The effects of graded levels of dietary synthetic methionine (SMT), with yellow maize (YM) and cassava root (CVR) meal as energy sources in the diets of Claries gariepinus (mean weight, 24.02 ± 0.28g) were studied for 56 days. Two sets of five (5) experimental diets (D1, D2, D3, D4 and D5) were formulated at 38% crude protein and fortified with 1.50, 2.50, 3.50, 4.50, and 5.50% SMT/ 100g of diet respectively. YM or CVR was used as energy source in each of the 5 sets of diets while the controls were devoid of SMT (0.00%/100g). The SMT/YM diets elicited the deposition of significantly (P < 0.05) higher values of crude protein (CP), crude fibre (CF), ash (AS) and nitrogen free extract (NFB) in the fish than the SMT/CVR diets. Additionally, the growth performance of the fish showed that higher values of the weekly mean weight gain (WMWG) and the food conversion ratio (FCR) were obtained with fish fed the SMT/YM diets than with those fed the SMT/CVR diets. Although fishes fed the SMT/YM diets demonstrated better daily rate of growth (DRG) than those fed the SMT/CVR diets, the differences in growth were insignificant ( P > 0.05 ). This result is consistent with the report of other workers which stated that free methionine is poorly utilized by fish and it provides little or no benefit to catfish feeds. The results of this study also imply that YM is a better option as an energy source to enhance growth and nutrient deposition in fish than CVR meal.
Keywords : Clarias Gariepinus Synthetic Methionine, Yellow Maize, Cassava Root Meal, Energy Source.