Exploiting green-synthesized silver nanoparticles to combat aquaculture pathogens in Barytelphusa cunicularis (Westwood in Sykes, 1836)
摘要
Green synthesis of silver nanoparticles (AgNPs) offers a sustainable approach to control bacterial infections in aquaculture systems. In this study, AgNPs were synthesized using Catunaregam spinosa leaf extract and optimized for concentration, pH, temperature, and incubation time. The optimized conditions (1 mM AgNO₃, 10% plant extract, pH 7, 37 °C, 24 h) produced well-dispersed, stable nanoparticles with a total yield of 568.4 mg (14.2%). The biosynthesized AgNPs were characterized using UV–Vis spectroscopy, XRD, FTIR, DLS, Zeta potential, and SEM–EDX analyses. Their antibacterial activity was evaluated against five bacterial strains isolated from injured freshwater crabs Barytelphusa cunicularis: Citrobacter braakii (PP832928), Aeromonas caviae (PP832929, PP832943), Citrobacter portucalensis (PP832930), and Citrobacter freundii (PP832944). The AgNPs exhibited significant antibacterial effects, with minimum inhibitory concentrations ranging from 50 to 100 μg.mL−1 and the highest zones of inhibition against C. portucalensis (13 mm) and A. caviae (12 mm). Additionally, the nanoparticles demonstrated antioxidant potential, with dose-dependent DPPH radical scavenging activity up to 47% at 100 μg.mL−1. These results indicate that green-synthesized AgNPs are stable, eco-friendly, and effective antibacterial and antioxidant agents, with promising applications in aquaculture for disease management and improving the health of freshwater crustaceans.