A major factor limiting fish production is regular outbreak of diseases. This usually constitute substantial monetary loss, either directly or indirectly by increasing production cost through investment lost to dead fish; cost incurred on treatment and slowed fish growth during period of recovery of diseased fish (Mzula et al., 2021). The use of antibiotics which is the conventional means of treating diseased fish is being discouraged because of its negative impacts such as the potential development of antibiotic resistant bacteria, suppression of immune system , bio accumulation of toxic residues and their bio-magnification up the food chain (Vignesh et al., 2011). The significance of other more sustainable health management strategies including the use of medicinal plant has thus been better realized.
The present study investigated the effects of varying dietary levels of Acalypha wilkesiana leaf extract on growth, haemato -immunological and antioxidant enzyme activities of Clarias gariepinus fingerlings. 150 fingerlings (6.07 ± 0.02g) of Clarias gariepinus were randomly stocked in fifteen tanks and fed isonitrogenous (40% crude protein) diets containing 0% (diet 1), 0.25% (diet 2), 0.5% (diet 3), 0.75% (diet 4) and 1% (diet 5) of A. wilkesiana leaf extract for sixty three days. At the end of the experiment, diet 3 significantly (p < 0.05) increased weight gain (34.66 ± 2.76g) and the specific growth rate (3.02 ± 0.11%/day) relative to the control group (Table 1) . Feed conversion ratio and protein efficiency ratio were however similar (p > 0.05) in the control and other treatment groups. Significantly (p < 0.05) lower white blood cell count was recorded in the group fed diet 5 when compared with those of diets 1-3. The serum aspartic aminotransferase was significantly (p < 0.05) higher in the group reared on diet 3 when compared to the control group. Serum total protein and its fractions (albumin and globulin) were not significantly (p > 0.05 ) influenced by dietary treatment. The respiratory burst activity and total immunoglobulin ranged between 0.73 ± 0.04 – 0.80 ± 0.05 and 0.09 ± 0.01 – 0.13 ± 0.01 g/dL respectively and did not differ significantly (p > 0.05) across dietary groups. Serum superoxide dismutase (SOD) and reduced glutathione (GSH) significantly (p < 0.05) increased in all treatment groups compared to control, while there were no significant (p > 0.05) difference in serum malondialdehyde (MDA) . It was concluded that addition of 0.5% A. wilkesiana leaf extract in the diets of Clarias gariepinus fingerlings can improve their growth and health status.