Effect of temperature on dietary vitamin C requirement and lipid in common carp.

We investigated the effect of temperature on the requirement of vitamin C in common carp. Small carp (0.70 g) was separately cultured at 25 and 35 degrees C, respectively, and fed diet with or without supplement of 2000 ppm vitamin C. The fish increased weight gain and had smaller feed conversion rate at 25 degrees C than at 35 degrees C, with vitamin C-supplement and subsequently, without vitamin C-supplement. The level of vitamin C in the hepatopancreas and muscle, the ratio of hydroxyproline/proline and the level of collagen in the bone and skin were higher both at 25 degrees C than at 35 degrees C, with vitamin C-supplement and then without vitamin C-supplement. Judging from these results, the carp required vitamin C-supplement when cultured at high temperature. The level of thiobarbituric acid reactive-substance (TBARS) in the hepatopancreas and muscle of fish was higher at 35 degrees C than at 25 degrees C, without vitamin C-supplement and then with vitamin C-supplement. The level of glutathione was contrary to that of TBARS. Triglycerides and the ratio of polyunsaturated fatty acid (PUFA) in hepatopancreas and muscle of fish were higher at 25 degrees C than at 35 degrees C, and without vitamin C-supplement than with vitamin C-supplement. It is concluded that temperature and vitamin C influence lipid composition and peroxidation in the hepatopancreas and muscle of common carp.