Evaluation of antimicrobial activity of isolated bacteria from white shrimp (Litopenaeus vannamei) intestine, water and sediment in Choebde, Abadan

Using of probiotics as organisms that can cause increasing the health and resistance to disease in host, can be reduced the use of antibiotics in aquaculture. In this study, isolation of lactic acid bacteria, Enterococcus sp. and Bacillus sp. from the intestine, water and sediment of the environment of Litopenaeus vannamei from Choebde region of Abadan, Khuzestan, done firstly and then the antimicrobial activity of isolated bacteria against Vibrio harveyi, Yersinia ruckeri, Aeromonas hydrophila and Lactococcus garvieae in two methods of agar well diffusion assay and Cross streak assay, were investigated. Based on the obtained results none of the Bacillus and Enterococcus isolates showed any antimicrobial activity against pathogenic bacteria with both methods but most isolates of acidic bacteria had antimicrobial activity. Afterward three isolates of bacteria with the highest antimicrobial activity (isolates 93, 94 and 95) were identified by sequencing of 16 S rRNA and all of three isolates were identified as strains of Lactobacillus plantarum after the sequencing.  Therefore, based on the results of this study, these isolates can be used for the purposes of probiotic in aquaculture, especially shrimp industry in the country, after invitro and invivo studies.