This paper presents a study of the processing of collagen-containing raw material and its changes in the course of targeted complex processing by hydrolysis, including freeze-drying. The pH, chemical composition, penetration magnitude, and critical shear stress were determined. The dried samples were examined using Fourier-transform infrared spectroscopy, and their microstructures were characterized. The characteristic property of the product developed was determined to be the presence of a relatively homogeneous fibrillar structure that promotes the functional capacity of the proteinoid-forming fibres in the compositions of foods from different groups.

This paper presents the results on the study of melanocortin-4 receptor (MC4R) gene polymorphisms in sheep of the Karachai breed. AA, AG, and GG genotypes were determined to have allele frequencies of 47%, 37%, and 16%, respectively, indicating that allele A and the homozygous AA genotype occurred the most frequently. Analysis of the meat productivity of sheep, with respect to the MC4R genotype, showed a higher slaughter yield in sheep with the AA genotype compared to those with either the GG or AG genotypes. The variability at these loci provides a basis for controlling the meat productivity of sheep in the Karachai sheep population; therefore, this polymorphism should be monitored and melanocortin-4 receptor (MC4R) gene selection considered in pedigree farms.

Aim. To demonstrate the high adaptive abilities of dairy cattle to various ecosystems and natural zones of the Lower Volga at different times of the year. For the study we selected farms located in the steppe and semi-desert natural zones of the Volgograd region where animals of different breeds are reared.Material and Methods. Analysis was undertaken of the main indicators of raw milk quality, amino acid composition and environmental safety. Animals of all farms studied showed fairly high indicators of milk productivity in the climatic conditions of the Volgograd region, according to the standards of the breeds investigated.Results. The content of essential amino acids in cow milk for all groups varied depending on the breed and period of the year, generally reaching maximum values in winter. The calculation of amino acid scores showed that lysine is a limiting amino acid in animals of the Holstein-Friesian breed in the summer and autumn periods of lactation. The determination of chemical elements in milk during the summer period of lactation showed that all indicators are within acceptable concentrations, including heavy metals (lead, arsenic, cadmium, mercury).Conclusion. The research conducted confirms compliance of raw milk with standards in all farms studied for the main controlled indicators of quality and amino acid composition, content of chemical elements and allows recommendation of the milk produced for the production of all types of dairy and fermented milk products.

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.