The aim of the work is to investigate the effect of compound feeds with different levels of protein on the growth of juveniles of the Australian red claw crayfish Cherax quadricarinatus. Used methods: To solve this problem, two experiments were carried out in the aquariums of aquaculture invertebrate department at VNIRO: the first was on juveniles weighing 0.017 ± 0.004 g and 0.87 ± 0.08 mm long; the second one was on juveniles weighing 0.31 ± 0.14 g and 23.7 ± 3.9 mm long. The duration of the experiments was 30 and 40 days, respectively. Feeding of juveniles was carried out with three variants of compound feed recipes with an estimated protein content of 25 %, 35 % and 45 %. The main part of the formulations consisted of components of plant origin. Tetra Wafer Mix food for fish and crustaceans (Germany) with a protein content of 45 % was used as a control. The duration of the experiments was 30 and 40 days, respectively. Feeding of juveniles was carried out with three variants of compound feed recipes with an estimated protein content of 25 %, 35 % and 45 %. The main part of the formulations consisted of components of plant origin. Tetra Wafer Mix food for fish and crustaceans (Germany) with a protein content of 45 % was used as a control. Newness: Development of a feed formulation for rearing juveniles of the Australian red claw crayfish in recirculating aquaculture systems (RAS). Results: These experiments showed that the growth rate of juvenile Australian red claw crayfish is directly dependent on the proportion of protein in the feed. It was established that the relative content of protein in the muscles of crayfish depends on its content in compound feed. An analysis of our own and published data indicates that feeds with protein content below 35 % cannot be recommended for growing of juveniles’ Australian red claw crayfish. Feeds with a protein content of 45 % are optimal for the growth of juveniles. It was established that the effectiveness of compound feeds depends not only on the protein content and energy value, but also on their taste attractiveness. Practical significance: The obtained results will be used in the development of mixed feed for juveniles Australian red claw crayfish.
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.
The purpose of the work: to investigate the provision of the domestic market with compound feeds for the cultivation of valuable fish species.Materials and methods: official data published by the Federal State Statistics Service on pricing and volumes of production and import of feed were used in the work. The methods of extrapolation and system analysis made it possible to determine the prospects for the production of fish feed in Russia and the barriers that need to be overcome.The results of the study. Proposals are given for the further development of the production of mixed fish feeds in the Russian Federation, taking into account the use of the scientific potential of branch science and state support measures. The forecast of the development of feed production until 2030 was made, on the basis of which the needs for compound feeds intended for the cultivation of high–value fish species — salmon, sturgeon, etc. were determined. Special attention is paid to the quality of feed as a result of improving the technology of their manufacture, the use of fishmeal, as well as concentrates of vegetable and animal origin. The market capacity has been determined in terms of the need for compound feeds for a long-term period, taking into account their possible export and import. At the same time, the main attention is paid to the production of domestic compound feeds, especially for the cultivation of high-value fish species currently purchased by import. The measures of state support aimed at the construction and modernization of enterprises for the production of feed for valuable fish species are proposed.The practical significance lies in the possibility of using the results of the study in order to strengthen the leading positions of domestic feed mills and ensure decent competition of domestic feed with imported analogues.
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