Seasonal Variations in Deposition, of Fat in the Body of Rainbow Trout Oncorhynchus Mykiss (Walbaum 1792) and Its Effect on Yield and Quality of Meat in Cages at Commercial Breeding Farm

摘要

The aim of the experiment was to determine the effects of seasonal changes in the degree of fat deposition in various parts of the body and its impact on yield VSI (Viscero Somatic Index) of rainbow trout Oncorhynchus mykiss (Walbaum 1792), under the same conditions of feeding in cage farming systems of commercial fish farms. The task was to identify what is and what impact seasonal variation and environment on yield and quality of the meat of rainbow trout, which is fed with same nutrients to achieve a certain weight. As a basic experimental material has been used rainbow trout produced for the Bosnian and foreign markets of varying body weight: First group of fish between 150 ± 5 g, group II 200 ± 5 g and III group 250 ± 5 g. The same is provided from the local fish farm Salakovac on the Neretva River. A total of 180 fish samples were analyzed. This test showed there were highly significant statistical differences in the content of: fat (0.000), moisture (0.000), and protein (0.000) relative to the weight of the samples. Gathering data confirmed there were statistically significant differences between the seasons March-November in fat content (0.019), and November-December (0.033). At the same time proteins showed statistically significant differences only in relation to season of March-August (0,001). The results of analysis of the value of Viscero Somatic Index (VSI) showed very highly significant statistical difference in relation to season (0,000).