Authors : E.A. Fasakin , S.J.Davies and O.K. Gbadamosi
Abstract: The effect of supplemental crystalline L-lysine amino acid to improve the nutritive quality of maize gluten meal in diets of tilapia, Oreochromis niloticus was investigated in a 56-day experimental period using growth performance, efficiencies of nutrients utilization and whole-body composition as the response criteria. The trial comprised of eight isoproteic (32% crude protein) and isoenergetic (12% lipid) diets containing high grade protein (HGP) source from low temperature Norwegian fish meal (LT-94) as major provider of protein in diet 1, which served as a positive control or maize gluten meal as low grade protein (LGP) source in diets 2-8 with fish meal reduced by 65%. Diets 3-8 containing mostly of maize gluten protein were supplemented with crystalline L-lysine at the rate of 1.3, 1.6, 1.9, 2.2. 2.5 and 2.8% respectively while diet 2 without lysine supplementation served as the negative control. Diets were fed to triplicate groups of hatchery bred juvenile fish at 4% body weight twice daily at 10.00 and 16.00hrs in a freshwater recirculation system consisting of 24 fiber tanks with 15 fish randomly allotted to each tank. The results showed that reducing fish meal protein component in LGP diets (D2-D8) had negative effect on the growth performance and nutrient utilization of the fish. The fish fed on diet 2 (negative control) had the poorest growth, less efficient for feed consumption and nutrient utilization. However, increasing lysine supplementation in the diets (D3-D8) resulted in a progressive increase in growth performance and nutrient utilization indices. Optimum growth performance was however achieved for group of fish fed with diet containing 1.9% lysine supplementation but lower in values (p≥ 0.05) compared to the fish fed with fish meal based diet.
E.A. Fasakin , S.J.Davies and O.K. Gbadamosi , 2006. Dietary improvement and utilization efficiencies of maize gluten supplemented with lysine for Nile tilapia, Oreochromis niloticus. (L.). Journal of Fisheries International, 1: 27-32.