Probiotic potential and function of a Lactobacillus strain L1 isolated from Silage

One strain L1 was isolated from silage and identified as Lactobacillus rhamnosus confirmed by sequencing of its 16S rDNA genes. The isolate in this study showed sensitive traits to antibiotics, including the clinically relevant antibiotic tetracycline. It showed inhibition against pathogen E. Coli, good adhesion ability to epithelial intestinal cell line LS‐174T and the strong competitive exclusion of E. coli adhesion to LS‐174T (84.1% exclusion). The gastrointestinal transit proved the strain survived well using a simulation of conditions. What's more, L1 induced slight cytokines to provoke an inflammatory response, but not lead to cell damage. Due to its capabilities to protect the host, L1 is good candidate for further studying potential benefits that support its use as probiotic, then the in vivo immunodulatory effects were investigated. The effect of the long‐term administration of skim milk containing L1 on the immune response in mice was analyzed. Values for CD3⁺, CD4⁺, and CD8⁺ cell populations were increased in relation to the control. The results obtained in this study suggest that the L. rhamnosus strain L1 has potential for use as probiotic and is likely to be immune‐enhancing for human use. PRACTICAL APPLICATION: Lactobacillus belong to lactic acid bacteria that occur frequently in large numbers in various foods including vegetable, meat, and dairy products. Several properties may be evaluated to prove the potential of the bacteria before using them as probiotics. In this study, one of the Lactobacillus strains L1 isolated from the mixed grass and corn stalk silage exhibited above‐average results in all criteria observed in vitro including antibiotic susceptibility, antimicrobial activity, tolerance to gastrointestinal conditions, adhesion to intestinal cells, competitive exclusion of E. coli adhesion to epithelial cells, stimulation of immunity and benefit in animal experiment. The findings of our study suggest that L1 isolated from the silage may be potential probiotic for human use.