70-80% and contains a large amount of free water. Such water creates favorable conditions for the reproduction of epiphytic microflora, which causes rotting of the grass. Drying the grass to a moisture content of 12-17% stops microbiological processes, which stops the destruction of dried plants.

After drying, a large amount of epiphytic microflora remains in the hay, but since there are no conditions for their reproduction, they are in anabiotic state. When water gets on the dried hay, the activity of microorganisms begins to intensify, which leads to an increase in temperature to 40-50 0 С and above. With self-heating of the plant mass, a pronounced change in microflora occurs. First, mesophilic bacteria multiply in the warming mass. With an increase in temperature, they are replaced by thermophiles, capable of developing at temperatures up to 75-80 0 C. The charring of the plant mass begins at a temperature of about 90 0 C, at this temperature microorganisms cease their activity, further processes proceed chemically. Combustible gases are formed - methane and hydrogen, which are adsorbed on the porous surface of charred plants, as a result of which spontaneous combustion can occur. Ignition occurs only in the presence of air and insufficiently compacted plant matter.

Microorganisms do not use all the energy of the nutrients they consume; excess energy is released into the environment mainly in the form of heat. The higher the temperature of the warming food, the lower its quality. But the phenomenon of thermogenesis is not always harmful. In the northern regions, where there is little heat and high humidity, it is used to make brown hay.

Making brown hay common in those areas where the climatic conditions make it difficult to dry hay. To dry the feed, not solar energy is used, but the heat released as a result of the vital activity of microorganisms developing in the plant mass. The mown and well-dried grass is put into small heaps, then into haystacks and stacks. Since the plant mass still contains free water, microorganisms begin to multiply, heat is released, which dries up the plants. After a month, with the extinction of microbiological processes, the plant mass is cooled, which can be stored long time... Hay prepared in this way loses its natural color, becomes brown, but is willingly eaten by animals.

Haylage - This is a type of canned food obtained from wilted grasses, mainly legumes, harvested at the beginning of budding.

Scientific research carried out in recent years has shown that a particularly promising way of preserving various herbs, and primarily clover and alfalfa, is the preparation of so-called haylage from them.

The silage preparation technology includes mowing, crimping and placing the wilted grass in the storage. It is possible to obtain good-quality haylage and reduce its losses during storage to a minimum only when fodder is stored in capital storages - towers and trenches. Compared to towers, trenches are simpler and easier to operate. For the preparation of high-quality haylage, finely chopped plants (particle size 2-3 cm) are placed in storage, which ensures flowability and compaction of the forage, the masses are carefully compacted and, which is very important, the preparation of haylage should be carried out in 2-4 days, i.e. in a short time. Insufficient compaction and long laying times cause an undesirable increase in temperature, which impairs the digestibility and loss of organic matter in the feed. After loading the storage, the silage is covered with a layer of freshly cut grass, then with plastic wrap and on top with a layer of earth and peat.

The safety and quality of the silage depends on the degree of sealing of the storage. with access to air, putrefactive processes begin, leading to spoilage of the feed.

Unlike conventional silage, the preservation of which is due to the accumulation of organic acids up to pH 4.2-4.4, the conservation of haylage is achieved due to the physiological dryness of the feedstock, preserved under anaerobic conditions. If the moisture content of the canned mass is in the range of 40-50%, then it ferments well and, even with a deficiency of carbohydrates, gives high quality food. At the same time, the pH of the feed can be quite high - about 5.0. This is due to the fact that putrefactive bacteria have a lower osmotic pressure than lactic acid bacteria. When the feed is dried, putrefactive processes are stopped in it, but the causative agents of lactic acid fermentation continue to act. This is the basis for the preparation of haylage, when a somewhat dried mass is laid in a special trench, as in cold ensiling.

In terms of its properties, silage is closer to green mass than conventional silage. This is a fresh feed, its acidity corresponds to a pH value of 4.8-5.0, sugar is almost completely retained in it, while in silage it is converted into organic acids.

