Requirement of African catfish (Clarias gariepiuus) larvae for vitamin C administered in dry feed

摘要

The aim of the paper was to determine requirements of African catfish (Clarias gariepinus, Burchell 1822) larvae for vitamin C, with starter feed as the only feed given to fish. The fish received five feeds differing in vitamin C content. The experimental groups were calculated as 0, 50, 100, 500 and 5 000 mg of vitamin C per 1 kg of feed (exact amounts of vitamin measured by HPLC were slightly different). The best growth was achieved by fish receiving about 500 mg of vitamin C (SGR = 21.01, P < 0.05, group 4) while the slowest growth (SGR = 18.32, P < 0.05) was detected in fish fed the diet with no addition of vitamin C (group 1). The same groups had the lowest and the highest feed conversion rate (FCR = 0.9 and 2.3, respectively, P < 0.05) and the ascorbate content in the bodies 9.62 mug/g after 28 days in group 1, 167.6 mug/g in group 4 (P < 0.05). The shortest time of complete larval development measured as the time of the air-breathing beginning was found in, fish of groups 4 and 5 (308 and 280 Ddegrees, respectively) while fish from group 1 receiving the diet deficient in vitamin C finished their development in 607 Ddegrees.