Aim. Comprehensive analysis of the morphofunctional state of somatic (cumulus) and germ cells (oocytes) of Sus scrofa domesticus subjected to intraovarian vitrification using silicon dimethylglycerolate (SDMG) are presented.

Materials and methods. Fragments of porcine ovaries (FsPO) 15×20 mm in size were gradually kept in cryoprotective agents (CPA) prepared in phosphate-buffered saline (PBS) with 20% fetal bovine serum (FBS): 25 min. in CPA-1 [7.5 % EG (ethylene glycol) with 7.5 % DMSO (dimethyl sulfoxide)] and 15 min. in CPA-2 (15 % EG with 15 % DMSO and 0.5 M sucrose). The composition of the CPA-2 in experimental groups was modified by addition of SDMG (at concentrations of 2 %, 6 %, or 10 %). FsPO were stored in liquid nitrogen. FsPO were devitrified by exposure 1 minute in solution 1 (80 % PBS, 20 % FBS, 0.5 mol/l sucrose) and 5 minutes in solution 2 (80 % PBS, 0.25 mol/l sucrose). The following indicators of cryoresistance of devitrified cumulus-oocyte complexes (COCs) were analyzed: degree of cumulus cells expansion; oocyte morphology and the functional status of lipidome in female gametes (fluorescence intensity of Nile red /lipid droplets complex - FILDs).

Results. The addition of SDMG into cryoprotective media reduced the level of denuded oocytes after vitrification. The level of gamete with different degree of cumulus cells expansion (low, medium, high) in the experimental group with 10 % SDMG tended to indicators in the group of native cells. The level of native oocytes with the signs of morphological degeneration (7.7%) had no significant differences with the level of intraovarian vitrified gametes with 10 % SDMG (11 %). The proportion of native oocytes with low FILDs (38.9 %) exceeded the level of oocytes with the above indicator in vitrified oocytes of the control (16.5 %) group and in experimental groups of cells with the addition of 6 % SDMG (4.8 %) and 10 % SDMG (11.8 %, P<0.001).

Conclusion. In general, comprehensive monitoring of indicators cryoresistance of COCs in Sus scrofa domesticus subjected to intraovarian vitrification revealed the cryoprotective properties of SDMG. The effects were dose-dependent and were expressed in the stabilization of oocyte-cumulus communication, a decrease in the level of oocytes with the signs of morphological degeneration, and features of the lipidome functioning in intraovarian vitrified female gametes using SDMG at various concentrations.

Objective: to evaluate the nuclear maturation ability of pig oocytes in relation to the morphology of the surrounding cumulus cells, the duration of in vitro maturation (IVM) and the physiological status of cumulus-oocyte complexes (COCs) donor animals.

Materials and methods. СOCs collected from cycling (pubertal) and non-cycling (prepubertal) pigs ovaries were categorized according to the number of cumulus cell (CC) layers: COC I – more then 4, COC II – 3-4, COC III – 1-2 and СOC with granulosa cells (GCOC). Oocytes within COCs were matured during the first 22 h of culture in the TC-199 medium with 25 mM HEPES, 3.05 mM D-glucose, 0.91 mM sodium pyruvate, 0.57 mM cysteine, 0.4% BSA, 10% follicular fluid, 0.5 μg/mL FSH, 0.5 μg/mL LH and 50 μg/mL gentamicin sulfate and thereafter in medium of the same composition but without hormones. After 42, 44, 46, 48 hours of culture the maturation of oocytes of all categories and age groups was assessed by the sign of their release of the first polar body.

Results. It was shown that at least 42 hours of in vitro culture of pubertal pig oocytes are required to ensure a high level of nuclear maturation. The duration of the in vitro maturation was found to be 44-48 hours for pre-pubertal pigs. Oocytes surrounded by 1-2 layers of CC, when cultured for less than 48 hours, are inferior in nuclear maturation to oocytes with a more multilayered cumulus. The presence of GC (granulosa cells) around COC retards retards the progression of nuclear maturation when cultured for less than 42 hours in prepubertal and 44 hours in pubertal gilts. Oocytes from cycling pigs reach peak maturation earlier than those from non-cycling gilts and can be used in assisted reproductive technologies (ART).

