Immunomodulatory activity of Aegle marmelos in freshwater fish (Catla catla) by non-specific protection.

Context: The production of fish is limited by infectious diseases; when a fish grows in an immunosuppressed condition, it becomes highly susceptible to disease.

Objective: The present research work investigates immunomodulatory action of Aegle marmelos (Linn.) Corr. Serr. (Rutaceae) in Catla catla Hamilton (Cyprinidae) for enhancing immune protection of the fish against bacterial infections.

Material And Methods: Doses of 0, 5, 10, 15, 20, 25 and 30 g aqueous plant leaf extract/kg feed were administered orally to the freshwater fish, Catla catla for a period of 30 days to investigate its efficiency to enhance the non-specific immune responses against the fish pathogen Pseudomonas aeruginosa (Schröter) Migula (Pseudomonadaceae).

Results And Discussion: The fish were challenged with pathogens through water medium for 30 days and the immunomodulatory effect of the Aegle marmelos was evaluated on the blood samples every 5 days until 15 days after infection. The results obtained from the study shows that the 25 g leaf extract/kg of feed was found to be competent to enhance optimum immune response. The effectiveness of the immunostimulant action was found to be best for the first 5 days after challenging with pathogen and subsequently, the immune response was found to decline in all the concentrations of plant extract.

Conclusion: The results of the study will be helpful for further investigation in the field to improve the immunocompetence of fish against bacterial pathogens.