Dynamic analysis of human small intestinal microbiota after an ingestion of fermented milk by small-intestinal fluid perfusion using an endoscopic retrograde bowel insertion technique

ABSTRACT

Probiotic products have been shown to have beneficial effects on human hosts, but what happens in the gastrointestinal tract after its ingestion remains unclear. Our aim was to investigate the changes within the small intestines after a single intake of a fermented milk product containing a probiotic. We have periodically collected the small-intestinal fluids from the terminal ileum of seven healthy subjects for up to 7 h after ingestion by small-intestinal fluid perfusion using an endoscopic retrograde bowel insertion technique. The bacterial composition of the terminal ileum clearly revealed that the ingested probiotics (Lactobacillus casei strain Shirota: LcS and Bifidobacterium breve strain Yakult: BbrY) occupied the ileal microbiota for several hours, temporarily representing over 90% of the ileal microbiota in several subjects. Cultivation of ileal fluids showed that under a dramatic pH changes before reaching the terminal ileum, a certain number of the ingested bacteria survived (8.2 ± 6.4% of LcS, 7.8 ± 11.0% of BbrY). This means that more than 1 billion LcS and BbrY cells reached the terminal ileum with their colony-forming ability intact. These results indicate that there is adequate opportunity for the ingested probiotics to continuously stimulate the host cells in the small intestines. Our data suggest that probiotic fermented milk intake affects intestinal microbes and the host, explaining part of the process from the intake of probiotics to the exertion of their beneficial effects on the host.

KEYWORDS:

• Bifidobacterium breve strain Yakult
• colony-forming ability
• endoscopic retrograde bowel insertion
• fermented milk
• human
• ileal microbiota
• Lactobacillus casei strain Shirota
• microbiomics
• probiotics
• small-intestinal fluid perfusion

Disclosure of potential conflicts of interest

T. Takada, K. Shimizu, K. Oana, M. Katto, Y. Nagara, H. Makino, A. Kushiro, & K. Oishi are employee of Yakult Honsha Co., Ltd, Tokyo, Japan. Test beverages used in this study were produced by Yakult Honsha Co., Ltd, Tokyo, Japan.

Supplementary data

Supplemental material for this article can be accessed on the Publisher’s website.

Author contribution

K.Oi, A.K., and S.F. directed the study. T.T., A.K., K.Oi, D.C., T.M., and S.F. designed the study. T.T, K.S., K.Oa, M.K, Y.N., K.Oi, D.C., T.M., T.A., K.M., and S.H. conducted the experiments. T.T., K.S., Y.N., H.M, and D.C. analyzed the data. T.T., K.Oi, K.S., Y.N., H.M., K.Oa, D.C., A.K., and S.F. reviewed the manuscript.

Ethics approval

This study was approved by the Ethics Committee of the Graduate School of Medicine at Hirosaki University (UMIN ID: UMIN000018128) and conducted in compliance with ethical principles from the Declaration of Helsinki, guidelines of good clinical practice, and applicable regulations.