Effect of dietary lipids on fatty acid composition and lipid peroxidation in sarcoplasmic reticulum of hybrid tilapia, Oreochromis niloticus × O. aureus.
Hybrid (O. niloticus × O. aureus) tilapia, mean body weight 3 g, were assigned to 15 plastic tanks, 40 per tank. Five diets containing no lipids or different sources of lipids, lard, soya oil, menhaden fish oil and methyl ester of n-3 HUFA (highly unsaturated fatty acids) were assigned to the tanks for 10 weeks. Enzymic lipid peroxidation in the sarcoplasmic reticulum (SR) of these fish was studied. There was no difference in survival rates among test groups. Compared with fish supplied with dietary lipids, fish fed on the control diet with trace lipids (0.02%) had low final body weights and muscle lipids. Specific growth rates and weight gains of fish fed on soyabean oil and fish oil were higher than the other groups (P<0.05). Fatty acid composition of muscle and SR reflected the fatty acid compositions of dietary lipids. The thiobarbituric acid reactive substances produced by Fe-catalysed NADH-dependent lipid peroxidation were different (P<0.05) among SR isolated from fish fed on different dietary lipids. Lipid peroxidation activity of the HUFA group was the highest, followed by fish oil, soyabean oil, lard and the control group.