Antimicrobial Activity of Averrhoa bilimbi (Lin) Against Vibrio parahaemolyticus in the Culture of Penaeus monodon Post Larvae: An In Vitro and In Vivo Study

Vibriosis, caused by Vibrio parahaemolyticus, poses a significant challenge in the cultivation of Penaeus monodon. This study evaluated the antimicrobial activity of Averrhoa bilimbi L. leaf extract against V. parahaemolyticus using both in vitro (disk diffusion assay) and in vivo (shrimp immersion and challenge test) methods. Phytochemical screening revealed the presence of flavonoids, tannins, saponins, alkaloids, steroids, and phenols in the extract. The highest inhibition zone (15.33 mm) was observed at a concentration of 64 mg/mL, which also corresponded to the minimum inhibitory concentration (MIC). In the in vivo experiment, P. monodon larvae treated with 40 mg/L of A. bilimbi extract exhibited the highest survival rate (96%) following bacterial challenge. Clinical observations showed that untreated shrimp displayed symptoms such as body reddening and high mortality, whereas treated groups demonstrated enhanced resistance to infection. These findings suggest that A. bilimbi L. leaf extract has strong potential as a natural antibacterial agent for controlling V. parahaemolyticus infection in shrimp aquaculture systems.