Growth, hematology and liver health of African catfish (<i>Clarias gariepinus</i>, Burchell 1822) fed varying amounts of <i>Bacillus subtilis</i>

Abstract

The study assessed the effects of Bacillus subtilis (Bs) on the growth, hematology and liver health of Clarias gariepinus. The experiment  was conducted by supplementing a commercial fish feed with different doses of Bs thus 0 g/kg Bs, 10 g/kg Bs, 20 g/kg Bs and 30 g/kg Bs.  Fish of average weight 13.0 ± 0.22 g were put into four groups in triplicates and feed the prepared diets for 8 weeks. At the end of the  experimental period, growth parameters were evaluated and blood samples examined for effects of treatments on hematological  parameters and liver toxicity. The results showed that in terms of growth fish groups fed the Bacillus diets had significantly higher weight  gain, lower feed conversion ratio, higher viscerosomatic index and hepatosomatic index, and condition factor compared to the  control group. In the Bacillus group, 10 g/kg Bs showed a significant increase in hematological parameters compared with the other  groups. Lower amounts of aspartate aminotransferase and alanine transaminase were observed in the Bacillus fed fish compared to the  control group. The results suggest that dietary administration of Bacillus subtilis at 10 g/kg can effectively improve the growth and health   Clarias gariepinus.