高脂肪日粮和产甲烷菌抑制剂对C57BL/6J小鼠盲肠微生物及脂肪代谢的影响

Influences of high-fat diet and methanogens inhibitor on the cecal microbiota and fat metabolism in C57BL /6J mice

【目的】本文旨在研究产甲烷菌抑制剂溴氯甲烷(BCM)对采食高、低脂肪水平日粮小鼠的肠道微生物以及脂肪代谢的影响。【方法】选取32只21日龄的雌性C57BL/6J小鼠,随机分成4组:对照低脂日粮组、对照低脂日粮加BCM组、高脂日粮组及高脂日粮加BCM组,每组8个重复,BCM通过饮水添加。饲养周期为6周,试验期结束,采集小鼠血液样品,用于生化指标分析;采集小鼠盲肠内容物,用变性梯度凝胶电泳(DGGE)和real-time PCR技术分析其菌群;气相色谱法分析粪样中短链脂肪酸含量;real-time PCR技术分析肝脏中脂肪代谢相关基因表达。【结果】高脂日粮和BCM处理对小鼠体增重均无显著影响;DGGE图谱中低脂日粮组和高脂日粮组样品聚于不同簇,但对各组总细菌、产甲烷菌和硫还原菌数量无显著影响。高脂日粮组粪样中乙酸占总挥发酸比例显著降低(P<0.05);BCM处理显著增加小鼠粪样丙酸比例(P<0.05);高脂日粮处理显著影响高密度脂蛋白胆固醇、低密度脂蛋白胆固醇和总胆固醇含量(P<0.05);高脂日粮处理促进了甘油三酯水解酶表达(P<0.05)。【结论】高脂日粮对小鼠肠道菌群结构以及脂肪代谢有明显影响,而BCM处理影响较小。

[ Objective] The aim of the study was to investigate the influences of high-fat diet and methanogens inhibitor （bromochloromethane, BCM） on the gut microbiota and fat metabolism in mice. [ Methods] Thirty two female C57BL/6J mice were randomly divided into 4 groups ： fed respectively by Low-fat diet, Low-fat diet ＋ BCM, High-fat diet and High- fat diet ＋ BCM. BCM was administrated through drinking water for six weeks. The body weight of mice was recorded every week. At the end of experiment, the blood was collected for serum biochemical analysis. Bacterial communities in cecal digesta were analyzed by denaturing gradient gel electrophoresis （DGGE） and real-time PCR. VFA （volatile fatty acid） concentrations in feces were determined by gas chromatography. Expressions of fat-related genes in liver were analyzed using real-time PCR. [ Results] DGGE analysis shows that samples from mice fed with high-fat diet gathered together, and separated with samples from low-fat diet group. However, both the fat level in diet and BCM treatment had no effect on the numbers of total bacteria, sulfate reducing bacteria and methanogens. The acetate proportion in feces was significantly decreased （P 〈 0. 05） when fed high-fat diet to mice （P 〈 0. 05）. BCM treatment significantly increased the propionate proportion （P 〈 0.05 ）. High-fat diet also significantly increased the levels of high-density lipoprotein cholesterol （HDL-C）, low-density lipoprotein cholesterol （LDL-C） and total cholesterol （TG） in blood （P 〈 0.05 ）. High-fat diet up-regulated the expression of TGH gene （P 〈 0.05 ）. [ Conclusion ] High-fat diet affected cecal microbiota and fat metabolism of mice, whereas BCM treatment had little effect.