Lactulose significantly increased the relative abundance of Bifidobacterium and Blautia in mice feces as revealed by 16S rRNA amplicon sequencing

Abstract

BACKGROUND Lactulose was one of the earliest prebiotics to be identified. To assess the potential risk of large intakes of lactulose to the intestinal microbiota, mice were fed a diet containing lactulose (0%, 5% and 15%, w/w) for 2 weeks and the changes in the fecal microbiota were evaluated by 16S rRNA high‐throughput sequencing. RESULTS Lactulose intervention decreased the α‐diversity of the fecal microbiota in both low‐dose and high‐dose groups. The relative abundance of Actinobacteria was significantly increased, while that of Bacteroidetes was significantly decreased after lactulose intervention. At the genus level, the relative abundance of Bifidobacterium belonging to Actinobacteria was significantly increased, and that of Alistipes belonging to Bacteroidetes was decreased in both low‐dose and high‐dose groups. The relative abundance of Blautia was significantly increased from 0.2% to 7.9% in the high‐dose group and one strain of Blautia producta was isolated from the mice feces. However, the strain could not utilize lactulose. CONCLUSION Overall, the microbial diversity was decreased after lactulose treatment, with significant increases in the relative abundance of Bifidobacterium. We also provide a strategy to increase the relative abundance of Blautia in the intestine by lactulose feeding at high doses, although the mechanism is not revealed. This will help us understand the prebiotic effect of lactulose on the host health. © 2021 Society of Chemical Industry.