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 26th 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.
Keywords: Clarias gariepinus, Ascorbic acid, diets, Health