The effect of supplementation of feeds with the probiotic “Subalin” on the productivity parameters sturgeon (Acipenseridae) hybrid bester on the first year of cultivation using warm waste water of a power plant

Purpose. To assess the effect of supplementing the feeds with the probiotic “Subalin” on the productive parameters of bester on the first year of cultivation using waste water from an energy installation (power plant) under conditions of elevated water temperature. Methodology. The study was conducted in 2023 in the conditions of an industrial-type farm “Biosila” created on the basis of warm waste water of a thermal power plant. Growing of age-0+ bester was carried out for 65 days in plastic tanks. They were fed with compound feeds manufactured by a well-known European manufacturer with a crude protein content of 54% and crude fat content of 15%. In addition to the main diet of the fish, a probiotic based on Bacillus subtilis “Subalin” was introduced at the rate (% of the weight of the feed): 0.02 (variant 1); 0.03 (variant 2); 0.04 (variant 3); 0.05 (variant 4). In the control variant of the experiments, the fish received the same compound feed without the probiotic. The stocking density of fish with an initial average weight of 22.8 g in all variants of experiments and control was 100 individuals in each tank (about 56 ind./m2). Determination of productive parameters and study of physico-chemical factors of the environment were carried out according to generally accepted methods. Findings. During the cultivation period of bester, water temperature fluctuated between 23.8–32.5°C. For 39 days, water temperature exceeded 30°C, which is uncharacteristic for sturgeon aquaculture. The content of dissolved oxygen varied from 4.0 to 5.7 mg O2/dm3. Other hydrochemical parameters met the requirements for growing sturgeons. As a result of intensive breeding, bester juveniles in various experimental variants reached an average weight of 166.8 to 195.4 g. In the control, it was 145.4 g, which was 12.8–25.6% less than in the experimental groups of fish. In all variants of the experiments and control, fish survival rate was 100%. The fish productivity of tanks was in the range of 6838.9–9588.9 g/m2. The highest productive parameters of bester were obtained in the variant where their main feed was supplemented with “Subalin” at the amount of 0.04% of the weight of the compound feed. Originality. The results of the use of probiotic “Subalin” as a supplement of the main feed of bester juveniles in the conditions of an industrial-type farm with the use of heated waste water from a power plant were studied. Practical value. The results are of interest for the development of sturgeon aquaculture technologies in the conditions of industrial-type farms, primarily with the use of secondary energy resources in thermal power generation.