Comparative analysis of the biochemical composition of rainbow trout blood serum under different feeding diets

Rational and efficient feeding of aquaculture objects is one of the foundations of production in highly productive fish farming. The aim of the study was to compare the composition of production compound feeds for aquaculture objects and to study the effect of compound feeds on the biochemical parameters of the blood serum of rainbow trout. To achieve the aim of the study, 10 groups of rainbow trout (Parasalmo mykiss (Walbaum, 1792) of the "Rofor" breed) grown in production conditions of cage farms in Karelia were selected. Alanine transferase, aspartate aminotransferase, alkaline phosphatase, total protein, albumins, creatinine, urea, glucose, total bilirubin and total cholesterol were determined in the blood serum of the studied individuals. The obtained result has an important practical significance since with excessive intake of carbohydrates these fish develop liver glycogen overload syndrome due to insufficient insulin production. Therefore, the optimal carbohydrate content for them is 20-30%, including 5-6% fiber. In this case, monosaccharides are used better - glucose, fructose, mannose, somewhat worse - disaccharides and starch, and cellulose is broken down only by 10-20% of the consumed. In addition, it is necessary to take into account that trout, as a cold-loving fish, cannot use carbohydrates in the same volume as heat-loving objects of aquaculture, therefore, in order to save protein, which can be used for energy purposes, it is necessary to additionally introduce fats into their diets. However, in the studied compound feeds this component did not meet the GOST standards. The results of the conducted research can be used to optimize the composition of production feed for rainbow trout and to register background ichthyohematological criteria for the quality of keeping highly productive aquaculture species.