RESUMEN
Ascorbic acid is one of the essential vitamins for normal physiological activities of any organism. The present study demonstrates an immunostimulatory effect of vitamin C on the humoral and cell mediated immunity of the bagrid catfish, Mystus gulio, determined using different bacterins of Aeromonas hydrophila. Humoral as well as cell mediated immune responses were elucidated in the vitamin supplemented, vaccinated and unvaccinated groups. The vitamin supplemented lipopolysaccharide (LPS) vaccinated group exhibited greater immune (both humoral and cell mediated) responses than its formalin killed (FK) and heat killed (HK) bacterin vaccinated counterparts. Nevertheless, in the challenge study, the relative percent survival (RPS) was found to be the same for both FK and LPS immunised vitamin treated groups while lower for the HK immunised vitamin treated group.