Dose dependence specific and non-specific immune responses of Indian major carp (L. rohita Ham) to intraperitoneal injection of formalin killed Aeromonas hydrophila whole cell vaccine.

Specific and non-specific immune response to different doses of formalin killed whole cell vaccine of Aeromonas hydrophila to Indian major carp (Labeo rohita) was evaluated in laboratory condition. Three different doses (10(5) CFU/ml, 10(7) CFU/ml, 10(10) CFU/ml) were administered (0.2 ml/fish) intraperitoneally for 1 month. Among the three doses, 10(10) CFU/ml elicited the highest antibody and protective response followed by the doses 10(7) CFU/ml and 10(5) CFU/ml. Upon challenge with the virulent strain of A. hydrophila, the relative percentage of survival was recorded up to 80% at highest dose of 10(10) CFU/ml. The non-specific responses, similar to the specific immune responses were also maximum at highest dose of 10(10) CFU/ml. Similar to the specific immune responses, the non-specific responses were maximum at highest dose of 10(10) CFU/ml. Therefore, dose containing 10(10) CFU/ml of formalin killed cells was found to be the most effective dose for vaccination which increased the immunity in Indian major carp (Labeo rohita) to a larger extent.