Effect of Lactobacillus reuteri on intestinal microbiota and immune parameters: Involvement of sex differences

Probiotic candidate Lactobacillus reuteri DMSZ 8533 was screened out in vitro based on a relatively higher gastrointestinal tolerance and moderate adhesiveness. The organ index (spleen, thymus and liver), Interleukin-12 (IL-12), tumor necrosis factor-alpha (TNF-alpha), T-lymphocytes (CD3-, CD4- and CD-8 positive cells) and fecal microbiota composition were also investigated in BALB/c mice. Results showed a significant higher level of IL-12 at low-dose L. reuteri treated group in both females and males. The relative abundance of phylotypes in the phylum Bacteroidetes and Firmicutes exhibited a reserve shift between sexes after L. reuteri intervention. Meanwhile, the relative abundance of several taxa also differed markedly between sexes at low-dose group, together with microbiota diversity. Our finding demonstrates the importance of L. reuteri DMSZ 8533 as a potential probiotic strain with an immunomodulatory effect, which could also alter the microbiota composition depending on the sex of the host.