Evaluation Of Probiotic Properties Of Lactobacillus Plantarum WLPL04 From Breast Milk And Its Benefical Effects On The Immunity And Intestinal Microbiota In Mice

Lactic acid bacteria(LAB) are generally regarded as the important class of probiotics, due to their benefits e.g antagonistics, nutrition and immunity for the host during its gastrointestinal colonization. LAB were often ultilized in dairy products to improve the flavor, prevent the invention of pathogent, maintain the host health. Lactobacillus plantarum WLPL04 was screened out from breast milk, descripsion of its biology properties is the premise for development of probiotics products.In this study, Lactobacillus plantarum WLPL04, was investigated for its survival capacity(acid and bile salt tolerance, survival in simulated gastrointestinal tract, antibiotic susceptibility) and probiotic properties(yield of exopolysaccharides, inhibition on pathogens, anti-adhesion of pathogens, protection from SDS harmful effect, anti-inflammatory stress on Caco-2 cells, and modulating intestinal flora). The results showed that L. plantarum WLPL04 was able to survive at pH 2.5 for 6 h and 0.45% bile salt for 24 h, suggesting that it can survive well in the gastrointestinal tract. Antibiotic susceptibility tests showed that L. plantarum WLPL04 was susceptible to 8 kind of antibiotics(erythromycin, streptomycin, gentamicin, nitrofurantoin, tetracycline, chloramphenicol, amoxicillin and penicillin) and resistant to 6 kind of antibiotics(rifampicin, kanamycin, bacitracin, Polymyxin B, ciprofloxacin and Nalidixic acid). In addition, L. plantarum WLPL04 had a broad spectrum against Gram-positive strains(Listeria monocytogenes CMCC 54007, Bacillus cereus ATCC 14579 and Satphylococcus aureus CMCC 26003) and Gram-negative strains(Pseudomonas aeruginosa MCC 10104, Shigellasonnei ATCC 25931, Enterobactersa kazakii ATCC 29544, Salmonella typhimurium ATCC 13311 and Escherichia coli O157:H7). Furthermore, the exopolysaccharide yielding of L. plantarum WLPL04 reached the highest amount of 426.73 ± 65.56 mg/L at 24 h.With strategies of competition, inhibition and replacement, L. plantarum WLPL04 reduced the adhesion of E. coli O157:H7(35.51%), S. typhimurium ATCC 13311(8.10%) and S. aureus CMCC 26003(40.30%) on Caco-2 cells by competition, and subsequent by 59.80%, 62.50% and 42.60%, respectively, for above 3 pathogens through inhibition style, and by 75.23%, 39.97% and 52.88%, respectively, through displacement style. L. plantarum WLPL04 attenuated the acute stress induced by SDS on Caco-2 cells and significantly inhibited the inflammatory cytokines(IL-6, IL-8 and TNF-?) expression on Caco-2 cells but increased IL-10 expression in vitro when compared with Salmonella group(p<0.01).To study the effects of Lactobacillus plantarum WLPL04 on the immunity and hepatorenal function, the body weight and immune organ indices were measured by feeding BABL/c mice with WLPL04. To investigate the effect Lactobacillus plantarum WLPL04 on gut microbiota, the Real-time PCR was used. The results indicated that the WLPL04 significantly increased the growth of Lactobacilli and Bifidobacterium on jejunum and faeces, and exerted an inhibition effect on growth of Enterococci on feces after gavage WLPL04 for 7 and 14 days; the number of Lactobacilli on gut microbiota was relatively higher than that in control group when stopoing gavage of L. plantarum WLPL04 and normal feeding for 2 and 7 days.In conclusion, L. plantarum WLPL04 exhibited strong antimicrobial activity against various pathogens, high survival ratio in simulated gastrointestinal tract, effect of anti-adhesion and anti-inflammation induced by pathogens. Meanwhile, it played a balance role for selectively promoting the growth of probiotics and inhibiting pathogen, and had none effect on immune organs and index, and inflammatory of host. Therefore, our results provided a database and reference for the research and development of L. plantarum WLPL04 as a probiotic candidate.