| Abstract: | The disease resistance and humoral immunomodulatory effects of vitamin C administered orally to grouper, Epinephelus awoara maintained on a frozen fish diet supplemented with vitamin C at 500, 1000, 1500 and 2000 mg/kg were investigated. After 20 weeks, the growth rates of the groups with high level of vitamin C apparently increased. The untreated fish had symptoms of vitamin C deficiency. The endogenous liver tissue vitamin C levels were found to reflect well the dietary treatments. After intraperitoneal injection or bath challenge with a virulent strain of Vibrio vulnificus , fish fed with high level vitamin C showed significantly higher survival rate compared with the normal control group. Vaccination with formalin inactivated V. vulnificus significantly enhanced the specific antibody production in fish treated with vitamin C, and completely protected from strong bacterial challenge the groups fed on fish with vitamin C 1500 and 2000 mg/kg diet. |
