Inhibitory activity of native probiotic Bacillus vallismortis IS03 against pathogenic Vibrio harveyi under in vitro and in vivo conditions in Litopenaeus vannamei

Abstract

An excellent alternative for chemical antimicrobial agents to prevent disease in the shrimp aquaculture is the application of effective probiotics. The present study was evaluated the effect of Bacillus vallismortis IS03 as a native probiotic, isolated from digestive tract of Litopenaeus vannamei on pathogenic Vibrio harveyi under in vitro and in vivo circumstances. Co-cultivation of V. harveyi and B. vallismortis showed significantly (P<0.05) decreased the growth of V. harveyi in the treatment groups compared to the control. Cell-free extracts of B. vallismortis IS03 exhibited more appropriate antibacterial effects on replication of V. harveyi. The highest and lowest inhibitory effects were respectively shown in10 8 and 10 6 CFU ml-1 of B. vallismortis IS03 cell-free extracts. The probiotic potential of B. vallismortis IS03 was assessed through the groups of control and the experiments 10 6 , 10 7 and 10 8 CFU ml-1 salt water once every 3 days from zoea1 process to end point of the study.