Vitamin C is ail essential micro-nutrient for most fish and plays an important role in immunity and physiology. The deficiency of dietary vitamin C can result in the damage on fish. The study on the deficiency symptom and the sensitive indicator of vitamin C could provide useful information for fish feed industry. This experiment was conducted to investigate the effects of dietary Vitamin C levels oil growth performance, immune and physiological responses in Chinese long-snout catfish (Leiocassis longirostris Gunther), which is ail high value aquaculture fish in China. Three practical diets containing 38, 364 and 630mg/kg vitamin C were fed to Chinese longsnout catfish (23.19 +/- 0.58g) for 8 months. Vitamin C was used in the form of L-ascorbyl-2-polyphosphate. The results indicated that the Chinese longsnout catfish in 38mg/kg vitamin C groups showed typical vitamin C deficiency symptom : skin color turning darker, spinal deformities and scoliosis, erosion of fins, anaemia. SGR and the serum lysozyme activities decreased significantly (p < 0.05), the hepatic SOD activities and MDA contents increased significantly (p < 0.05). There was no significant difference in serum cortisol concentrations (p > 0.05). The inductive HSP70 in liver was not detected by western-blotting in all groups. In conclusion, serum cortisol and hepatic HSP70 were not the sensitive indicators for vitamin C deficiency symptom, but the serum lysozyme, hepatic SOD activity, hepatic MDA content and the haematological index ( red blood cell number and hemoglobin content) were the more reliable makers to indicate the physiological status in Chinese longsnout catfish.
Liu Hai-Yan (firstname.lastname@example.org) ; Lei Wu; Zhu Xiao-Ming; Yang Yun-Xia; Han Dong; Xue Min; Xie Shou-Qi (email@example.com).EFFECTS OF DIFFERENT DIETARY VITAMIN C LEVELS ON CHINESE LONGSNOUT CATFISH (LEIOCASSIS LONGIROSTRIS GUNTHER),Acta Hydrobiologica Sinica,2009,33(4):682-689