Conclusions. It was concluded that both morphology of the surrounding cumulus cells and physiologic status of COC donor animals should be considered when choosing the duration of pig oocytes culture for the purpose of their in vitro maturation.

The growth of the world's population implies the search for alternative sources of nutrition. One such area is the development of aquaculture. The world aquaculture, as well as other branches of agriculture, has gone through stages of its formation from farming by primitive methods to use of modern technologies. Salmon farming occupies an important place in industrial fish farming, and the volume of farmed products is increasing every year. This review summarises the main milestones in the salmon aquaculture industry, describes the trends that have guided breeding programmes and shows the genetic approaches that have been used in fish farming. The introduction of genetic methods in salmonid fish breeding depends on the level of development of the countries where fish farms are located. Abroad there is a great experience of investment policy aimed at creation and introduction of projects up to the final (operational) stage of introduction of molecular genetics methods into salmon breeding, including the use of genomic selection. While in Russia the concept of genetic improvements in aquaculture is only being discussed.  In this review an important place is given to generalisation of the accumulated material on genetic methods of salmonid fish research, as well as directions of application of genetic markers in salmon farming. The issues of searching for candidate genes, quantitative trait loci (QTL) associated with gaining muscle weight and fish resistance to diseases are discussed.  The directions and ways of solving breeding problems are shown. Intensive development of scientific approaches to aquaculture development abroad is a vector for setting goals to expand business investment in the development of molecular genetic approaches to salmonid fish breeding in Russia.

Purpose: the study of economic and significant indicators of the Koryak ecotype of the northern deer.

Materials and methods. The model for the study of the Koryak ecotype was the livestock of animals in agricultural enterprises for breeding the northern deer in the Kamchatka Peninsula during the stable development of the industry, with a total number of more than 125 thousand individuals. The entire number of deer was contained in 86 herds, on average in one herd, up to 1,400-1500 animals fell. Zootechnical information was taken from annual reports of deer farms. In the study of farms, indicators used in the reindeer husbandry industry were taken: the number of deer at the beginning of the year; the uterus in the structure of the herd (the number of important and heels in % to the total number of deer); offspring - received living calves at the end of the hotel per 100 uterus, %; DWT - a business exit of calves at the end of the year per 100 uterus, %; SVP - the safety of the adult number of deer at the end of the year, %; Production of meat in live weight, taking into account growth per 100 January deer, in C; Live weight of sexual age groups, kg.

Results. The reindeer husbandry of the territory was distinguished by high quality indicators. The specific gravity of the uterus in the structure of the herd was maintained at 60 % and higher. The deer of this ecotype has good reproductive properties, on average at the end of the hotel there were more than 86 calves per 100 queens. The business yield of young animals at the end of the year on average ecotip was 80.6 % with fluctuations from 73 to 86.5 %, which confirms the high reproductive properties and viability of the young deer group of the northern deer. The safety indicator of the adult livestock at the end of the year was at the level of 93.9 % with fluctuations in individual populations from 90.4 % to 96.5 %. The production of meat in live weight, taking into account the growth of 100 deer according to individual scope, was flukes from 28 to 31.5 c, with an average ecotype value over 29.2 c. In terms of live weight of the Koryak ecotype deer, they exceeded the analogues of the sexual age groups of deer in the Chukotsk AO by 1.0-7.7 %, which confirms their high household chores. When crossing the deer of the Koryak ecotype and the Chukotka breed, a manifestation of heterosis was noted, since the estates significantly exceeded both initial parental forms in live weight, the preservation of the livestock, the business exit of young animals increased, and the production of meat increased. The identification of highly productive ecotypes and the creation on their basis of in -breed structures will increase the productivity of the northern deer.

