Antibacterial effect of Polygonum chinense L. extract on pathogen bacteria of acute hepatopancreatic necrosis disease in brackish shrimps

Abstract

The study was conducted to evaluate the bactericidal effect of Polygonum chinense L. on the bacterial strain (Vibrio parahaemolyticus) causing acute hepatopancreatic necrosis disease (AHPND) in shrimps. The trunks and leaves of P. chinense L. trees were extracted by soaking in ethanol. Methods applied included: Kirby-Bauer disk diffusion susceptibility testing and tests on shrimps by feeding with the diet of 25-30 g/100 kg of shrimps and soaking with the concentration of 25-30 g/m3. The results showed that crude extracts of P. chinense L. had anti-bacterial effects on V. parahaemolyticus with the inhibition zone diameter of 19.8-20.6 mm at the concentration of 66.7200 μg/disc. In addition, using crude extracts added to water at the ratio of 30 g/m3 at 2 times (when the pathogenesis at the V. parahaemolyticus bacteria density of 105-106 cfu/ml and after 24 h), the survival rate was 60% compared with the control group 0%, while the method of herbal supplements to foods (25-30 g/100 kg of shrimps) was not effective because shrimps could not catch bait. The result achieved is a scientific basis for the development of herbal medicinal products to be effective in the prevention and treatment of AHPND towards biosafety and environmental friendliness.