The effect of replacing dietary fish oil with canola oil on fatty acid composition and expression of desaturase and elongase genes in Jade Tiger hybrid abalone

This study investigates the effect of graded substitution of dietary fish oil (FO) with canola oil (CO) on fatty acid composition and expression of Δ-6 desaturase and elongase 2 genes in the muscle of Jade Tiger hybrid abalone. The control diet contained 1.5% FO supplement (0% CO). Four other diets contained FO/CO in ratios of 3:1 (CO 25%), 1:1 (CO 50%), 1:3 (CO 75%) and 100% CO. The result demonstrated that abalone fed the diets supplemented with 25% and 50% CO showed similarly high levels of total omega-3 polyunsaturated fatty acid (n-3 PUFA), eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) (P < 0.05) as the 0% CO group. The highest levels of total PUFA and total monounsaturated fatty acids were found in the 100% CO group (P < 0.05). The results also showed that Δ-6 desaturase and elongase 2 gene expression was increased in a graded manner by increasing dietary CO (P < 0.05). It was concluded that replacement of FO by CO at the levels of 25–50% can improve the contents of health-benefiting EPA and DHA in abalone.