Study on the ability of partially hydrolyzed guar gum to modulate the gut microbiota and relieve constipation

The aim of this study was to evaluate the effects of high- (HHGG, Mw 10,000-30,000 Da) and medium-molecular-weight (MHGG, Mw 2,000-10,000 Da) partially hydrolyzed guar gum (PHGG) on modulation of gut microbiota and relief of constipation in mice. Mice were treated with galacto-oligosaccharide (GOS) and xylo-oligosaccharide (XOS) at a dose of 1 g/kg bw as positive controls. Low- and high-dose HHGG and MHGG groups received 250 mg or 1 g/kg bw, respectively. Treatment was administered intragastrically for 15 days, and constipation model was induced by loperamide lavage at d 16. PHGG could increase fecal moisture and small intestinal transit and shortened the time to first black stool defecation after constipation. The highest short-chain fatty acid production was observed in the high-dose MHGG group. Additionally, PHGG, GOS, and XOS predominantly promoted the accumulation of Bacteroidetes and inhibited the growth of Desulfovibrio. This study suggested that MHGG treatment could elicit constipation relief in mice. PRACTICAL APPLICATIONS: In this study, partially hydrolyzed guar gum (PHGG) produced by mannanase hydrolysis was applied for the relieving constipation in mice. The medium-molecular-weight product (Mw 2,000-10,000 Da) could elicit constipation relief and modulate the gut microbiota in mice, which shows the potential to act as dietary fiber for constipation treatment.