At the specified moisture content of plants, only mold can develop intensively. Molds are strict aerobes, therefore, an indispensable condition for making haylage is to reliably isolate it from the air. The air remaining in the canned mass is quickly used for respiration by the still living plant cells, and all the free space between the particles of the crushed feed is filled with carbon dioxide.

Thus, for the preparation of good-quality haylage, two conditions must be met:

1) reduce humidity plant mass up to 45-55%;

2) create strict anaerobic conditions to prevent the development of putrefactive bacteria and molds.

However, the technology of making silage is based not only on physical, but also on microbiological processes, which are slower than in silage. In silage, the maximum number of microorganisms accumulates by the 7th day, and in haylage their number reaches its maximum only on the 15th day, i.e. lactic acid fermentation in haylage is much weaker than during ensiling and depends on the moisture content and the type of canned raw materials. Therefore, the pH in haylage is higher than in silage and ranges from 4.4 to 5.6. According to A.A. Zubrilin et al. (1967), the number of lactic acid microbes in haylage is 4-5 times less than in silage ... As a result, haylage contains more unused sugar than silage.. So, if in silage all the sugar is converted into organic acids, then about 80% of the sugar is retained in the haylage. As a result of creating unfavorable conditions for the development of microflora in canned fodder, eliminating juice leakage and mechanical loss of leaves and inflorescences during harvesting and storing haylage, the total loss of nutrients in haylage does not exceed 13-17%. In this way , silage combines the positive qualities of hay and silage.

Unlike silage, silage, having low moisture content, does not freeze, which simplifies its unloading and feeding to animals. Hay can be harvested from all herbs, because Unlike silage, it does not matter how much easily digestible carbohydrates are in the grass, and to which silage group these plants belong.

Microbiology of forage ensiling. The term "silo" (silos) is of very ancient origin, in Spanish it means "pit" for storing grain (now, has lost its original meaning). Such granaries were common in many areas of the Mediterranean coast. As early as 700 BC, the landowners of Greece, Turkey, North Africa widely used such pits for storing grain. Over time, this principle was used for storing and preserving green mass.

Silage - complex microbiological and biochemical process of preserving succulent plant mass.

The essence of ensiling is that as a result of the fermentation of vegetable carbohydrates by enzymes of lactic acid bacteria, in the silage mass accumulates lactic acid, which has antimicrobial properties, as a result of which the feed does not rot and becomes stable during storage.

To obtain silage of good quality and with the least loss, certain conditions must be observed.

1. Use forage for silage containing a sufficient amount of easily silted carbohydrates(corn, sunflowers, peas, green oats, meadow grains) or add them to non-silted plants.

2. It is necessary to well isolate the silage material from the air to create anaerobic conditions, under which unfavorable conditions are created for the reproduction of putrefactive and mold microorganisms

3. The forage for silage must have optimal humidity- 65-75%, at which there is an intensive formation of organic acids. At low humidity, the silage mass is poorly compacted, there is a lot of air in it and conditions are created for self-heating, the development of mold and putrefactive bacteria.

4. The silage must have optimal temperature for the development of lactic acid bacteria 25-30 0, at this temperature there is a normal process of fermentation of feed with little loss of nutrients. Finished silage is moderately sour, yellow-green in color, with a pleasant specific smell.

Biochemistry of microbiological processes during ensiling.

Lactic acid bacteria are a large and diverse group that includes both coccoid and rod-shaped forms.

Lactic acid bacteria are divided into two main groups according to the quality of the end products of fermentation:

Homofermentative e, which form mainly lactic acid from the carbohydrates they ferment and only traces of various by-products. Typical representatives of this group are lactic acid streptococci and lactic acid sticks. With this fermentation, a product with a pleasant sour taste and smell is obtained.

