Effects of Supplemental Vitamin C (Ascorbic Acid) on the Growth and Health of African Catfish Clarias gariepinus

Four different diets each containing 37.4% crude protein were formulated from locally available feed materials to contain 0 (control), 23, 46 and 92 mg/Kg supplemental Ascorbic acid (AA) respectively. Catfish with average weight of 2 - 6g were stocked and fed twice daily to satiation initially with Coppens fish feed for the first 9 weeks, sorted by weight equality into four ponds at different times; and further fed with the experimental diet till the 26^th week. Growth performance was tested using data from length and weight measurements of the fish. Weight gain was generally significantly (P<0.02) higher in groups fed 92 mg/Kg AA and 46 mg/Kg AA than those fed with 0 mg/Kg Ascorbic acid and 23 mg/Kg AA, but those fed 0 mg/Kg AA showed higher mean weight gain (527.86g) than those fed 23mg/kg AA (257.74g). Protein efficiency ratio was higher in the group fed 0mg/kg AA than the other groups. Liver AA was significantly higher (P<0.05) in groups fed 92 mg/kg AA. The group which received 0 mg/Kg AA and 23 mg/Kg AA in their diets manifested deficiency signs such as nodules on neck, skin lesions, head lesions and very visible sutures, but those fed 46 mg/Kg AA and 92 mg/Kg AA had a healthy body appearance. Evidence from this study shows that growth or weight gain of catfish is not solely dependent on supplemental vitamin C availability; but low amounts or absence of supplemental vitamin C bring about poor health.