The aim of this study was to evaluate the effects of three different kinds of
oligosaccharides (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 g per d per kg bw and 8 g per d per kg bw on the composition and activity of the microbiota in the gut of mice with
constipation induced by
loperamide.
Oligosaccharides were intragastrically administered to specific pathogen-free BALB/c mice once per day for 17 days. Feces were collected during a feeding trial and subjected to 16S
rDNA amplicon analysis.
Constipation indices, changes in gut microbiota and metabolic activity were measured to evaluate the effects of the
oligosaccharides. The results show that
oligosaccharides treated
constipation by increasing both the water content of the feces and the small intestinal transit rate. The dosage required to treat
constipation was different for different
oligosaccharides. High-dose GOS90 was the most effective in relieving
constipation, followed by medium-dose FOS95 and IMO90. The fecal samples were investigated after the
oligosaccharide treatment. All three
oligosaccharides increased the ratio of
acetic acid and decreased the ratio of propionic and
butyric acids in the feces. The increase in the ratio of
acetic acid and the concentration of
butyric acid were found to have relatively larger effects on
constipation.
After treatment with
oligosaccharides, the gut microbiotas of the mice were dominated by Firmicutes, Bacteroidetes and Actinobacteria. At the genus level,
oligosaccharide treatment increased the levels of Lactobacillus and Bifidobacterium and decreased the levels of Odoribacter, Alistipes and Bacteroides. In conclusion, our results demonstrate that
oligosaccharides administered as a dietary supplement increase the water content of feces, reduce intestinal transit time, modulate the composition of the gut microbiota and increase the concentration of
short-chain fatty acids in the feces of mice with
constipation.