香蕉抗性淀粉对C57BL/6J肥胖小鼠肠道放线菌群的调控作用

目的:研究不同剂量香蕉抗性淀粉(resistant starch,RS)对高脂饮食诱导的C57BL/6J肥胖小鼠肠道放线菌群多样性的影响。方法:将40只C57BL/6J小鼠随机分为5组,分别采用普通饲料(CONV)、高脂饲料(HF)以及添加5%、10%、15%香蕉抗性淀粉的高脂饲料(5%RS+HF、10%RS+HF、15%RS+HF)进行饮食干预,8周后采用变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)技术对小鼠粪便样本放线菌菌群组成进行分析,采用实时荧光定量聚合酶链式反应技术对小鼠粪便样本双歧杆菌数量进行比较。结果:DGGE图谱分析显示,HF组聚类与其余4组彻底分离,抗性淀粉各组趋于成簇但无明显界限。5%RS+HF组与15%RS+HF组放线菌多样性和丰富度方面均显著低于CONV组与HF组(P0.05),10%RS+HF组多样性和丰富度较另外2组RS+HF组有所上升。高脂饲料能够极显著降低肠道中双歧杆菌数量(P0.01),而10%和15%香蕉抗性淀粉的加入均高度显著增加双歧杆菌数量(P0.001)。结论:香蕉抗性淀粉可恢复肥胖小鼠肠道放线菌群多样性,显著促进双歧杆菌生长,且具有剂量依赖关系。

Regulative Effect of Dietary Banana Resistant Starch on Gut Actinobacteria in Obese C57BL/6J Mice

To study the impact of a high-fat diet supplemented with different doses of banana resistant starch (RS) on the diversity of gut Actinobacteria in obese C57BL/6J mice, 40 mice were randomly divided into five groups, which were fed a conventional diet (CONV), a high-fat diet (HF) alone, supplemented with 5% (5% RS + HF), 10% (10% RS + HF), and 15% (15% RS + HF) of RS, respectively. After 8 weeks of dietary intervention, denaturing gradient gel electrophoresis (DGGE) was used to monitor the changes in the composition of gut Actinobacteria in mice. The amounts of fecal Bifidobacterium were compared among the five groups of animals by real-time fluorescence quantitative polymerase chain reaction (PCR). Cluster analysis of the DGGE profiles showed that the HF group was significantly different from the other 4 groups. All the RS groups tended to form a cluster without obvious boundaries. In addition, the diversity and abundance of Actinobacteria in the 5% RS + HF and 15% RS + HF groups were significantly lower than in the CONV and HF groups (P < 0.05) and also lower than in the 10% RS + HF group. PCR results suggested that the high-fat diet could highly significantly reduce the number of gut Bifidobacteria (P < 0.01), which, however, was very significantly increased by supplementation of 10% and 15% RS (P < 0.001). Hence, we concluded that resistant starch can restore the diversity of gut Actinobacteria in obese mice, and significantly promote the growth of Bifidobacteria in a dose-dependent manner.