Increase of resistance and improvement of adaptation and compensatory mechanisms of the body of juvenile fish under conditions of multitrophic aquaculture.

Abstract

The relevance of the study is conditioned by the trend in the development of organic aquaculture with the production of environmentally safe products. The purpose of the study was to determine and compare the effectiveness of the introduction of feed factors of different origins in feeding and rearing rainbow trout in the early stages of ontogenesis. The study was based on theoretical (analysis, synthesis, comparison, modelling), experimental, and laboratory methods adopted in fisheries, physicochemical studies. The results show an increase in the resistance and overall viability of the body of young trout, an improvement in the morpho-functional parameters of the blood, and activation of metabolic processes in the experimental groups 1 and 2. However, higher parameters were obtained in experimental group 2 in relation to other study groups. The average body weight of fish exceeded the parameters in experimental group 1 (by 11.7%, p < 0.01) and experimental group 2 (by 19.5%, p < 0.001) of the control group. The total number of red blood cells in experimental group 1 exceeded the values in the control group by 10.6% (p < 0.01) and in experimental group 2 by 15.3% (p < 0.001). In experimental group 1, the total protein content exceeded the value by 14.8%, in experimental group 2 – by 22.2% (p < 0.01) compared to the control group. The creatinine content in the blood of fish in experimental group 1 exceeded the values (by 9.7%) and in experimental group 2 (by 17.6%, p < 0.05) of the control group. The biochemical composition of the muscle part of trout was higher and better in terms of nutritional characteristics in experimental group 1 and 2 compared to the control group. The proposed method of feeding by two methods (experimental groups 1 and 2) promotes activation of fish growth rates in two experimental groups. The practical significance of the study is to help improve qualitative and quantitative parameters, in particular, the biochemical composition of the muscle part in experimental groups 1 and 2 compared to control values against the background of increased growth rates