Title-Combinatory Effects of Diets with Three Protein Levels and Two Fat Levels on Growth Performance and Fillet Composition of Cage Cultured Genetically Improved Farmed Tilapia (GIFT)

Effect six diets having two lipid levels and three crude levels on growth and fillet composition of Genetically Improved Farmed Tilapia (GIFT) reared cages was evaluated. Diets having Crude Protein levels (CP) 26%, 30% and 36% and Crude Fat levels (CF) (7% and 12%) were formulated. Experiment was set up according 3 X 2 factorial designs. GIFT fingerlings (2.94 ± 1.47g) were stocked at a density 75 /m-3 net cages each having a water volume 2 m3. Fish quadruplicated treatments were fed six diets 150 days. Fish fed with 36% CP diets had significantly different (P≤0.05) values all growth indices; Final Mean Weight, Specific Growth Rate, Feed Conversion Ratio and Net Yield while no such difference found between 26% CP and 30% CP diets for the same growth indices. Increasing fat level from 7% to 12% had no significant effect on growth performances in GIFT any level diet. Diets having higher CF level (12%) had significantly affected (P≤0.05) the, CF fillets while no sparing seen fillets. There was no marked difference content fish fillets fed 30% and 36% CP diets. Findings reveal that increased fat levels do not contribute protein sparing and the diet having 36% CP and 7% CF is suitable the grow out phase and 36/12 fattening phase GIFT reared cages.