Abstract: Fresh feces from healthy poultry were collected for directional screening for candidate probiotic strains of Lactobacillus reuteri according to their host adaptation characteristics. Through 16S rDNA sequence analysis and pduC gene cluster screening, three reuterin-producing strains of L. reuteri were obtained. Their biological characteristics such as simulated gastrointestinal environment tolerance, antibiotic sensitivity, antibacterial activity of reuterin produced from glycerol by these stains and adhesion capacity to intestinal epithelial cells were evaluated. The results showed that L. reuteri WLRE01, WLRE03, and WLRE04 had strong acid (pH 2.5 and 3.5), bile salt (1.5 g/L) and simulated gastrointestinal juice resistance. After treatment with 1 mmol/L hydrogen peroxide for 6 h, the viable counts of L. reuteri WLRE03 and WLRE04 were almost kept unchanged. The produced reuterin had strong inhibitory effect on Staphylococcus aureus, with a diameter of inhibitory zone of (28.1 ± 1.2) mm. The three strains showed good adhesion capacity to HT-29 cells, and among them WLRE01 had the strongest adhesion capacity. In summary, all three strains from healthy poultry feces deserve further research as candidate probiotic strains.

Key words: Lactobacillus reuteri; directional screening; reuterin; tolerance; antibacterial activity; adhesion