Metagenomic insights into the effects of oligosaccharides on the microbial composition of cecal contents in constipated mice

The aim of this study was to evaluate the effects of different kinds of oligosaccharides on cecal microbiota. These oligosaccharides were a fructo-oligosaccharide (FOS) formulation consisting of 95% FOS (FOS95), a galacto-oligosaccharide (GOS) formulation consisting of 90% GOS (GOS90), and an isomalto-oligosaccharide (IMO) formulation consisting of 90% IMO (IMO90), at dosages of 0.8, 4, and 8 g/d/kg bw. FOS95, IMO90, and GOS90 were each gavaged to BALB/c mice for 14 days. Sequencing of 16S rDNA amplicons showed that the abundance of Actinobacteria and TM7 dramatically decreased in constipation group. Feeding constipated mice with FOS95, IMO90, and GOS90 resulted in decreased ratio of Firmicutes to Bacteroidetes, and increased abundances of Bifidobacterium, Bacteroides, Rikenella, Lactobacillus, and Clostridium and decreased abundances of Oscillospira, Coprococcus, and Dorea at the genus level. Overall, our results demonstrate that FOS95, IMO90, and GOS90 modulate the cecal microbiome in constipated mice.