Heterofermentative, forming, in addition to lactic acid, a significant amount of by-products (ethyl alcohol, acetic acid, carbon dioxide). Among them there are coccal and rod-shaped forms.

For the development of all lactic acid bacteria, the plant mass must contain easily digestible carbohydrates. The ability to produce lactic acid varies in the same type of microorganism due to many factors, including the quality of the nutrient substrate. So, when hexoses are fermented, they form lactic acid as the main product, which is obtained as a result of the splitting of one sugar molecule into two molecules of lactic acid according to the following equation:

C 6 H 12 O 6 = 2C 3 H 6 O 3

During the fermentation of pentoses, the end products of fermentation will always contain more acetic acid than during fermentation, for example, hexose - glucose or fructose. And since pentosans are part of the plant mass, the presence of acetic acid in the finished silage is also the result of the vital activity of lactic acid, not acetic acid bacteria. Therefore, even in good silage, there is always a certain amount of acetic acid. (Danilenko I.A. et al., 1972). And, if the composition of organic acids is at least 65-70% lactic, and acetic acid 30-35%, then fermentation was proceeding correctly. There are two known methods of ensiling: cold and hot.

Cold way ensiling is characterized by the fact that the maturation of the silage occurs at a temperature of 25-30 0 C. With such ensiling, the crushed plant mass is tightly placed in a trench, and from above it is isolated from the air to create anaerobic conditions in which the development of putrefactive bacteria and molds is suppressed. An indispensable condition for obtaining high-quality forage is fast isolation of the silage mass from the air, therefore, the duration of filling the trench with chopped green mass should not exceed 3-4 days. To prevent self-heating (thermogenesis), it is necessary to lay the crushed green mass quickly and continuously, with constant compaction.

Hot method For silage, the green mass is laid loosely, in a layer of 1.0-1.5 m for 1-2 days, then a second layer of the same thickness as the first is laid. When oxygen is available in the plant mass, vigorous microbiological processes develop, as a result of which the feed temperature rises to 45-50 0 C. The lower layer of plants, softened by high temperature, is compressed under the weight of a new layer of feed. This causes the removal of air from the lower layer, so aerobic processes stop, and the temperature begins to decrease. The last top layer is tamped and covered tightly to protect it from the air. Overheated silage has a brown color, the smell of apples or rye bread, and is well eaten by animals. However, the feed value of hot silage is significantly lower than that of cold silage.

The ensiling process can be roughly divided into three phases.

First phase silage is called mixed microflora phase... In the plant mass, the rapid development of epiphytic microflora (putrefactive, lactic acid, butyric acid, microscopic fungi, yeast), introduced with food, begins. The duration of the first phase depends on the quality of the feed, the density of laying, the ambient temperature, but more often it is short-lived.

In the second phase – main fermentation phase- the main role is played by lactic acid bacteria, which produce lactic acid. With an optimal sugar content in the plant mass, intensive lactic acid fermentation leads to the formation of a significant amount of organic acids (mainly lactic acid), which is necessary to acidify the feed to a pH of 4.2-4.4. At the beginning of this phase, cocci multiply, then, as the acidity increases, they are replaced by acid-resistant lactic acid sticks. Lactic acid has antimicrobial properties, so most putrefactive bacteria die, but spore-forming forms in the form of spores can persist for a long time in silage.

Third phase- final - associated with gradual withering away pathogens of lactic acid fermentation in maturing silage. Lactic acid, when accumulated in high concentration, becomes harmful for lactic acid sticks, which, along with the remaining cocci, begin to die off. Thus, the number of bacteria in the feed is reduced and the ensiling process comes to a natural end.

The composition of the epiphytic microflora of plant raw materials includes various microorganisms (microscopic fungi, butyric bacteria, E. coli), which, if the technological process is disturbed, can activate and cause undesirable processes.

