Abstract
The article presents the results of a study on the effects of the feed additive “Eco Feed”, produced from food waste, on the indicators of natural resistance and the morphological condition of the internal organs of rainbow trout (Oncorhynchus mykiss). The experiment was conducted for 90 days at the facilities of TENGRYFISH LLP. Three groups of rainbow trout, each consisting of 50 individuals, were formed for the study. The control group received a standard diet, while the experimental groups were additionally supplemented with the “Eco Feed” feed additive at levels of 3% and 5% of the basal feed weight. The results demonstrated that the use of the feed additive contributed to the improvement of hematological blood parameters. The experimental groups showed increased erythrocyte counts, hemoglobin concentration, and hematocrit levels compared with the control group. Biochemical analyses revealed an increase in total serum protein concentration accompanied by a decrease in alanine aminotransferase and aspartate aminotransferase activities. Indicators of natural resistance also exhibited positive dynamics: lysozyme activity increased to 32.4%, while the phagocytic activity of leukocytes reached 44.8%. Histological examination of the liver, kidneys, stomach, intestine, myocardium, and skeletal muscles revealed no signs of inflammation, necrosis, or pronounced degenerative changes. The morphological structure of the examined organs corresponded to physiological norms, indicating the absence of any toxic effects of the feed additive on the fish organism. The obtained results confirm the safety of the “Eco Feed” feed additive for rainbow trout and demonstrate its positive effect on the indicators of natural resistance.