LAUSR

Abstract The development of aquaculture in Nigeria is constrained by the inadequate supply of high quality of fingerlings of African catfish (Clarias gariepinus). There are conflicting reports on the reproductive efficacy of Vernonia amygdalina when compared with the synthetic hormone Ovaprim (OV) and Pituitary Extract (PE) on C. gariepinus. The histopathology of select organs in catfish treated with generic Ovaprim (OV), Pituitary Extract (CPE), and aqueous extract of Vernonia amygdalina (VAE) were evaluated. Sixteen female C. gariepinus (average weight of 1 kg) wereevenly and randomly distributed to four groups. Fish in groups A, B, C, and D were injected intramuscularly with aqueous solutions of OV (0.5 mL/kg), PE (5 mg/kg), VAE (10 mg/kg), and distilled water (DW; 0.5 ml), respectively. Histological examinations of the ovary, liver, kidney, and spleen were carried out. Histopathology revealed that OV- and PE-treated groups showed synchronous and synchronous ovarian development, vacuolar change of hepatocytes, thinning of hepatic cords, reduced renal haemopoietic compartments, tubular degeneration and necrosis, and decrease in splenic periarteriolar lymphoid sheaths (PALS). VAE-treated groups had asynchronous ovarian development with atretic ovarian follicles, widespread vacuolar change of hepatocytes, intact renal tubular and hemopoietic compartments, and preponderance of large and coalescing splenic PALS. We conclude that VAE is an ineffective spawning agent, especially when compared with OV and PE, as VAE could not induce synchronous gonadal development. However, VAE may have immunopotentiating, nephroprotective, and haemopoietic properties.