低分子量酶解灵芝硒多糖对小鼠肠道菌群的影响

Effects of low molecular weight enzymatic hydrolysis of Ganoderma lucidum selenium polysaccharides on intestinal microflora in mice

中文关键词:  灵芝硒多糖  低分子量  肠道菌群  短链脂肪酸  相对丰度

英文关键词:Ganoderma lucidum selenium polysaccharide  low molecular weight  intestinal microbiota  short chain fatty acids  relative abundance

中文摘要:

      目的 研究低分子量灵芝硒多糖对肠道菌群紊乱小鼠的改善调节作用。方法 利用生物发酵法培养富集灵芝硒多糖, 采用热水浸提法提取灵芝硒多糖, 并进一步酶解为低分子量多糖, 以水解率为响应值, 在单因素基础上, 用响应面法优化酶解工艺条件。随后使用超滤膜截取10 kDa以下多糖, 以头孢克肟诱导建立肠道紊乱小鼠模型, 灌胃低分子量灵芝硒多糖, 并测定小鼠体重及肠道内容物短链脂肪酸含量, 利用16S rRNA高通量测序分析小鼠肠道菌群变化。结果 灵芝硒多糖的富硒量为(327±26) mg/g, 多糖含量为(6.14±0.18)%, 低分子量多糖的酶解最优工艺为温度50℃、pH 5.5、时间121 min, 该条件下的水解率为62.8%。研究表明低分子量多糖对小鼠体重无影响, 高通量测序结果显示低分子量灵芝硒多糖能有效改善肠道菌群失调症状, 调节肠道菌群的物种组成, 显著上调厚壁菌门(Firmicutes)丰度, 降低拟杆菌门(Bacteroidetes)丰度, 上调产酸菌乳杆菌属(Lactobacillus)、布劳特氏菌属(Blautia)、链球菌(Streptococcus)、样棒菌属(Allobaculum)、颤螺菌属(Oscillospira)等丰度, 增加乙酸、丁酸含量, 下调普雷沃氏菌(Prevotella)、拟杆菌属(Bacteroides)、梭菌属(Clostridium)、粪球菌属(Coprococcus)、瘤胃球菌属(Ruminococcus)丰度, 抑制丙酸分泌。结论 低分子量灵芝硒多糖具有改善小鼠肠道菌群失调作用, 可能是通过调整菌群组成来影响短链脂肪酸分泌达到保护肠道健康的目的。

英文摘要:

      Objective To study the improving and regulatory effects of low molecular weight Ganoderma lucidum selenium polysaccharide on intestinal microbiota disorder in mice. Methods Selenium polysaccharides of Ganoderma lucidum was cultivated and enriched by biological fermentation, extracted by using hot water extraction method, and further hydrolyzed them into low molecular weight polysaccharides. The hydrolysis rate was taken as the response value, and the enzymatic hydrolysis process conditions were optimized using response surface methodology on a single factor basis. Subsequently, polysaccharides below 10 kDa were extracted using ultrafiltration membranes, and a mouse model of intestinal disorders was established by inducing with cefuroxime. Low molecular weight Ganoderma lucidum selenium polysaccharides were given intragastric administered, and the body weight and short chain fatty acid content of the mouse intestinal contents were measured. The changes in the mouse intestinal microbiota were analyzed using high-throughput 16S rRNA sequencing. Results The selenium content of Ganoderma lucidum polysaccharide was (327±26) mg/g, and the polysaccharide content was (6.14±0.18)%. The optimal enzymatic hydrolysis process for low molecular weight polysaccharides was at a temperature of 50℃, pH of 5.5, and time of 121 minutes. The hydrolysis rate under these conditions was 62.8%. Research had shown that low molecular weight polysaccharides had no effect on the body weight of mice. High throughput sequencing results showed that low molecular weight Ganoderma lucidum selenium polysaccharides could effectively improve symptoms of intestinal microbiota imbalance, regulate the species composition of intestinal microbiota, significantly upregulate Firmicutes abundance, reduce Bacteroides abundance, upregulate the abundance of acid producing bacteria Lactobacillus, Blautia, Streptococcus, Allobaculum, Oscillospira, etc., increase acetic acid and butyric acid content, and downregulate the abundance of Prevotella, Bacteroides, Clostridium, Coprococcus, and Ruminococcus, inhibit propionic acid secretion. Conclusion Low molecular weight Ganoderma lucidum selenium polysaccharide has the effect of improving intestinal microbiota imbalance in mice, which may be achieved by adjusting the composition of the microbiota to affect the secretion of short chain fatty acids and protect intestinal health.