Fatty Acid Composition and mRNA Expression of Fatty Acid Binding Protein Genes (fabp3 and fabp6) in Rainbow Trout Fed Camelina Seed Oil (Camelina sativa)-Based Diets

Abstract

Vegetable lipids such as camelina oil (Camelina sativa) are used as alternatives oil sources to fish oil in aquafeeds. In this study, we determined fatty acid-binding protein 3 (fabp3) and fatty acid-binding protein 6 (fabp6) gene expression and fatty acid composition in the liver and muscle tissue of rainbow trout fed different amounts of dietary camelina seed oil [100% (CO100), 67% (CO67), and 37% (CO33)]. Palmitic acid and oleic acid were identified as the most abundant saturated and monounsaturated fatty acids, respectively, in both tissues across all experimental groups. The highest levels of n-6 polyunsaturated fatty acid (Σn- 6 PUFA) were found in the first biopsy (15th day) taken from fish fed a diet of CO100, while the highest Σn–3 PUFA level was found in the third biopsy (45th day) taken from the same group. The FO100 (fish oil) diet was found to have the highest Σn-3 / n-6 ratio, as well as the highest levels of eicosapentaenoic acid and docosahexaenoic acid. In general, the fatty acid composition of the fish reflected that of their respective diets. The expression of fabp3 and fabp6 genes in the muscle of fish fed camelina seed oil were not significantly different from control group. However, fabp3 gene expression of liver of FO100 group was found to have significantly higher than CO67 and CO33. A difference in hepatic fabp6 gene expression was also noted in the FO100 group, but was not found to be statistically significant. Growth parameters and survival rate were not affected after the 45 days feeding trial. These results suggest that camelina seed oil can be used as an alternative to fish oil in rainbow trout diet.