DIETARY VITAMIN K REQUIREMENT OF JUVENILE GIBEL CARP (CARASSIUS AURATUS GIBELIO)

A 10-week feeding experiment was conducted to determine vitamin K requirement of juvenile gibel carp (Carassius auratus gibelio). Purified diets with seven levels (0.13, 2.15, 3.25, 6.40, 12, 17.20 and 23.20 mg/kg diet) of supplemental vitamin K3 (menadione sodium bisulfite, MSB) were fed to C. gibelio (mean weight 2.170.01 g). Each diet was fed to triplicate groups of fish. The results showed that fish fed with the diet supplemented with 2.15 mg vitamin K/kg had significantly higher feeding rate (FR) than fish fed with diets supplemented with 12 mg vitamin K/kg (P0.05). Specific growth rate (SGR) increased with increasing dietary vitamin K levels and reached the highest value when dietary vitamin K content was 12 mg/kg (P0.05). Feed efficiency (FE) was the highest in fish fed with diet supplemented with 3.25 mg vitamin K/kg, intermediate with 2.15 mg vitamin K/kg supplemented diet and the lowest in the control group (P0.05). FE reached the highest value when the dietary vitamin K content was 12 mg/kg (P0.05) and showed a linear correlation with SGR (SGR=0.01 FE+0.95, R2=0.95). The number of red corpuscles (RBC) in blood increased significantly with increasing dietary vitamin K level (P0.05) and reached the plateau at 6.40 mg vitamin K/kg. The Hb content, Hct and serum Ca content followed the same trend as RBC and were the lowest in gibel carp fed with diet without vitamin K supplementation (P0.05). HSI, CF and whole body composition were not affected by dietary vitamin K level (P0.05). Based on the broken-line regression between FE or RBC and dietary vitamin K level, we concluded that the adequate supplemental dietary vitamin K content for gibel carp was 3.736.72 mg/kg.