Growth response of Heterobranchus longifilis fingerlings to Mucuna pruriens seed meal based diets
Laboratory studies on the growth responses of Heterobranchus longifilis fingerlings, mean weight 3.21 + 0.37g to Mucuna pruriens seed meals based diets were conducted for 70 days at the Federal College of Agriculture, Ishiagu in Ebonyi State, Nigeria. Mucuna pruriens seed meals were processed as either boiled or toasted and included at 0%, 6%, 12%, 18% and 24% in place of soybean in the entire diets. The experimental design was Randomized Complete Block Design (RCBD) with two processing methods of Mucuna seed meals (MSM) at five levels of inclusion, each with ten fingerlings replicated thrice and diets were fed at 5% fish body weight. The effects of processed MSM on Heterobranchus longifilis fingerlings (cumulative weight gain) were significant (P<0.05) from 4th to 8th week with boiled Mucuna seed meal (BMSM) being better than toasted Mucuna seed meal (TMSM) but did not differ significantly (P>0.05). Growth generally decreased with increase in MSM in the diets. However, Heterobranchus longifilis fingerlings fed 24% TMSM (zero soybean) recorded mean weight gain/day (MWG/D) of 0.170 ± 0.16g as against the control 0.197 ± 0.25g; specific growth rate (SGR) 2.07 ± 0.11against 2.31 ± 0.09; protein efficient ratio (PER) 1.11 ± 0.08 against 1.18 ± 0.15; crude protein of 59.46 ± 0.83% against 61.89 ± 1.9% ; increased FCR of 2.31 ± 0.17 against 2.03 + 0.06 ; and percentage mortality of 23.3 ± 20.8% against 10.0 ± 10%. The inclusion of 12% processed boiled Mucuna seed meal is therefore recommended for partial replacement of soybean meal to reduce the cost of fish production without adverse affect.
Key words: Mucuna seeds, protein source, processed, Heterobranchus longifilis, growth