Potential probiotic properties of lactic acid bacteria isolated from the intestinal mucosa of healthy piglets

In the present study, the probiotic properties of 52 lactic acid bacteria strains, isolated from the intestinal mucosa of 60-day-old healthy piglets, were evaluated in vitro in order to acquire probiotics of potential application. Based on acidic and bile salt resistance, 11 lactic acid bacteria strains were selected, among which 1 was identified as Pediococcus acidilactici, 3 as Enterococcus faecium, 3 as Lactobacillus rhamnosus, 2 as Lactobacillus brevis, and 2 as Lactobacillus plantarum by 16S rRNA gene sequencing. All selected strains were further investigated for transit tolerance in simulated upper gastrointestinal tract, for adhesion capacity to swine intestinal epithelial cells J2 (IPEC-J2), for cell surface characteristics including hydrophobicity, co-aggregation and auto-aggregation, and for antimicrobial activities. Moreover, hemolytic, bile salt hydrolase and biogenic amine-producing abilities were investigated for safety assessment. Two E. faecium (WEI-9 and WEI-10) and one L. plantarum (WEI-51) exhibited good simulated upper gastrointestinal tract tolerance, and showed high auto-aggregation and co-aggregation with Escherichia coli 1570. The strains WEI-9 and WEI-10 demonstrated the highest adherence capacity. The 11 selected strains mentioned above exhibited strong antimicrobial activity against E. coli CVCC1570, Staphylococcus aureus CVCC1882 and Salmonella pullorum AS1.1859. None of the 11 selected strains, except WEI-9 and WEI-33, exhibited bile salt hydrolase, hemolytic or biogenic amine-producing abilities. This work showed that the E. faecium WEI-10 and L. plantarum WEI-51were found to have the probiotic properties required for use as potential probiotics in animal feed supplements.