Enhanced immune response and resistance to white tail disease in chitin-diet fed freshwater prawn, Macrobrachium rosenbergii

•We determine the effect of chitin on immunomodulation of M. rosenbergii.•Increased phenoloxidase and respiratory burst activity in chitin-diet fed prawns.•High RPS in chitin-diet fed M. rosenbergii challenged with MrNV and XSV.•Dietary incorporation of chitin is required for immunostimulation in M. rosenbergii.

Chitin is one of the natural biopolymer found abundantly in the shells of crustaceans, insects and in cell walls of fungi. In this study, we determined the effect of dietary administration of 0.5, 0.75 and 1% chitin on the immune response and disease resistance in freshwater prawn, challenged against Macrobrachium rosenbergii nodavirus (MrNV) and extra small virus (XSV). We observed a significantly enhanced immune response, indicated as higher prophenoloxidase activity and respiratory burst of hemocytes, in 0.75% chitin-diet fed prawns compared to the chitin-free-diet fed prawns. Importantly, the relative percent survival (RPS) following challenge with white muscle disease (WTD) viruses was found relatively high in M. rosenbergii fed with diet containing 0.75% chitin (63.16%), suggesting an increased resistance to disease susceptibility. These results indicate that the incorporation of chitin in prawn diet would be beneficial in stimulating the immune response and thereby developing resistance against diseases.