Changes in the microflora and histological structure of the sterlet intestine during feeding with aquafoods with haprin

The problem of providing a full-fledged protein component in fish feeding, as well as reducing the cost of aquaculture feeds in the aquaculture industry, is quite acute, and therefore its replacement ingredients are introduced into fish diets instead of the basic component-fish meal. A study on the use of haprin in sturgeon diets has been conducted since 2022. The aim is to study the effect of the product of microbial synthesis of haprin on the microflora and histological structure of the intestines of fish. The object of the study was the juvenile sterlet. The study was carried out on the territory of the basin workshop of the center "Breeding of valuable Sturgeon breeds" of the FSBEI VolSAU. It was noted that the introduction of haprin into aquaculture for juvenile sterlet had no negative effect on the intestinal microflora: the total number of microorganisms ranged from 105 to 107 cells/gram. Representatives of the genus Clostridium accounted for 103 and 105 cells/gram. Pathogenic microorganisms such as Peptostreptococcus and Staphylococcus in the studied sterlet intestinal samples were below the limit of reliable detection. The contamination with fungi of the genus Candida was low, with an average number of 103 cells/gram. It was found that the intestinal length index was the highest in all aquatic organisms of experimental groups 2, 3 and 4 in relation to the 1st control group by 7.53%, 14.05 and 15.46%. It was noted that the mucous surface of the inner intestinal lining of the experimental sterlet was covered with a large number of small papillae and intestinal villi, which indicates the intensification of nutrient absorption processes and confirms the fact of feeding high-quality balanced aquaculture feeds with a correctly selected granulometric feed composition. It was revealed that there were no pathological changes in the intestinal samples of experimental sturgeons. The safety of the research objects was 100%.