Effect of Punica granatum solvent extracts on immune system and disease resistance in Paralichthys olivaceus against lymphocystis disease virus (LDV)

We report the effect of aqueous, ethanol, and methanol solvent leaf extracts of Punica granatum on innate immune mechanisms, such as phagocytosis activity, respiratory burst activity, alternative complement activity, lysozyme activity and functional immunity in terms of percentage cumulative mortality and Relative Percent Survival (RPS) in olive flounder Paralichthys olivaceus naturally infected with lymphocystis disease virus (LDV) after 8 weeks. Infected fish were intraperitoneally administered with 0, 5, 50, and 100 mg kg−1 body weight of solvent extracts. In groups treated with 50 and 100 mg kg−1 body weight, the chosen innate immune parameters significantly increased after 8 weeks when compared to 0 mg kg−1 dose, but not with 5 mg kg−1. Administration of P. granatum solvent extracts for 8 weeks significantly reduced the percentage mortality with the consequent increase in RPS. The results suggest that intraperitoneal administration of the leaf extracts of P. granatum at 50 or 100 mg kg−1 dose clearly enhance the innate immune responses and disease resistance after 8 weeks in P. olivaceus against natural LDV infection.