Preliminary study to evaluate the efficacy of bambara groundnut (Vigna subterranea(L.) Verdc.) meal as the dietary carbohydrate source in nile tilapia, Oreochromis niloticus

Abstract

The present experiment was conducted to evaluate the effects of bambara groundnut meal (BGM) as the dietary carbohydrate source and as an alternative of dietary wheat flour in nile tilapia, Oreochromis niloticus. Results from the nutrient profile analysis of various carbohydrate ingredients showed, higher crude protein and lipid content in bambara groundnut meal followed by wheat flour, dextrin and corn starch. Whereas, dextrin was found to content lower amount of moisture compared to bambara groundnut meal, wheat flour and dextrin. Four isonitrogeonus and isocaloric diets were formulated to replace wheat flour using bambara groundnut meal at 0 (CON), 25 (BGM25), 50 (BGM50), and 100% (BGM100). Nile tilapia fish individual initial weight averaging 20±0.5 g (mean ± standard deviation) were fed one of the four experimental diets at 2~3% of body weight per day for eight weeks. At the end of the experiment, there were no significant differences in the average weight gain (WG) and specific growth rate (SGR) among the group of fish fed Control, BGM25 and BGM50 diets (P < 0.05). However, WG and SGR of fish fed BGM100 diet was significantly lower than that of fish fed BGM25 diet (P < 0.05). Crude protein and crude lipid content in the fish whole body proximate composition was not much affected by the BGM inclusion as a carbohydrate source. Therefore, the overall observations from the current experiment may suggest the potential of bambara groundnut meal as the carbohydrate ingredient in omnivorous fish diets. The optimum replacement level of wheat flour using bambara groundnut meal could be greater than 50 but less than 100% of diet in nile tilapia, Oreochromis niloticus.