In this article, the content of micro- macroelements in dry and juicy feeds is studied to increase the productivity of animals and it is essential to take measures to prevent diseases caused by a deficiency of macro-microelements in the diet of animals. To increase productivity, it is essential to prevent diseases caused by a deficiency of minerals in the diet of animals. In Yakutia, where cattle breeding and horse breeding are engaged, animal diseases associated with impaired metabolic processes in the body are widespread. Macro-microelements, which are important for the animal body, must be in the necessary quantities and constantly. In the body, they are involved in the formation of biologically highly active substances, such as hormones, vitamins and enzymes. With a lack or excess of these trace elements in the soil, feed, water, specific metabolic diseases arise and develop in animals, leading to a decrease in productivity, reproduction and even death. The most common is endemic goiter caused by a lack of iodine, white muscle disease caused by a lack of selenium, anemia caused by a lack of iron, etc. Therefore, the authors of the article consider the deficiency of minerals, macro- and microelements in the diet of animals to be one of the most acute problems in modern animal husbandry in Yakutia.

The critical population for the existence of the Taimyr population of wild reindeer has been established. The processing of the initial information about the population size was performed using the apparatus of mathematical biology. The main practical task is to identify the lower limits of abundance and the critical load for the population, after which the collapse of this commercial population will occur. Also, regression equations were calculated for the total livestock of the population, the reproductive core (mature females) and juveniles (calves of the year) at different time intervals of the economic use of the resources of this population - Soviet and post-Soviet. For the Soviet period of using the resources of the population in 1969-1990 the parameters of the equation look like: y = 21.867x + 316.77 thousand (R2 = 0.886, Ᾱ = 6, rxy= - 0.41, p<0.05). For adult females, the trend equation for this segment of the reproductive cycles: y = 5.157x + 73.879 thousand, (R2 = 0.836). The total number of the population did not decrease: the average realized reproduction in this segment of the biological cycles is 61 calves per 100 mature females. In the post-Soviet period 1990–2021 equation of the linear trend of the Taimyr population: y = - 36.96х + 624.51 thousand (R2 = 0.75, Ᾱ = 5.18, rxy = 0.46, р<0.05). Evaluation by the straight-line trend equation of the juvenile group (calves of the year) gives a negative calculated value of the linear regression equation within y = - 21.4x + 175.51 thousand. (R2 = 0.944, Ᾱ = 2.9, rxy = 0.98, p<0.01). Such facts unequivocally signal the excess of the optimal intensity of fishing, because there is a gradual decrease in recruitment. The estimated critical number of the Taimyr population is 88.77 thousand wild deer, the critical limit of the fishery with a similar number is the removal of 71.9 thousand individuals. From here, hypothetically, only 16.87 thousand heads remain from the Taimyr population, which will lead to the collapse of this biological population.

The critical population for the existence of the Taimyr population of wild reindeer has been established. The processing of the initial information about the population size was performed using the apparatus of mathematical biology. The main practical task is to identify the lower limits of abundance and the critical load for the population, after which the collapse of this commercial population will occur. Also, regression equations were calculated for the total livestock of the population, the reproductive core (mature females) and juveniles (calves of the year) at different time intervals of the economic use of the resources of this population - Soviet and post-Soviet. For the Soviet period of using the resources of the population in 1969-1990 the parameters of the equation look like: y = 21.867x + 316.77 thousand (R2 = 0.886, Ᾱ = 6, rxy= - 0.41, p<0.05). For adult females, the trend equation for this segment of the reproductive cycles: y = 5.157x + 73.879 thousand, (R2 = 0.836). The total number of the population did not decrease: the average realized reproduction in this segment of the biological cycles is 61 calves per 100 mature females. In the post-Soviet period 1990–2021 equation of the linear trend of the Taimyr population: y = - 36.96х + 624.51 thousand (R2 = 0.75, Ᾱ = 5.18, rxy = 0.46, р<0.05). Evaluation by the straight-line trend equation of the juvenile group (calves of the year) gives a negative calculated value of the linear regression equation within y = - 21.4x + 175.51 thousand. (R2 = 0.944, Ᾱ = 2.9, rxy = 0.98, p<0.01). Such facts unequivocally signal the excess of the optimal intensity of fishing, because there is a gradual decrease in recruitment. The estimated critical number of the Taimyr population is 88.77 thousand wild deer, the critical limit of the fishery with a similar number is the removal of 71.9 thousand individuals. From here, hypothetically, only 16.87 thousand heads remain from the Taimyr population, which will lead to the collapse of this biological population.

Purpose:  the aim is to study the effect of the inclusion of the immunomodulator thymalin in the treatment regimen of genital mycoplasmosis of cattle on the immunological characteristics of vaginal secretions.

