EFFECT OF DIETARY VEGETABLE OILS WHEN FED TO GENETICALLY IMPROVED FARMED TILAPIA STRAIN OF NILE TILAPIA OREOCHROMIS NILOTICUS

An 8-week growth trial was conducted with GIFT (Genetic Improvement of Farmed Tilapia) tilapia to investigate the supplemented feed diets with different vegetable oil as substitutes for fish oil . Six diets were supplemented with 3% of either soybean oil (SO), palm oil (PO), cottonseed oil (CO), rapeseed oil (RO), phospholipid (SL), rapeseed oil (RO), 1:1:1:1:1 soybean oil-palm oil-cottonseed oil-rapeseed oil-phospholipid mixture (MIX). The results showed that: (1) The specific growth rate of CO group was significantly higher than that of the PO, CO, SL and MIX group (P0.05). The specific growth rate of SO group was significantly higher than that of the CO and PO group (P0.05). The feed conversion ratio of RO group was significantly lower than that of the PO, CO and SL group (P0.05), and had no significance with other groups (P0.05). The feed conversion ratio of SO group was significantly lower than that of the CO group (P0.05), and had no significance with other groups (P0.05); (2) Fatty acid composition of muscle in fish generally reflected the composition of the diet. The maximum correlation between muscle fatty acid composition and diet fatty acids composition was PO group, the minimal was CO group; (3) The activity of serum aspartate transaminase of PO group was significantly higher than that of the RO group (P0.05). The content of high density lipoprotein cholesterol of CO group was significantly higher than that of the RO and PO group (P0.05) and had no significance with other groups (P0.05). The content of low density lipoprotein cholesterol of CO group were significantly higher than that of the MIX group (P0.05) and had no significance with other groups (P0.05). The results suggested that rapeseed oil and soybean oil can be good lipid sources for the diet of the GIFT tilapia. Cottonseed oil will not improve the growth of the GIFT tilapia as good as rapeseed oil, palm oil, phospholipid oil and mixed oil.