The influence of a dietary lipid source on growth, muscle fatty acid composition and erythrocyte osmotic fragility of hybrid tilapia

An 8-week feeding trial was conducted to determine the effects of various dietary lipids on the growth, tissue proximate composition, muscle fatty acid composition and erythrocyte osmotic fragility of red hybrid tilapia, Oreochromis sp. Five isonitrogenous and isoenergetic semipurified diets were supplemented with 10% of either cod liver oil (CLO), sunflower oil (SFO), crude palm oil (CPO), crude palm kernel oil (CPKO), or a combination of 5% CLO with 5% palm fatty acid distillates (PFAD), respectively. There were no significant effects (P > 0.05) of diet on growth but fish fed the CLO diet showed a significantly (P < 0.05) poorer feed efficiency ratio compared to fish fed the CPO diet. Lipid deposition in fish muscle was mostly similar among fish fed the various diets but bone ash was significantly higher in fish fed the CPO and CPKO diets. Muscle lipids of fish fed palm oil-based diets did not increase in saturated fatty acids content but showed significantly lower polyunsaturated fatty acid (PUFA) concentrations compared to fish fed the CLO diet. The concentrations of individual PUFA in muscle lipids were strongly influenced by dietary PUFA concentrations. Dietary lipids did not markedly affect the structural integrity of erythrocyte membranes but the erythrocytes of tilapia fed the CPO diet were slightly more resistant to osmotic lysis. It was concluded that palm oil products, especially CPO, could be successfully used in the diet of hybrid tilapia based on its availability, cheaper costs and its potential ability to enhance oxidative stability due to its low PUFA content and high natural concentrations of antioxidants.