Meeting the growing needs of consumers in quality food products with dietary and high palatability is possible by increasing the production of capon meat (gonadectomy roosters). The purpose of the work is to study the fractional composition of blood plasma proteins, average daily body weight gains, slaughter rates and the quality of meat of Adler silver roosters after gonadectomy. It has been shown that the blood plasma of the Adler silver cocks contains more than 20 different protein fractions, the molecular weight of which is in the range from 17 to 260 kDa. After gonadectomy, the content of proteins with low molecular weights (fractions D, H, L, P) in the blood plasma of roosters decreased, the level of individual high-molecular proteins (fractions C and E) increased, and the remaining fractions did not change compared to the control. It was found that the body weight of gonadectomized roosters on the 185th day of the experiment was 6.4% higher than in the control group, as well as the average daily body weight gain, which was on average 8% higher than that of the control group roosters. The weight of half-gutted and gutted carcasses after slaughter of gonadectomy roosters was higher than in the control by 7.5 and 9.0%, respectively, and the heart, liver and muscular stomach did not change. An increase in the number of microbial cells by 57.1% in smears-imprints of the pectoral muscle and by 68.4% in the muscles of the thigh of gonadectomy roosters after four days of storage of carcasses compared with the control was established. Other indicators of microbial contamination of the pectoral and thigh muscles of gonadectomy roosters, as well as the pH of the water extract and the amount of MAPAM did not exceed their value in the birds of the control group and met the requirements. In samples of the pectoral muscle and thigh muscle of gonadoectomized and roosters of the control group, the reaction to peroxidase was positive, and CGB, pathogens of salmonellosis, listeriosis and coagulopositive staphylococci were not isolated.