Evaluation of Actinobacteria in prevetion of Vibrio parahaemolyticus Acute cause Hepatopancreatic Necrosis

Abstract

Virulence plasmid strains V. parahaemolyticus was reported as pathogenesis of AHPND (Acute Hepatopancreatic Necrosis Disease) in 2013. It was very complicated to treat V. parahaemolyticus in the sediment of the pond, so that AHPND disease usually appears at early stage about 45 days after stocking with percentage of mortality shrimp about 80 - 100%. The main objective was to isolate the actinobacteria against pathogenic AHPND V. parahaemolyticus from natural sediment sources. As the result, X381 strains was one of 29 actinobacteria strains showed antagonistic properties against to pathogenic V. parahaemolyticus with halo zones about 10-45 mm. In addition, the efficacy of the bio-granules in competition to V. parahaemolyticus was tested by co-culture experiment. The result demonstrated that at 15 to 40 bio-granules per 50 ml nutrient broth could significantly reduce the density of V. parahaemolyticus comparing with control group during 24 hours and V. parahaemolyticus completely treated after 30 hours. In vivo condition, applying the water treatment with 4.5x103 spore-X381 strain/15L was showed the relative percent survival shrimp is 74%, while feeding 3.34x105 CFU/g was demonstrated RPS (%) equal 53.7% after challenge test 1.2x106 V. parahaemolyticus CFU/mL. Therefore, actinobacteria (X381) revealed promising antagonistic activity against V. parahaemolyticus and extended the life span of shrimps. Keywords: Actinobacteria (X381), AHPND, V. parahaemolyticus, co-culture, water treatment, feeding. RPS (%) 1