6种多糖体外酵解特性的比较

Comparative Study on the in vitro Fermentation Characteristics of Six Polysaccharides

为研究6种结构不同的多糖阿拉伯胶(gum arabic,GA)、山楂果胶(hawthorn pectin,HP)、阿拉伯木聚糖(arabinoxylan,AX)、瓜尔豆胶(guar gum,GG)、铁皮石斛多糖(Dendrobium officinale polysaccharides,DOP)和燕麦β-葡聚糖(oatβ-glucan,OG)在相同初始肠道菌群下酵解特性的差异。以猪结肠消化物作为接种物,在厌氧条件下酵解0、12、24、48 h,测定短链脂肪酸(short-chain fatty acids,SCFAs)和肠道菌群的变化。SCFAs变化结果表明,6种多糖产生的SCFAs均以乙酸、丙酸和丁酸为主;其中,阿拉伯胶产生丙酸的能力较强,铁皮石斛多糖和燕麦β-葡聚糖产生的乙酸和丁酸含量较高,且总SCFAs含量较高,山楂果胶产生的总SCFAs的含量较低。肠道菌群结果分析表明,厚壁菌门、拟杆菌门和变形菌门为酵解过程中的优势菌门。在属水平上,6种多糖对不同属的菌群促进作用不同,阿拉伯胶可以促进布劳特氏菌属的增殖,其余5种多糖均能促进益生菌属乳杆菌属的增殖,且燕麦β-葡聚糖中乳杆菌属的丰度最高,其次是阿拉伯木聚糖和铁皮石斛多糖。综合来看,铁皮石斛多糖和燕麦β-葡聚糖的酵解特性较好。

The differences in fermentation characteristics of six polysaccharides with unique structures,including gum arabic(GA),hawthorn pectin(HP),arabinoxylan(AX),guar gum(GG),Dendrobium officinale polysaccharide(DOP),and oatβ-glucan(OG),exposed to the same initial gut microbiota were studied.Using the digesta of porcine colon as inoculum,the changes to short-chain fatty acids(SCFAs)as well as the gut microbiota were determined after 0,12,24 h and 48 h of fermentation under anaerobic conditions.Resultingly,acetic acid,propionic acid,and butyric acid were the main SCFAs produced through fermentation of the six polysaccharides.Specifically,gum arabic had a strong ability to promote propionic acid production,while D.officinale polysaccharide and oatβ-glucan promoted high acetic acid and butyric acid production.Additionally,D.officinale polysaccharide and oatβ-glucan produced highest total SCFAs,while hawthorn pectin produced the lowest.Analysis of the gut microbiota showed that Firmicutes,Bacteroidetes,and Proteobacteria were the dominant bacteria involved in the process of fermentation.At the genus level,the six polysaccharides had various promoting effects on different genera.Gum arabic promoted the proliferation of Blautia,while the other five polysaccharides promoted the proliferation of Lactobacillus.Notably,the abundance of Lactobacillus was the highest after fermentation of oatβ-glucan,followed by that of arabinoxylan and D.officinale polysaccharide.In general,D.officinale polysaccharide and oatβ-glucan showed the best fermentation characteristics.