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

AbstractContext: The production of fish is limited by infectious diseases; when a fish grows in an immunosuppressedcondition, 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 bacterialinfections.Material and methods: Doses of 0, 5, 10, 15, 20, 25 and 30 g aqueous plant leaf extract/kg feed were administeredorally to the freshwater fish, Catla catla for a period of 30 days to investigate its efficiency to enhance the non-specificimmune 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 theimmunomodulatory effect of the Aegle marmelos was evaluated on the blood samples every 5 days untill 15 days afterinfection. The results obtained from the study shows that the 25 g leaf extract/kg of feed was found to be competentto enhance optimum immune response. The effectiveness of the immunostimulant action was found to be best forthe first 5 days after challenging with pathogen and subsequently, the immune response was found to decline in allthe concentrations of plant extract.Conclusion: The results of the study will be helpful for further investigation in the field to improve theimmunocompetence of fish against bacterial pathogens.