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

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  bambara nut  meal (BNM). Fermented BNM substituted FM in diets of African catfish Clarias gariepinus. The FM: BNM inclusion percentages of the diets were, F۱, ۵۰:۵; F۲, ۳۵:۲۰; F۳, ۲۰:۳۵; F۴, ۵:۵۰ and F۵, ۰:۵۶. There was a control feed labelled as F۶. Feed F۶ was a variant of F۱ but with non fermented BNM. Fingerling African catfish C. gariepinus with average weight ۵.۱۴±۰.۰۵ g were fed with the diets for ۵۶ days. Specific growth rate (SGR) was best for the catfish fed with F۱, ۷.۸۲±۰.۲۵ % day-۱, followed by those fed with F۶, ۷.۳۵±۰.۲۴ % day-۱. There were, however, no differences in SGR of F۲, ۷.۲۶±۰.۱۸ % day-۱ and F۶. The food conversion ratio was lowest and best for the catfish fed with F۱, ۱.۲۴±۰.۱۹ and F۲ ۱.۳۴±۰.۰۶. The growth and nutritional performance of fish fed with F۲ were as good as F۱ 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.  

Keywords:

Solid state fermentation , Fishmeal substitution , Food conversion ratio , Plant proteins , Specific growth rate