Investigation of Rhizopus oligosporus Metabolites in Fermented Wheat Bran and Its Bio Function in Alleviating Colitis in Mice Model.

Wheat bran (WB) is a low-value by-product of the wheat milling industry. Solid-state fermentation with Rhizopus oligosporus is performed to improve WB's nutritional quality (RH). Twenty-five mice (11-week-old C57BL/6N male mice) were divided into three groups. The first group was fed a control diet (n = 8), the second group a 10% WB-supplemented diet (n = 8), and the last group had a 10% RH-supplemented diet (n = 9). The diet treatment was administered for 4 days before dextran sodium sulfate (DSS, 3% in drinking water) was administered for 9 days. RH supplementation prevented bodyweight loss and reduced the disease activity index in mice. An increase in the level of SCFAs in mouse intestines was detected post-RH supplementation, suggesting that SCFAs might have contributed to its anti-colitis effect. Metabolome analysis was conducted to explore other bioactive compounds in RH. R. oligosporus fermentation significantly increased the amounts of ergothioneine, arginine, branched-chain amino acids, and adenosine in wheat bran. All of these compounds are known to have antioxidant and anti-inflammatory capacities. These bioactive compounds might also have contributed to the RH's ability to ameliorate DSS-induced colitis.