REPLACEMENT VALUE OF JACKBEAN MEAL FOR SOYBEAN MEAL IN NILE TILAPIA. {Oreochromis niloticus) DIETS

Abstract

Replacement value of jackbean meal for soybean meal as a dietary component for Tilapia, Oreochromis niloticus was evaluated. Four isonitrogenous and isocaloric (30% crude protein) diets were fed to Oreochromis niloticus fingerlings (6.36 ± 0.07g) in a glass tank for70days. The soybean meal in the diet was replaced at the rate or 20, 30 and 40% to serve as test-diet D20, D30 and D40 respectively while a diet without jackbean meal served as control (CTR). There were no significant differences (P > 0.05) in specific growth rate, weight gain, % weight gain and protein efficiency ratio between the fish fed control diet and diet D20 . Diet D40 differed significantly (P < 0.05) from diet CTR, D20 and D30. However, there was no significant difference (P > 0.05) in the protein efficiency between the fish fed control diet and test diets. Significant (P < 0.05) variation occurred in nutrient (Protein) digestibility of fish fed control diets and test diets. However, there were no significant differences in lipid and organic matter digestibility of fish fed control diets and test diets. The profitability of feeding fish with the test diet was positive (as attested to by profit index). The incidence costs of producing 1kg of fish with the control diet and test diets 020, D30 and D40 showed that it was cheaper to produce 1kg of fish with diets D20 and D30. The results showed that it is technically feasible, biologically and economically effective to replace soybean meal up to 30% with jackbean in the practical diets of Oreochromis niloticus .