Mold fungi tolerate acidic environment well (pH up to 1.2) and actively reproduce in silo with poor isolation from air. For their life, they use carbohydrates, and if they are lacking, they use lactic and acetic acids. At the same time, the quality of silage deteriorates significantly and the toxic effect of moldy feed on the animal's body is noted. Good sealing of the silos and the creation of favorable conditions for the development of lactic acid fermentation are reliable measures to prevent the development of mold fungi in the silo.

Escherichia coli bacteria are heteroenzymatic microorganisms that, in addition to saccharolytic, also secrete proteolytic enzymes that break down plant proteins to ammonia, thus reducing the value of the forage being ensiled.

Undesirable for the ensiling process and butyric acid bacteria, which are strict anaerobes. In the process of their vital activity, they use sugar, lactic acid, and some amino acids. This is accompanied by putrefactive decomposition of protein, the accumulation of butyric acid and other by-products harmful to the body of animals. The presence of butyric acid is an indicator of putrefactive decomposition of protein with a weak build-up of lactic acid in the silage. Lowering the pH of the medium to 4.2 prevents the development of butyric acid fermentation during ensiling of forage.

Yeast feed. This is a microbiological method of preparing feed for feeding. V chemical composition yeast contains 48-52% proteins, 13-16% carbohydrates, 2-3% fats, 22-40% nitrogen-free extractives and 6-10% ash. Yeast contains many essential amino acids: arginine, histidine, lysine, leucine, tyrosine, threonine, phenylalanine, methionine, valine, tryptophan, which are scarce in plant foods. Yeast contains many B vitamins, vitamin D 2 provitamin, as well as vitamins E, C, etc. And, unlike other protein sources, they have a high reproduction rate and are undemanding to the quality of nutrient sources. The use of yeast is not accidental, for example, 500 kg of yeast gives 80 kg of protein per day, and in a bull of the same weight, the daily gain is at best 500-800 g of protein.

When yeast feed, it is necessary to create favorable conditions for the reproduction of yeast cells: the presence of easily fermented carbohydrates containing mono- or disaccharides, sufficient aeration (otherwise the yeast will switch to anaerobic respiration, the end product of which is ethyl alcohol), a favorable temperature of 25-30 0 С and pH in the range of 3.8-4.2. For yeast, feed mixtures prepared from grain waste, root crops, bagasse, to which roughage are mixed, are well suited, i.e. mixtures rich in carbohydrates and poor in protein (exclude feed of animal origin, on which putrefactive, butyric and other undesirable microorganisms develop).

For the yeast feed, it is necessary to select a dry and bright room to prevent contamination of the yeast feed with mold spores, which may include mycotoxicosis pathogens.

There are three ways to yeast feed: unpaired, sponge and sourdough.

Safe way characterized by the fact that 1% of the diluted yeast is applied immediately to the entire mass of the feed. The mixture is stirred every 30 minutes for 8-10 hours, then the feed is ready for feeding.

With the sponge method, first prepare the dough, which is then added to the yeast feed. To do this, yeast (1% by weight of the feed) is diluted and mixed with one fifth of the feed, kept for 6 hours with stirring. Then the rest of the feed is added to the dough, double the amount of water and the yeast process continues for another 3 hours with constant stirring for air access.

Starter method used when there is an insufficient amount of yeast, therefore, the sourdough is first prepared. For this 0.5 kg of compressed yeast multiply in a small amount of well yeastable carbohydrate feed (grain waste) at 30-35 0 С, after 5 hours they can be used as a ferment. The prepared portion of feed is malted by pouring boiling water over them, - malting occurs within 5 hours at a temperature not lower than 60 0 C. The same amount of water is added to the malted feed and half of the leaven, mix and leave for 6 hours in a warm place, after which the food is ready for feeding. The second part of the remaining leaven can be used 5-10 times to yeast new batches of feed, after which it loses activity.

Yeast feed improves the quality of feed and enriches the feed with vitamins, and the presence of lactic acid increases the appetite of animals.

Foreword (9). Microflora of food products during cold storage

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Microflora of feed

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