Mandana Salehizadeh - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
Mohammad Hossein Modarressi - Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran
Seyed Naser Mousavi - Department of Animal Science, Varamin-Pishva Branch, Islamic Azad University, Varamin, Iran
Maryam Tajabadi Ebrahimi - Department of Biology, Faculty of Sciences, Central Tehran Branch, Islamic Azad University, Tehran, Iran

The efficacy of probiotics as alternatives to antibiotics has been defined as one of the potential strategies to prevent Salmonella spp. infection in poultry. The purpose of this study was to isolate probiotic native Lactic acid bacteria (LAB) with high compatibility to intestinal tract and prevention of Salmonella typhimuriumfrom broiler chicken feces. Thirty-seven samples of chicken feces were collected from seven broiler chicken farms in Northern Iran. The isolates identification was carried out with morphological and biochemical tests. Agar diffusion methods were used to evaluate the antimicrobial activities against Escherichia coli and S. typhimurium. The primary probiotic characteristics such as resistance to acid and bile and adhesion to Caco-۲ cells were studied. Indeed, the ability of LAB isolates to inhibit adhesion of S. typhimurium to Caco-۲ cells was evaluated by exclusion, competition and displacement assays. Among ۴۲ isolates, S۰۸, S۰۱ and S۰۶ isolates which showed appropriate probiotics characteristics were selected. Isolates S۰۸ and S۰۱ showed to be able to adhere strongly and also S۰۶ was adhered moderately. In the exclusion assay, the isolates S۰۸, S۰۱ and S۰۶ significantly hampered adhesion of S. typhimurium cell, in the competition assay, the isolates S۰۸, S۰۱ showed significant level of competition activity against S. typhimurium adherence to Caco-۲ cells and isolate S۰۸ showed the greatest displacement activity. The ۱۶S rDNA sequence revealed that S۰۸, S۰۱, and S۰۶ isolates were ۹۹.۰۰% similar to Lactobacillus salivarius, Lactobacillus johnsonii, and Pediococcus acidilactici, respectively. The result of this study suggested that LAB isolated from broiler chicken feces could be a remarkable reservoir for identification of probiotic to inhibit the pathogenic bacteria growth.

Antimicrobial activity, Broiler chicken, Probiotic