Lipid variations in tilapia (var. GIFT Oreochromis sp.) tissues due to dietary replacement of fish oil with camelina oil ( Camelina sativa )

Abstract

Dietary fish oil can potentially be replaced by camelina oil in aquafeeds since 18:3n-3 (α-linolenic acid: ALA) accounts for 35% of the fatty acids. To test the effect of camelina oil on fish lipid composition, a feeding trial with tilapia (var. GIFT Oreochromis sp.) was carried out. Four experimental diets were formulated, one containing only fish oil (TFO), two where fish oil was replaced by camelina at low (Low-CO) and medium (Med-CO) levels, and another made only with camelina oil (TCO). A commercial diet (COM) was used as a reference diet. At the end of an 8-week feeding trial, the liver, kidney, heart and brain were sampled. In terms of proportions across tissues, the liver showed the highest triacylglycerol and oleic acid content; the kidney was higher in arachidonic (ARA) and eicosapentaenoic acid (EPA); the heart had the highest total lipids, linoleic acid (LOA) and ALA, while the brain was higher in sterols, acetone-mobile polar lipids (AMPL), phospholipids and docosahexaenoic acid (DHA). In terms of concentration among diets within tissues, when comparing TFO vs TCO, the phospholipids and ARA increased in the kidney, while the phospholipids decreased in the heart and the DHA in the brain. The TCO diet significantly increased 20:1n-9 and ALA in all analysed tissues. As expected, the COM diet significantly increased concentrations of EPA, docosapentaenoic acid (n-3DPA) and DHA in all analysed tissues.