Effects of oxidized konjac glucomannan on metabolic health and gut microbiota in ICR mice

Oxidized konjac glucomannan (OKGM) is a type of depolymerized konjac glucomannan (KGM) prepared by oxidation. It has a potential application as a food additive with unique physicochemical properties. This work investigated the effects of OKGM on metabolic health and gut microbiota in ICR mice by a 90-day oral toxicity experiment. ICR mice (12/sex/group) were fed diets containing 0%, 2.5%, 5.0%, and 7.5% of OKGM (weight/weight) for 13 weeks. According to the subchronic study results, the overall health, body weight gain, food consumption and clinical pathology parameters were comparable between the OKGM groups and the control. OKGM induced no adverse effects in this study. The no observed adverse effect level (NOAEL) was 7.5% in the diet (equivalent to 10.21 and 12.01 g/kg body weight/day in male and female mice, respectively). Besides, the OKGM showed a positive regulatory effect on mouse gut microbiota. The OKGM intake reduced the relative abundance of Firmicutes and increased the relative abundance of Bacteroidetes in the mouse gut microbiota. Furthermore, intake of OKGM increased the relative abundance of Lactobacillus, especially Lactobacillus reuteri. Hence, the OKGM has the potential to be a source of functional food additives.