ANTIBACTERIAL ACTIVITY OF COCONUT SHELL LIQUID SMOKE AGAINST Vibrio parahaemolyticus CAUSING AHPND IN WHITELEG SHRIMP (Litopenaeus vannamei)

Abstract

Acute hepatopancreatic necrosis disease (AHPND), caused by Vibrio parahaemolyticus, is a major bacterial disease that significantly impacts Litopenaeus vannamei aquaculture. The use of natural antibacterial agents has gained increasing attention as an alternative to antibiotics. This study aimed to evaluate the antibacterial activity of coconut shell liquid smoke against V. parahaemolyticus using an in vitro disc diffusion method. A completely randomized design was applied with five concentrations of liquid smoke (0.5, 1.0, 1.5, 2.0, and 2.5%), along with positive (chloramphenicol) and negative (distilled water) controls, each with three replications. Antibacterial activity was assessed by measuring the diameter of inhibition zones after 24 hours of incubation. The results showed that coconut shell liquid smoke exhibited significant antibacterial activity against V. parahaemolyticus. The highest inhibition zone was observed at 1.0% concentration (18.03 mm), followed by 0.5% (13.63 mm), both categorized as strong inhibition. However, the antibacterial effect did not increase proportionally with concentration, indicating a non-linear response. The positive control showed a very strong inhibition zone (26.5 mm), while no inhibition was observed in the negative control. In conclusion, coconut shell liquid smoke demonstrates strong potential as a natural antibacterial agent against V. parahaemolyticus. Further in vivo studies are recommended to evaluate its effectiveness in shrimp culture systems for sustainable AHPND management.