Use of solid state fermented bambara nut meal as substitute of fishmeal in the diets of African catfishClarias gariepinus

Abstract

The use of plant proteins in substituting fishmeal (FM) is mitigated by several anti nutritional factors (ANF) like phytic acid, non starch polysaccharides and protease inhibitors. Fermentation of the plant ingredients can reduce the ANF and improve feed utilization and growth rate of fish. We produced five isonitrogenous and isocaloric diets using solid state fermented bambaranut meal (BNM). Fermented BNM substituted FM in diets of African catfish Clarias gariepinus. The FM: BNM inclusion percentages of the diets were, F1, 50:5; F2, 35:20; F3, 20:35; F4, 5:50 and F5, 0:56. There was a control feed labelled as F6. Feed F6 was a variant of F1 but with non fermented BNM. Fingerling African catfish C. gariepinus with average weight 5.14±0.05 g were fed with the diets for 56 days. Specific growth rate (SGR) was best for the catfish fed with F1, 7.82±0.25 % day-1, followed by those fed with F6, 7.35±0.24 % day-1. There were, however, no differences in SGR of F2, 7.26±0.18 % day-1 and F6. The food conversion ratio was lowest and best for the catfish fed with F1, 1.24±0.19 and F2 1.34±0.06. The growth and nutritional performance of fish fed with F2 were as good as F1 and cost-effective. Feeds made from fermented BNM had better FCR than those from raw BNM. Fermentation increased the protein and amino acid content of the BNM and the catfish gained more weight than from raw BNM. The effects of ANF seem to be highly reduced in solid-state fermented BNM thereby enhancing catfish growth.