Abstract:

Substitution of fishmeal with plant protein is trending but there had been no study of its effects on catfish gut microbial communities. We made Five isonitrogenous (44.29±0.45%) and isoenergetic (2747.24±0.09 kcal) diets labelled as feed 1 (F1) to feed 5 (F5). The feeds varied in composition of fishmeal (FM) with bambaranut meal (BNM), as: F1, 65:0, F2, 45:5, F3, 25:25, F4, 5:45, and F5, 0:65. There was a control diet F6. The diets were fed to Clarias gariepinus distributed into three replicate aquaria at 15 fish per aquarium. Feed 4 (F4) had the best specific growth rate (SGR, 7.03±0.03% day-1), which was better than F3, with SGR, 6.77±0.08% day-1 and 65% fishmeal diet F1, with SGR 6.67±0.06% day-1 (P<0.05). F2 and F4 fed catfish were used to analyze gut microbiota. The F2 catfish foregut had microbiota comprised Gram –ve rod Citrobacter freundii, Gram +ve cocci Staphylococcus aureus spp and Gram +ve straight rod Bacillus spp, Citrobacter freundii was the dominant. The F4 catfish had foregut dominated by Gram –ve rod Citrobacter freundii and Gram +ve cocci Staphylococcus aureus aureus. The midgut of catfish fed with F2 had microbiota dominated by Citrobacter freundii and Bacillus subtilis. The performance of catfish on diets seems to be enhanced by the gut microbiota. Most digestion takes place in midgut and the consortium of bacteria dominant in African catfish midgut are known to be enzyme producing and celluloselytic and seems to be reason for African catfish known ability to utilize high carbohydrate diets.

Keywords: