Effect of dietary vitamin C on the disease susceptibility and inflammatory response of mrigal, Cirrhinus mrigala (Hamilton) to experimental infection of Aeromonas hydrophila

Two groups of 3-day-old hatchlings of Cirrhinus mrigala were fed with vitamin C supplemented (at 1000 mg vitamin C/kg diet) and non-supplemented practical diet for a period of 4 months. At the end of the feeding period, fishes were examined for their disease susceptibility and inflammatory response to a virulent strain of Aeromonas hydrophila. Mortality curves were clearly distinct and the vitamin C non-supplemented (VNS) group showed significantly higher mortality rates compared to the vitamin C supplemented (VS) group. While studying the inflammatory response to A. hydrophila, it was found that in the VS group, the infiltration of phagocytic cells was quicker with very limited lesion development at the injection site and there was complete resolution by day 9 post-injection. In the VNS group, the bacterium was able to produce necrotic lesions clinically and histologically typical of a disease condition.