The effect of the replacement of fish oil with animal fats on the growth performance, survival and fatty acid profile of rainbow trout juveniles, Oncorhynchus mykiss; [yavru gökkuşaǧı alabalıǧı oncorhynchus mykiss yemlerinde balık yaǧının hayvansal yaǧlarla i̇kamesinin büyüme performansı, yaşama oranı ve yaǧ asidi profili üzerinde etkisi]

A six-week feeding trial was conducted to investigate the suitability of animal oils as total replacement for cod liver oil (CO) in rainbow trout juvenile feeds. Four experimental diets were formulated: CO, goose fat, sheep tail fat and beef tallow. The final weights of fish were not significantly different among dietary treatments. Survival rate recorded during the experimental period was 100% for all treatment groups. Highly significant relationships between oil source and whole body fatty acid composition were determined in all treatment groups. The preliminary saturated fatty acid and monounsaturated fatty acid were 16:0 and 18:1 n-9, respectively. The CO diet contained highest levels of total n-3 polyunsaturated fatty acid, especially eicosapentaenoic acid and docosahexaenoic acid. The n-3/n-6 ratio of in fish fed CO diet was also quite higher compared to that in fish fed the other diets. In conclusion, the results of this study show that total substitution of fish oil with animal fats impairs nutritional value of the fatty acid composition of rainbow trout juveniles. © Published by Central Fisheries Research Institute (CFRI)Trabzon, Turkey.