RESVERATROL INHIBITS GROWTH, VIRULENCE AND BIOFILM FORMATION OF AEROMONAS HYDROPHILA

Resveratrol (Res) is an important active ingredient in Chinese herbal medicines such as rhubarb and polygonum cuspidatum with antibacterial, anti-inflammatory and antioxidant properties. To explore its application value in the prevention and treatment of bacterial diseases in aquatic animals, we explored the antibacterial activity of resveratrol against Aeromonas hydrophila, an important bacterial pathogen in freshwater aquaculture. The growth, biofilm formation, hemolysis inhibition, and virulence related gene expression of A. hydrophila under different resveratrol concentrations were detected. The in-vivo protection of resveratrol was confirmed by artificially infecting crucian carp with A. hydrophila. The results showed that the minimal inhibitory concentration (MIC) of resveratrol against A. hydrophila was above 1024 μg/mL, and the concentration less than 64 μg/mL did not affect the growth ratio of A. hydrophila. Resveratrol with more than 32 μg/mL significantly inhibited the biofilm formation and hemolytic activity of A. hydrophila (P<0.05) in a dose-dependent pattern. Resveratrol mediated heavy moisture of bacterium group sense of regulation and of QS system by inducing luxR and reucing luxS gene expression. The expression of omp was significantly down-regulated by resveratrol. Artificial infections showed that the mortality rate of allogynogenetic crucian carp infection in the 25—100 mg/kg resveratrol-treated group was significantly lower than that of the control group, and the expression of TNF-α and IFN-γ mRNA was significantly decreased. This study showed that resveratrol can effectively inhibit the viru-lence of A. hydrophila and reduce the inflammatory response at 2500 mg/kg on fish infected with A. hydrophila.