The Efficacy of Potential Probiont Bacillus amyloliquefaciens Strain L11 in Protecting Artemia Nauplii and Blue Crab Juveniles against Vibrio harveyi Infection

In this study, Bacillus amyloliquefaciens strain L11 was used as potential probiont in preliminary in vivo assay using Artemia and blue crab juveniles as final host. Strain L11 at 108 CFU mL-1 was found able to penetrate into gnotobiotic Artemia as early as 6h exposure. The survival rate of Artemia incubated with strain L11 at concentration of 106 CFU ml-1 and challenged with V. harveyi was 62 ± 1%. The numbers of Vibrios in Artemia were reduced at the end of the challenge assay. The in vivo assay using blue crab juveniles, demonstrated that strain L11 at 106 CFU mL-1 showed significant survival (42 ± 1 %) compared with group challenged with V. harveyi with no probiont added (12 ± 1 %) after five days of exposure. Strain L11 also able to reduce the number of Vibrios and increased the weight of the juveniles