Abstract:
The objectives of this study were to investigate the mixed culture of Bacillus megaterium, B. subtilis and B. licheniformis called Pormor1, to control Acute Hepatopancreatic Necrosis Disease (AHPND) or EMS (Early Mortality Syndrome) in white shrimp Litopenaeus vannamei by produced Pormor1 in various water, sugar and sugar crane for microbial spawning and evaluated efficiency of Pormor1 in control of the infection in laboratory and aquaculture farm. The microbial spawning of Pormor1 revealed that freshwater was suitable for spawning that determined by the good growth of Bacillus and no growth of Vibrio, but not different in sugar and sugar crane for Pormor1 spawning. The efficiency of Pormor1 in control of the infection in the laboratory was investigated. The infected shrimps by Vibrio parahaemolyticus AHPND strain were divided into tanks and different feeding with either Bacillus megaterium, B. subtilis or B. licheniformis and feeding with Pormor1. The infected shrimps that were feed with Pormor1 showed the highest survival rate and revealed little detection of V. parahaemolyticus AHPND strain in their tissues by PCR (Polymerase Chain Reaction). In contrast, the infected shrimp feeding with each of Bacillus megaterium, B. subtilis or B. licheniformis revealed the spread of V. parahaemolyticus in all tissues by PCR. Five aquaculture farms of shrimp in Chanthaburi province with the preparation of pond by Pormor1 were monitored for V. parahaemolyticus infection in water, soil, and shrimp by PCR method. The result showed that the period time of V. parahaemolyticus AHPND strain detected was different by 1st and 4th Farms were rapidly V. parahaemolyticus detected. In contrast, 2nd, 3th, and 5th Farms were delay in V. parahaemolyticus detected by PCR. This study indicated that Pormor1 or the mixed culture of Bacillus was able to control disseminated of V. parahaemolyticus in shrimps especially in hepatopancreatic that is the target tissue of acute hepatopancreatic necrosis disease in white shrimp (Litopenaeus vannamei). Additionally, the aquaculture of shrimp with Pormor1 could be detected V. parahaemolyticus AHPND strain in sol, water, and shrimp. Although some farms were delay and some farms were rapidly detected of this pathogen by PCR, but all shrimps could be harvested for commercial. The result of this study revealed the efficiency and mechanism of Pormor1 to control the virulence of AHPND and support the use of Pormor1 in aquaculture of shrimp in Chanthaburi to avoid chemical and antibiotic treatment by using Pormor1 as a biological control.