Materials and methods. For the experiment, three groups of pregnant cows were formed, 8 heads each. The first group – pregnant cows with genital mycoplasmosis for the treatment of which the antibiotic traksovet 100 (tulatromycin) was used at a dose of 2.5 mg per 1 kg of animal body weight, subcutaneously, once 40 days before the expected delivery. The second group - pregnant cows with genital mycoplasmosis for the treatment of which the antibiotic traksovet 100 was used at a dose of 2.5 mg per 1 kg of animal body weight, subcutaneously, once 40 days before the expected delivery and the immunomodulator timalin at a dose of 0.1 mg per 1 kg of animal body weight, intramuscularly, twice with an interval of 72 hours. The third group (control) – clinically healthy pregnant cows. In experimental groups of cows, 2 weeks after the start of treatment, the effectiveness of therapy was monitored by conducting a PCR test for Mycoplasma spp. Before the start of therapy, vaginal secretions were collected from the walls of the vagina in animals of all groups. Repeated secretion from the first and second experimental group of cows was carried out 14 days after the start of treatment. In vaginal secretions, the content of - Ig G, Ig M, Ig A, sIg A and their total amount were determined by radial immunodiffusion in Mancini gel, lysozyme activity and its reaction (pH) was determined.

Results. In the group of animals for the treatment of which the traxovet was used 2 weeks after the start of therapy, Mycoplasma spp. it was detected in 2 cows out of 8 (therapeutic efficacy was 75 %); in a group of cows where traxovet was used in combination with thymalin positive tests for Mycoplasma spp. there was no (therapeutic efficacy – 100 %). The use of an antibiotic for the treatment of cows with mycoplasmosis leads to the restoration to the level of healthy animals only Ig M and sIg A, whereas, when included in the thymalin therapy regimen, all the studied indicators reached their values in healthy cows.

Conclusion. The use of a combination of tulatromycin and thymalin for the treatment of cows with genital mycoplasmosis provides a higher percentage of recovery, and also contributes to the restoration of the immuno-biological properties of vaginal secretions.

Mastitis in high yielding lactating cows is the most common disease that causes enormous economic damage to livestock farms. According to leading scientists, when studying the problem of mastitis, the greatest interest is in studying the dynamics of changes in the immunological blood indicators of cows during the occurrence and development of the inflammatory process in the udder. To conduct research, three groups of lactating Holstein cows of 2–3 lactations with an annual milk production of 7356–8000 kg of milk, belonging to one of the farms in Voronezh region, were formed. The first group (n=8) included clinically healthy animals, the second (n=8) - cows with subclinical mastitis, the third (n=8) - cows with clinically pronounced catarrhal mastitis. Blood samples were taken from all animals to determine immunobiochemical and molecular genetic indicators. The studies have established that the level of expression of the genes for the pro- and anti-inflammatory cytokines IL-10 and IL-4 was by 2.6 and 1.5 times lower, respectively, in the cows with subclinical mastitis and by 5.8 and 3.9 times lower in the cows with clinically pronounced catarrhal mastitis, respectively, in comparison with clinically healthy animals. At the same time, the expression of pro-inflammatory INF-γ was by 7.6 and 14.8 times higher in the cows with subclinical and catarrhal mastitis, respectively, compared to clinically healthy animals.

Purpose: to study the forms of clinical manifestation and features of the course of postpartum metritis of inflammatory diseases of the uterus in highly productive cows of different breeds with free-stall and traditional technologies of their operation. The novelty of the work lies in the fact that for the first time the distribution and forms of clinical manifestations of postpartum metritis in cows of different breeds were studied under free-stall and traditional housing technologies.

Materials and methods. The degree of distribution, forms of clinical manifestation and features of the course of postpartum metritis in highly productive cows of different breeds (n = 5345) were studied using traditional and free-stall technologies of their operation. To study the above indicators, anamnestic and veterinary data were used. Clinical and obstetric examination was carried out using generally accepted methods: transrectal palpation and ultrasound sonography, in accordance with the “Methodological manual for the prevention of infertility in highly productive dairy cattle”.

