JO Oyedokun, OA Ogunwole, OA Oyelese
Effects of supplementing roasted soyabean based diet with the first two limiting amino acid (L-lysine and DL-methionine) on growth performance and proximate composition of Clarias gariepinus (C. gariepinus) were investigated in this study. Juvenile fish (n=360), weighing 19.60±0.10g were randomly allocated to six diets containing varied supplemental combinations of lysine+DL-methionine (g/100g) in the formulated basal roasted soyabean based diets (RSBD) ; R1 (without supplemental lysine and DL-methionine), R2 (0+1), R3 (0.25+0.75), R4 (0.5+0.5), R5 (0.75+0.25), R6 (1+0) supplemental L-lysine+DL-methionine, respectively. The fish were fed to satiation with the diets for 12 weeks. Each treatment was in triplicate. Results revealed that the diets had no significant influence (P>0.05) on fish final weight and feed conversion ratio. Gross protein retention of fish on R3 (1.01±0.04) and R5 (0.97±0.04) were similar. The crude protein composition of C. gariepinus whole body on R5 (70.03±1.60) and R3 (68.39±1.46) were not significantly difference (p>0.05) but significantly higher than other diets. Supplemental amino acid significantly increased the methionine composition (P<0.05) with the higher value of 2.42±0.04 in fish on R4 and least value of 2.12±0.02 in those on R2. C. gariepinus on R5 (10.69±0.01) had a significantly higher (P<0.05) lysine value and least in those in control (6.94±0.04) diet. Regression of crude protein of fish whole body and supplemental lysine and methionine were both quadratic with the optimum dietary inclusion levels 0.6g/100g (R2= 0.79) and 0.4g/100g (R2=0.76), respectively. In conclusion, dietary supplement of lysine and methionine in roasted soyabean based diets had no impact on growth performance but enhanced the body composition of C. gariepinus.
