The study aimed to investigate the genetic variability of the Gashun Soviet Merino sheep breed, determining myostatin (MSTN) and calpastatin (CAST) gene polymorphism by the PCR-RFLP method. Earmark samples were collected from 200 animals, and DNA was isolated using a commercial kit. The MSTN gene had A and G allele frequencies of 0.33 and 0.67, and the CAST gene had M and N allele frequencies of 0.83 and 0.17, respectively. The frequencies of the AG and GG genotypes for MSTN and MM and MN for CAST were 0.66 and 0.34, respectively, in both. Genetic equilibrium was maintained for the CAST gene (χ²=4.1951). For the MSTN gene, the Hardy-Weinberg equilibrium was violated (χ²=24.2). The pre-slaughter body weight, hot carcass weight and slaughter weight were higher in CAST_MN genotype than CAST _MM by 4.8%, 6.5%, and 6.4%. The hot carcass and slaughter weights of lambs with the MSTN_AG genotype were higher than MSTN _GG by 4.7% in both. However, the pre-slaughter weight in the animals with the MSTN _GG genotype was higher by 3.4%. Data on the CAST and MSTN gene polymorphism and the genetic structure of the studied sheep population were obtained for the first time, their association with slaughter traits was revealed, and desirable genotypes CAST_MN and MSTN_AG were determined. The Na, Ne, Ho, He, FIS and χ2 values obtained and the absence of individuals with CAST_NN and MSTN_AA genotypes substantiated the prospect of further use of these genes in programs of genetic livestock improvement.

One of the main tasks in sheep breeding is to increase productivity. The use of DNA markers for the selection of animals containing the desired alleles of genes of economically valuable traits is one of the new scientific approaches to solving this problem. The aim of the work was to study the genetic structure of sheep of various breeds by genes GDF9, GH, CAST. The studies were carried out on the basis of the laboratory of molecular diagnostics and biotechnology of farm animals of the Don State Agrarian University and the Center for the collective use of scientific equipment “Bioresources and bioengineering of farm animals” of the All-Russian Scientific Research Institute of Animal Husbandry named after academician L.K. Ernst. To carry out molecular genetic studies, samples of ear pits (tissue from the auricle) with an area of 1 cm² were taken from sheep. The evaluation was carried out by PCR-RFLP method. As a result of DNA genotyping for genes GDF9, GH, CAST, the genetic structure of sheep of such breeds as: Salskaya, Stavropol, Volgograd and Soviet merino was revealed. A and B allelic variants of the GDF9 gene, alleles A and B of the GH gene, alleles A and B of the CAST gene were identified in all studied groups of sheep. Analysis of the data revealed the breed aspect in the distribution of the allele and genotype frequencies of the GDF9, GH, CAST genes in the populations under consideration.

The paper presents the findings on the morpho structural diversity of sheep placenta, depending on such factors as age, exterior and physique characteristics, breeds, ewes prolificacy that are fundamental in assessing progeny viability. The experiment involved the ewes of the Caucasian and North Caucasian meet-and-wool breeds inseminated by the rams of the same breeds as well as the Texel, Poll Dorset, Edilbay and their progeny. The biomaterial for the research was the placenta and blood of the experimental animals. Ewes aged 2.5 and 3.5 years had the lightest placenta – 165 and 172 gr, ewes aged 4.5 and 5.5 years had the heaviest placenta – 230 and 247 gr. It has been also determined that the most favourable age for gestation in ewes is 4.5-5.5 years. Interrelation of the placenta morphostructural parameters (placenta weight, the number and size of cotyledons) and the lambs live weight and productivity has been established. This allows us to view placenta as a bioscopic material for assessing and prediction of future sheep productivity at early age.

Currently, the food industry faces challenges that are not solved by a simple quantitative increase in production, but require qualitatively new approaches. The article discusses the possibility of using a prebiotic and collagen gel in the sausage production technology. The main task in the development of a new recipe for sausages was to use the best combination of prebiotic, collagen gel, raw meat and to expand the range of sausages, as well as to reduce the cost of the finished product. Fat reduction and prebiotic fortification are the main goals of the functional nutrition concept. Increased consumer interest in healthy eating contributes to an increase in demand for meat products with a reduced fat content, which poses a challenge for meat industry specialists associated with the important role of adipose tissue in forming consumer characteristics. Particular attention is paid to the substances that can replace adipose tissue in meat products. In this regard, it is important to use inulin, which, on the one hand, is a prebiotic, and on the other, it has technological properties that allow imitating fat in a product. The use of collagen gel improves economic performance of production by reducing production costs and losses during heat treatment and by rationalizing the use of low-grade meat raw materials. Experimental studies were carried out in the laboratory of the Department of Food Technologies of the Donskoy State Agrarian University. Basing on the research carried out, a recipe and a technological scheme for sausages production have been developed. Evaluation of the minced meat composition quality parameters indicates that the minced meat composition containing 80% of poultry meat, 15% collagen gel and 5% inulin, has a high degree of protein and fat balance. On the basis of organoleptic and physicochemical studies, a rational formulation of the product is proposed. An improvement in organoleptic and rheological characteristics has been established. The optimal dose of prebiotic and collagen gel introduction into the developed sausages has been substantiated. Studies have shown that the production of cooked sausages using a prebiotic and collagen gel is a promising direction.

The article discusses methods for the effective use of the Soviet Merino sheep gene pool in order to increase the level and quality of meat productivity. Analys The article discusses methods for the effective use of the Soviet Merino sheep gene pool in order to increase the level and quality of meat productivity. Analys

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