Results. As a result of the studies, it was found that obstetric pathology is registered on average in 71.3% of new-born animals. The most frequently affected animals were the Holstein breed with an annual milk yield of 7500-8500 kg. They were diagnosed with postpartum metritis in 78.0-86.4 % of cases of the number of calvings. In cows of the Simmental breed of domestic selection with tether housing technology and an annual milk yield of 4000 to 5300 kg, obstetric pathology was recorded much less frequently, in the range of 59.3-65.1%. In highly productive Holstein cows, severe forms of the inflammatory process most often developed: purulent-fibrinous - in 12.4 %, purulent-necrotic - in 13.2 %, gangrenous - in 1.1 %, postpartum sepsis - in 0.8 % of cases , whereas it was not diagnosed in animals with traditional exploitation technology. The more frequent manifestation of severe forms of this disease in highly productive animals may be associated with a decrease in the general nonspecific resistance of their body. In 65.7%, postpartum metritis occurred in an acute form, regardless of the breed and conditions of detention.

Purpose: сomparing the effectiveness of the proposed protocols for the treatment of cows with acute postpartum endometritis and establishing the effectiveness and the terms of their subsequent insemination.

Materials and methods. 47 Cows of the Holstein-Frisan breed, which are on the binding content, were examined. All these animals were provided with obstetric care. As a result of their clinical inspection, 16 goals with an acute form of postpartum endometritis were revealed. Of these animals, two groups of 8 goals formed in each on the principle of pairs of analogues. When making a diagnosis, anamnesis, clinical signs of the disease and the results of an ultrasound of the study were taken into account. The first group included animals whose treatment regimen included intrauterine administration of Tilocar and intramuscular Uteroton. In the second group of cows, a 0.5 % Novocaine solution was additionally injected intravenously, according to the instructions.

Results. The study revealed that the animals in the second group recovered three days faster (11.13±0.39 days) than the first group (14.25±0.37 days). We used the odds ratio. The second group of cows, where an additional 0.5 % of the Novocaine solution was administered, was found to be 2.78 times more likely to become pregnant than those treated without it.

 This article examines the genetic diversity of Momsky horses using seventeen microsatellite markers. The analysis revealed that the average locus polymorphism level was 3.384 units, while the AHT4 locus showed the highest polymorphism. Different loci had varying numbers of effectively acting alleles. There was an excess of total alleles over the number of effectively acting alleles by more than 1.5 times, indicating significant genetic variability in the population of Momsky horses. The study confirmed significant heterozygosity variation at both the overall sample level and for individual loci. Certain loci exhibited a deficiency of heterozygotes, while others demonstrated a predominance of observed heterozygosity over expected heterozygosity. The LEX3 locus had the lowest level of observed heterozygosity (0.312), while the AHT4 locus showed the highest level (0.844) of expected heterozygosity. Data analysis also enabled the determination of the equilibrium distribution of heterozygotes. Five loci - HMS1, CA425, HTG6, VHL20, ASB17 - had a distribution of heterozygotes close to equilibrium, while seven loci displayed a deficiency of heterozygotes. The most pronounced deficiency of heterozygotes was observed in the LEX3 locus. The remaining loci showed varying degrees of dominance of observed heterozygosity over expected heterozygosity. The importance of genetic diversity in horse populations is emphasized, particularly in the context of breeding programs. Maintaining a certain level of genetic diversity plays a crucial role in population adaptation to changing environmental conditions and ensures long-term survival.

Purpose: to characterize the allele pool of sheep of the southern beef breed using microsatellites.

Materials and methods. The biomaterial was ear’s plucks from 80 sheep of the southern meat breed, selected from the Ladozhsky Breeding Plant. 20 East Friesian sheep, 33 Dorset sheep and 63 Romanov sheep were used for comparison. Nine microsatellite loci (INRA005, SPS113, INRA23, MAF65, McM527, OarCP49, HSC, OarAE129, MAF214) were selected as DNA markers. Microsatellite variability was analyzed using the ABI3130x1 Genetic Analyzer. The results were processed in the GenAIEx 6.503 program, with the help of which the main indicators characterizing the state of the allele pool and genetic diversity were calculated.

