Fish oil replacement with vegetable oils in compound feeds for rainbow trout

Abstract

The aim of the work was to study the effect of compound feeds with full or partial replacement of fish oil with vegetable oils on the composition of tissues and growth perfomance of rainbow trout. Method of chemical analyses was used for the estimation of nutritional value of the feed. To determine the fatty acid composition of the total lipids of feed and muscle tissue of trout, methyl esters of fatty acids were analyzed on a Crystal 5000.2 chromatograph. To assess the effect of compound feeds on fish, a number of fish-breeding and biological indicators were determined. The novelty of the study is associated with modeling the optimal ratio of fish oil, rapeseed and soybean oils in fish diets. As a result of the research, it was found that the highest growth rates and survival at lower feed costs were found in fish grown on diet without replacing fish oil and diet with a mixture of fish oil, rapeseed and soybean oils in a ratio of 4:6:5. Replacing fish oil with vegetable oils in feed recipes did not adversely affect the chemical composition of fish muscle tissue. Due to the elongation and desaturation processes occurring in the tissues of rainbow trout, the inclusion of rapeseed and soybean oils in the compound feed did not lead to a decrease in the amount of eicosapentaenoic and docosahexaenoic fatty acids. The practical significance of the work lies in obtaining new diets for compound feeds for valuable fish species, providing opportunities for effective cultivation of rainbow trout with specified quality characteristics.