Inhibitory Effects of Lactobacillus salivarius and Lactobacillus crispatus Isolated from Chicken Gastrointestinal Tract on Salmonella enteritidis and Escherichia coli Growth

Probiotics are live cultures of microbes; often lactic acid bacteria, but also some other species, which when fed to animals, improve their health and growth through altering the intestinal microbial balance. In the present research, healthy chickens’ gastrointestinal (GI) tracts were screened for the presence of lactic acid bacteria with probiotic properties. The probiotic properties of the isolates taken from different parts of the GI tract were evaluated. They were examined for resistance to 2% (w/v) bile salts and acidic pH, capability to adhere to the intestinal epithelium and inhibitory effects on the growth of Salmonella enteritidis and Escherichia coli. Fermentation profile analyses and sequencing data of the conserved 16S rRNA genes showed that from a total of five selected clones, four clones isolated from the duodenum and caeca were Lactobacillus salivarius and the fifth clone, isolated from the duodenum, was Lactobacillus crispatus. All the selected clones were able to adhere to the chicken’s epithelial cells. The lactobacilli isolated from different parts of the GI tract had probiotic properties suitable for use in animal feed. Due to the inhibitory effects of the isolated lactic acid bacteria on the growth of pathogenic microbiota, it can be concluded that these bacteria are good candidates for treatment of chicken GI infectious diseases.