Insoluble dietary fiber (non-starch polysaccharides) from rice bran attenuates cadmium-induced toxicity in mice by modulating the gut microbiota and alleviating liver and kidney injury

Cadmium (Cd) is a toxic heavy metal and leads to various altered physiological functions, which are harmful to health. This study aimed to evaluate the protective effect of insoluble dietary fiber from rice bran (RBIDF, non-starch polysaccharides) against Cd-induced toxicity in mice. The results showed that Cd exposure caused a significant decrease in body weight and that RBIDF recovered the body weight gain of mice ( P < 0.05). Moreover, RBIDF reversed the decrease of liver and kidney weight, and the increase of serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatinine (CREA) and urea (UREA) levels. The histopathological results showed that RBIDF alleviated severe liver damage induced by Cd exposure, and improved liver cell injury and glomerulus destruction. RBIDF also decreased the Cd accumulation in the intestine and Cd absorption and increased Cd content in mouse feces ( P < 0.05). In addition, at phylum level, RBIDF increased Bacteroidetes abundance, while decreased Firmicutes and Proteobacteria abundances. At genus level, it increased Lactobacillus abundance as well. It could be seen that RBIDF ameliorated the Cd-induced decrease in gut microbiota disorders. The results indicated that RBIDF was an effective component in the daily diet against Cd toxicity. • RBIDF ameliorated liver and kidney damage caused by cadmium. • RBIDF maintained body weight and promoted the excretion of feces of cadmium. • RBIDF restored bacterial community structure and composition of gut microbiota.