Results. Analysis of the population genetic parameters of sheep of the southern meat breed showed that the average number of alleles per locus (Na) and the effective number of alleles per locus (Ne) exceed the sample average by 1,72 and 0,58 alleles, respectively. The expected heterozygosity (He) was 0,766, while the observed heterozygosity (Ho) was 0,741. The coefficient of inbreeding (Fis) was 0,03. The analysis of the principal components, carried out for the studied breeds in the planes of the first and third principal components, did not fundamentally change the nature of the spatial clustering of the studied groups of sheep. Analysis of the principal coordinates, performed on the basis of calculation of pairwise Fst values, showed that the southern meat breed is located in the upper left quadrant and is isolated from other breeds. The values of the Fst indicator indicate that there is moderate genetic differentiation between the southern meat and dorset breeds (Fst=0,116), and significant genetic differentiation between the southern meat and romanov breeds (Fst=0,161).

Conclusion. An analysis of the population genetic parameters of sheep of the southern meat breed, in comparison with the east friesian, dorset and romanov breeds, showed that, in general, in terms of the total number of alleles per locus and the number of effective alleles per locus, it is characterized by a high level of genetic diversity. The presence of a tendency towards a deficiency of heterozygotes is probably explained by the limited population, represented by the only relict gene pool in Russia.

In black-and-white cows with reduced fertility, during the dry and early post-calving periods, changes in the functioning of the thyroid system are observed, which differ from those in individuals with high fertility. Such changes may lead to a lack of energy sources during the critical transition period.

Purpose: To study the dynamics of changes in the lipid content before and after calving and its association with the content of thyroid hormones in the blood of black-and-white cows with various fertility.

Materials and methods. Black-and-white cows of lactation 2-4 were used in the study. The animals were bled 6, 4 and 2 weeks before calving and 1, 3, 7 and 13 weeks after calving. In blood serum samples, the content of lipids was determined using a biochemical analyzer, as well as thyroid hormones and progesterone using ELISA. Cows were inseminated after treatment according to the Ovsynch protocol, and pregnancy was assessed on Day 33 based on ultrasound examination and progesterone levels in the blood.

Results. The cows were divided into two groups: I – pregnant individuals (n=17) and II – individuals that remained infertile (n=12). The milk productivity of animals and their BCS before and after calving were similar in the compared groups. Thirteen weeks after calving, the cholesterol content in the blood of cows of group II was 1.2 times lower (p<0.05) compared to this content in animals of group I. At the same time, 6 weeks before calving, the concentration of phospholipids in the blood of individuals of group II was 1.3 times higher than that of individuals of group I (p<0.05). In addition, 3 weeks after calving, the level of triglycerides in cows of group I was 1.2 times higher (p<0.05) than that in animals of group II. During the postpartum period, the blood levels of cholesterol and triglycerides in animals of group I positively correlated with the content of total thyroxine, whereas such a correlation was not detected in group II.

Conclusions. Thus, the metabolic state of cows with higher fertility was characterized by an increased supply of lipid energy sources during the post-calving period compared to animals with low fertility. At the same time, the reduced content of triglycerides at the early stage of lactation in the blood of cows that remained infertile points to their increased accumulation by the liver. A positive relationship between the concentration of total thyroxine in the blood and the concentration of triglycerides and cholesterol, revealed during the post-calving period in cows with high fertility, suggests the participation of the thyroid hormone in maintaining the reproductive function of these animals by modulating lipid metabolism.

