Effect of Dietary Polyherbal Mixture on Growth Performance, Haemato-Immunological Indices, Antioxidant Responses, and Intestinal Morphometry of African Catfish, Clarias gariepinus

Abstract

A 56-day feeding trial was conducted to evaluate the dietary effect of Nigeria polyherbal mixture (PHB) on growth, haemato-immune parameters, antioxidant enzyme activities, and intestinal morphometry of African catfish, Clarias gariepinus. Four diets were formulated with PHB powder at inclusion of 0 g/kg (control), 0.5 g/kg (PHB 0.5), 1.0 g/kg (PHB 1.0), and 2.0 g/kg (PHB 2.0) and fed to African catfish ( $6.32\pm 0.02\text{g}$ /fish, 15 fish/50 L tank) in triplicates. Fish fed PHB 2.0 recorded higher final weight, weight gain, and specific growth rate ( $p<0.05$ ) compared to the control. There were no statistical differences ( $p>0.05$ ) in feed conversion ratio and protein efficiency ratio among the dietary groups. The haematological profile indicates that the fish fed PHB-1.0 had higher Hb, RBCs count, and Hct, and blood performance ( $p<0.05$ ) compared to the control. ALT levels were found higher in the control and the lowest values recorded in PHB groups ( $p<0.05$ ); however, AST did not differ significantly among the groups ( $p>0.05$ ). The highest heterophil counts and respiratory burst activity were recorded in PHB-1.0 and PHB-0.5 and PHB-2.0, respectively, while a numerically improved total immunoglobulin value was recorded in PHB-0.5 compared to the control ( $p>0.05$ ). Antioxidant enzymes such as superoxide dismutase and catalase had a significant improvement in fish fed PHB-based diet compared to the control ( $p<0.05$ ), while glutathione peroxidase showed no statistical differences between the groups ( $p>0.05$ ). Intestinal morphometric measurements showed that the fish fed PHB-1.0 had the highest villus height, area of absorption, and villus height/cryptal depth ratio compared to the control. Muscle thickness increased ( $p<0.05$ ) with increasing PHB level with the highest value recorded PHB-2.0. In conclusion, dietary PHB could improve growth, blood profile, immunity, antioxidant enzyme capacity, and intestinal morphometry of African catfish without any significant alteration in the liver function enzymes.