Isolation of Lactobacillus salivarius and Lactobacillus crispatus strains from chicken gastrointestinal tract, having inhibitory effect on Salmonella enteritidis and Escherichia coli growth

Probiotics are live cultures of microbes – often lactic acid bacteria but also some other species – fed to animals in order to improve health and growth by altering intestinal microbial balance. Here, we isolated and identified some lactic acid bacteria (LAB) with probiotic properties, from healthy chicken gastrointestinal (GI) tract. Systematic procedures were used to evaluate the probiotic properties of isolated lactic acid bacteria from the microflora of different parts of the GI tract. LAB were examined for the major properties included resistance to 2% bile salt and acidic pH, capability to adhere to the intestinal epithelium and their inhibiting effects on some pathogenic bacteria including Salmonella enteritidis (S. enteritidis) and Escherichia coli (E. coli) growth. Fermentation profile analysis and the sequencing results of conserved 16S rRNA genes showed that 4 clones isolated from duodenum and caeca were Lactobacillus salivarius and the other one clone, also isolated from the duodenum, showed out to be Lactobacillus crispatus. All of the selected LAB were able to adhere to the epithelial cells from chicken. Our results revealed the lactobacilli isolated from different parts of the intestine have the probiotic properties required for use in animal feed. Because the inhibitory effect of these isolated lactic acid bacteria on growth of pathogenic microflora, we suggest that these probiotic bacteria can represent good candidates for therapy against infectious gastrointestinal diseases in chickens.