| Summary: | 碩士 === 國立臺灣大學 === 生化科技學系 === 105 === Research demonstrated that diet-induced dysbiosis might play an important role in obesity, overgrowth of pathobionts are involved in obesity-related inflammation due to its cell wall component lipopolysaccharide. Rice bran is rich in valuable nutrients, mostly used as animal feed in the past, become popular nowadays due to prevalence of whole-food consumption concept. Dietary fiber of rice bran can be utilized by gut microbiota to produce SCFAs that have immuno-modulatory and anti-inflammatory effects. Thus, this research aims to investigate whether rice bran can reverse the effects of high-fat diet on gut microbiota and immune responses. Experiment 1 was to explore the effects of rice bran on gut microbiota in the conventional animal facility. Nine to ten-week-old Balb/c mice were fed with either high-fat (HF) diet or HF-diet supplemented with rice bran (HF-RB) for ten weeks, feces were collected and measured by 16S rDNA sequence analysis to amplify target microbiota gene. Results showed that the HF-RB group had lower Firmicutes, Enterobacteriaceae, higher Bactroidetes and Bacteroides compare with the HF group, suggesting the ability of rice bran to modulate gut microbiota., Further experiment 2, C57BL/6J mice were mated in our animal facility to avoid variations of gut microbiota in newborns due to maternal microbial transmission. Five-week-old mice were divided into four groups: normal fat (NF), HF, HF-RB, and HF supplemented with probiotics (HF-PRO) for 8 weeks’ feeding. First, we confirmed that HF-diet reduced fecal Bifidobacteria, Bacteoridetes, and increased Enterobacteriaceae. Both the HF-RB and the HF-PRO groups restored fecal Bifidobacterium and Enterobacteriaceae to the level of the NF group. In consistent with experiment 1, the HF-RB group had lower Firmicutes, and higher Bacteroidetes, Bacteroides compared with the HF group. Fecal SCFAs are significantly higher in the HF-RB group than those in the HF and the HF-PRO groups. Serum and fecal folate are also significantly higher in the HF-RB group. Cytokine secretion ability (IL-2, TGF-β) of isolated MLN cells in the HF-RB group was similar to the NF group. In conclusion, rice bran can lessen the effects of HF-diet on target gut microbiota, gut microbiota metabolites and gut immune responses.
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