EFFECTS OF DIETARY SUPPLEMENTATION OF AFRICAN WALNUT (Tetracarpidium conophorum) ON THE REPRODUCTIVE PERFORMANCE OF THE MALE AFRICAN CATFISH (Clarias gariepinus)

Abstract

The effects of dietary supplementation of Tetracarpidium conophorum seed powder was studied on male Clarias gariepinus broodstock weighing 302.39±1.80-305.89±0.10g through inclusion in five isonitrogeneous diets at the levels of 0, 50, 100, 150 and 200 mg/kg of feed denoted by control, TC1, TC2, TC3 and TC4 respectively. The experiment was carried out for a period of 56 days, the fish fed at 3% body weight per day. Reproductive performance indices (of %fertilization, %hatchability and %survival), and milt quality parameters (milt volume, milt counts, sperm motility, motility duration and percentage motility) were determined at the end of the feeding trial. The results showed Percentage fertilization, hatchability and survival were highest in fish fed TC4 (200 mg/kg).There were no significant difference (p>0.05) in weight of testes, gonadosomatic index and weight gain in fish in all the experimental diets. Milt volume (2.65 ± 0.21), number of spermatozoa per ml (53.95x104 ± 9.97), motility duration (58.00s ± 1.41) and percentage motility (92.50 ± 2.12), were highest in fish fed TC4 (200 mg/kg inclusion level of T. conophorum).The study revealed that dietary supplementation of T. conophorum seed powder at 100-200mg/kg of feed significantly increased milt quality of C. gariepinus. There was high spermatozoa density in the seminiferous lumen seen in the testicular histology of fish fed diets TC2, TC3 and TC4, signifying a better spermatogenetic activity of T. conophorum. Furthermore, the lumen of their seminiferous tubules showed evidences of hyper-spermatozoa formation in fish fed diets of 150 and 200 mg/kg T. conophorum. These findings suggested that T. conophorum possesses promising pro-fertility agents which could be exploited in fish seed production.