Effect of different ratios of poly unsaturated fatty acids to mono unsaturated fatty acids of diets on growth indices and fatty acid profile of rainbow trout fry (Oncorhynchus mykiss)

AbstractThe purpose of this study was to investigate the effect of various ratios of dietary poly unsaturated fatty acids over mono unsaturated fatty acids (PUFA (C18) / MUFA) on growth indices and fatty acids profile of rainbow trout larvae at the onset of exogenous feeding. Four different diets contain various levels of PUFA (C18) / MUFA including 0.2, 0.5, 1 and 2 percent and at fixed level of highly unsaturated fatty acid) equaled to 6.5 percent were prepared. The larval density in each rearing tank was 100 fish and the experiment lasted for six weeks. At the end of the experiment, 30 fish were randomly collected from each treatment to evaluate the growth indices, biochemical and fatty acid composition of carcasses. Results showed that with increase in PUFA (C18) / MUFA levels from 0.5 to 1 and 2 percent the growth parameters decreased (P