In the last decade, a new promising direction to reduce the risk of T-2 toxicosis at domestic poultry enterprises has been the rational use of antioxidants in the formulation of compound feeds. The purpose of the research is to determine the effect of the antioxidants santoquin (santoquin) and vitamin E in the composition of feed based on wheat grain, sorghum and rapeseed meal with a tolerant level of T-2 toxin on the state of intermediate metabolism and anti-radical protection of the body of meat quails. We have substantiated new data on the advisability of jointly introducing the antioxidants santoquin at a dose of 150 g/t and vitamin E at a dose of 25 thousand IU/t of feed into the composition of feed based on wheat grain, sorghum and rapeseed meal with a tolerant level of T-2 toxin to optimize the meat quail hematopoietic function of the body. The tested antioxidants, when fed in combination, contributed to the improvement of protein, carbohydrate, lipid and mineral metabolism in quails of the 3rd experimental group. Due to the synergistic effect of antioxidants in the composition of diets, an increase in protective functions in the body of quails of the 3rd experimental group was noted due to an increase in lysozyme activity in blood samples by 3,00% (P>0,95) and bactericidal activity - by 8,30% (P>0,95) than in the control group. While ensuring better detoxification of T-2 toxin in comparison with control analogues, meat quails of the 3rd experimental group improved the antioxidant defense of the body due to an increase in the enzymatic activity of glutathione reductase in the blood by 25,34% (P>0,95), alkaline phosphatase - by 18,34% (P>0,95) with a parallel decrease in catalase activity - by 9,54% (P>0,95), the level of conjugated dienes - by 2,28 times (P>0,95) and malondialdehyde - by 1,33 times (P>0,95).

In the process of maintaining the metabolic processes of the gastrointestinal tract of ruminants, an important link is to ensure a complete feeding diet. The study of the use of betaine supplements in a form "protected" from the indirect effects of the microflora of the rumen showed positive dynamics in relation to the digestive processes, the microbial composition of the rumen and the intestines of sheep. In the conditions of the physiological yard of the Federal Science Center for Animal Husbandry named after Academy Member L.K. Ernst conducted a physiological experiment on ramshanks of crossbreeds of the Romanov breed and katadins, aged 8-9 months, with chronic scar fistulas according to Basov (n=3). In the control period, the animals received the main diet, in the experimental 1 – the main diet + unprotected betaine at a dosage of 0.05 g / kg of live weight, in the 2nd experimental period a "protected" betaine supplement at a dosage of 0.05 g / kg of live weight. The duration of each period was 30 days. During the accounting period, average daily stool samples were taken according to the generally accepted method. To study cicatricial digestion, at the end of each period, samples of the contents were taken from animals through the fistula of the scar by Basov. As a result of the use of both the "protected" and native forms of betaine, the mass of microorganisms of the scar content became higher than in the control period. When the "protected" form of betaine was added to the diet of animals, the overall digestibility of feed nutrients tended to improve. In the 2nd experimental period, compared with the control, the level of bifidobacteria in the large intestine of sheep increased by 1.63 CFU/g, the level of pathogenic yeast fungi decreased several times.

The review reveals the current state of knowledge of the plasma membranes molecular composition of rooster spermatozoa and its role in maintaining the morphofunctional integrity of cells under low-temperature stress.  The use of the method of cryopreservation of the semen in poultry breeding is still in the field of scientific development, since the level of fertility of the frozen-thawed semen is not high enough to be used for application in the commertial poultry flocks. When solving the problems of improving the quality of thawed roosters semen  it is necessary to rely on the effectiveness of cryoprotective media, as well as to determine the most vulnerable organells of structure of the spermatozoa apparatus during freezing. Rooster spermatozoa are surrounded by a unique plasma membrane, which includes a high content of polyunsaturated fatty acids (PUFAs), sterols, a number of phospholipids, glycolipids, which play an important functional role in the interactions between spermatozoa and oocytes and affect their ability to fertilize. The study of the lipid composition of the cell plasma membranel and its dynamic state is necessary to identify the key factors of cell cryoresistance; the manifestation of their quantitative and qualitative changes may indicate a possible degradation occurring inside the cells under conditions of low-temperature stress. This review presents the results of studies proving the exceptional role of the lipid composition of spermatozoa membranes in the mechanisms of cell cryoresistance and the preservation of their morphofunctional usefulness under thermal stress.

Purpose: to study the bioelectrical activity of the brain and determine the parameters of electroencephalograms in sports and untrained horses.

