Productive feeding of rainbow trout: properties, effects on physiological state and interior indicators

Abstract

It is advisable to use secondary resources of the fish industry with high protein content as a raw material for the development of biologically complete feeds in aquaculture. The work uses standard and original research methods. A complex studies of the chemical composition, physico-chemical and microbiological quality indicators of the experimental feed proved its balance in amino acid composition. The degree of essential amino acids was 91.5 to 107.3%. The biological value of feed protein is 95.18%. It was proved that the amount of free ammonia released through the fish gills is directly proportional to the amount of feed eaten, inversely proportional to the feed coefficient and equal to 0.05. The pH value changed on the 42nd day from 7.6 to 7.7 but remained within the range of pH 6-9, which is optimal for the life support of fish. The absolute increase in the amount of individuals in the control group was 1.2% higher compared with the experimental one. At the same time, feed costs for the entire feeding period were 0.99. Fish survival was 98%. In both cases, bifidobacteria were isolated from the resistant microflora. Notably, the bifidobacteria titer was 3 lg units higher in the trout of the experimental group in comparison with the control group, which does not exceed permissible norms. Thus, the obtained feeding is not inferior in quality to the imported feeding. Therefore, it can be recommended for feeding rainbow trout grown in recirculating aquaculture systems.