The production costs of growing trout associated with feeding with intensive commercial growth is 50-60% of all production costs, therefore, it is necessary that fish feeding give a high economic effect. Currently, due to the high intensification of commodity aquaculture, the costs of the production of commodity fish are increasing, and, as a result, they increase its cost for the consumer. Combageum enterprises are forced to search for new highly effective components for the production of compound feeds that provide the body with the necessary nutritional and biologically active substances, as well as high-quality proteins and fats. To do this, plant components are introduced into the composition of compound feeds, among which plant concentrates occupy the main place - grain after various processing, vegetable oils, etc. In this work, the effectiveness of the use of cold-pressed linseed oil in combination with white lupine that has undergone barohydrothermal treatment (BGTO), as part of a compound feed for rainbow trout (Oncorhynchus mykiss), where linseed oil replaced 65% of fish oil, was investigated. The comparison was made with the formulations: without the inclusion of white lupine with 50% replacement of fish oil with rapeseed oil and with pure fish oil. The use of linseed oil in combination with white lupine after barohydralthermic treatment has led to an improvement in fish-breeding and biological indicators, and has also reduced the cost of compound feed. The conducted hematological studies allow us to assert that there is no negative effect of linseed oil and white lupin barohydralthermic treatment on the physiological state of rainbow trout. The structure of the intestinal tissue in all samples had no significant morphological changes. The conducted research allows us to conclude that it is possible to replace fish oil in the composition of production feeds for rainbow trout by up to 65%.

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