Materials and methods. The object of the study were horses aged from 2 to 20 years in the amount of 150 heads. The animals were in active training and were also used for rental training in horse riding; their average weight was 550.78 kg; the breeds were Oryol Trotter, Russian Trotter, American Trotter and Hanoverian. During EEG recording, horses were restrained using a halter at the junctions. Experiments were carried out in the morning or afternoon, 1 hour before feeding/training or 1 hour after. EEG registration was carried out with patch electrodes in 6 unipolar leads using a special patented Ippolitova / Gauss helmet for recording EEG in animals, the electrodes on which are located along the projections of different lobes of the brain, which allows non-invasively, without the use of sedatives and shaving hair, to record the electrical activity of the brain . EEG recording continued for 10-15 minutes. We assessed brain rhythms using the following indicators: Rhythm severity index (RSI) – the degree of manifestation of the rhythm, the percentage of time during which a given rhythm is recorded (%). Frequency – the number of complete oscillations performed per unit of time, sec. (Hz). Amplitude is the largest deviation (from the average) value of a quantity, the range of oscillations.

Results. As a result of the research and analysis of the obtained EEG data, waves of bioelectrical activity of the brain in horses were established in the following ranges: alpha rhythm (α-rhythm) – 7.1 – 13 Hz, amplitude up to 100 µV; beta-1 rhythm (low-frequency β-1 rhythm) – 13.1 – 25 Hz, amplitude – 3-5 µV; beta-2 rhythm (high-frequency β-2 rhythm) – 25.1 – 40 Hz, amplitude – 3-5 µV; delta rhythm (δ rhythm) – 0.3 – 4 Hz, amplitude up to 40 µV; theta rhythm (Ѳ-rhythm) – 4.1 – 7 Hz, amplitude about 30 µV; gamma rhythm (γ rhythm) – above 40.1 µV. When analyzing EEG rhythms in animals, the most pronounced spontaneous brain activity at rest in the horses studied is the delta rhythm in all leads and hemispheres. We observe oscillations with a frequency of 0.3–4 Hz and an amplitude of up to 40 μV. The waveform is regular, sinus. Such oscillations represent the delta rhythm.

Purpose: to study the effect of antioxidants santoquine and vitamin E, included in the composition of wheat-sorghum-rapeseed type feed with a tolerant level of T-2 toxin, on the productivity and digestive processes of meat quail.

Materials and methods. The experiment was carried out on meat quails of the Pharaoh breed. At one day of age, according to the principle of analogous groups, 4 groups of 40 animals each were formed. Raised for meat until 42 days of age. Quails were individually weighed weekly to determine live weight gain and calculate feed costs per unit of production. After control slaughter at the age of 42 days, the activity of digestive enzymes: proteinases, amylases and cellulases was studied in the contents of the muscular stomach and duodenum of 5 animals from each group.

Results. In the course of the studies, new experimentally substantiated data were obtained on the effectiveness of reducing the risk of T-2 toxicosis in the body of meat quails due to the rational joint use of santoquin antioxidant drugs in the composition of mixed feeds of the wheat-sorghum-rapeseed type with a tolerant level of T-2 toxin at a dose of 150 g/ t and vitamin E at a dose of 25 thousand IU/t. Thanks to this, in the quails of the 3rd experimental group, there was an increase in the survival rate of the livestock by 7.8 %, and an increase in live weight by 13.19 % (P<0.05). The meat poultry of the 3rd experimental group had the best pay for feed in terms of live weight gain, having spent 12.01 % less feed to obtain 1 kg of gain compared to the quails of the control group. Combined additions of the tested antioxidants contributed to a significant (P<0.05) increase in the activity of proteinases, cellulases and amylases in the contents of the muscular stomach by 24.15, 33.30 and 18.18 % and in the duodenum - by 13, compared to the analogues of the control group. 58, 13.93 and 15.02%, respectively.

The aim of this work was the systematization and analysis of scientific data on cryoresistence of sperm of various types of animals and factors affecting the cryorezistivity of sperm. Sperm cryoresistence is the stability of sperm to the effects of low temperatures. Cryoresistence is evaluated according to the morphological characteristics of sperm, their activity and mobility after thawing, the integrity of the acrosomes, the plasma membrane and the degree of damage to chromatin. Cryoconservational is an important component of artificial insemination of animals, and knowledge about the cryorezistence of spermatozoa is the theoretical basis for the successful cryoponement of sperm. Based on the listed studies, cryoresistence has species features and depends on: the age of animals, pedigree features, season of the year, concentration of testosterone and prolactin in the blood, temperature and humidity index, as well as from cryoconservative protocols.