果胶和木聚糖对中华绒螯蟹肠道菌群结构的影响

The Effect of Pectin and Xylan on Intestinal Microflora Structure of Chinese Mitten Crab

本研究旨在揭示果胶和木聚糖对中华绒螯蟹(Eriocheir sinensis)肠道菌群结构的影响。将果胶和麦麸(木聚糖源)分别以8%和30%的比例添加到饲料中制成试验饲料,将经过酶解的果胶和麦麸添加到饲料中制备成对照饲料,饲养初始体重为(5.9依0.4)g的中华绒螯蟹8周。养殖试验结束后,采用16S r DNA荧光定量PCR法分析测定了中华绒螯蟹肠道菌群结构。结果显示中华绒螯蟹肠道细菌主要由变形菌门(Proteobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)、梭杆菌门(Fusobacteria)的细菌组成。果胶组肠道菌群丰度指数Ace和Chao分别低于其对照组31%和39%,肠道菌群多样性指数Simpson比对照组高25%,而Shannon指数比对照组低48%。木聚糖组Ace和Chao指数均比果胶组高约25%,比其酶解对照组高约14%。木聚糖组的多样性指数与其酶解木聚糖组及果胶组的差异较小。上述结果表明,果胶和木聚糖均影响中华绒螯蟹肠道的菌群结构,但两者对肠道菌群丰度的影响不同。

This study aimed to reveal the effects of pectin and xylan on intestinal microflora of Chinese mitten crab. The pectin and wheat bran(xylan source) were included into the test diets at 8% and 30% respectively, while enzymatic hydrolysis pectin and wheat bran were accordingly supplied into control diets. Crabs with an initial weight of(5.9依0.4) g were fed the four test diets for eight weeks. 16 S r DNA specific primers were designed for rapid detection of intestinal microflora structure of Chinese mitten crab by the fluorescence quantitative PCR assay. The results showed Proteobacteria, Firmicutes, Bacteroidetes and Fusobacteria were the main intestinal microflora of Chinese mitten crab. The intestinal microflora abundance index Ace and Chao in group pectin were31% and 39% lower than that of its control group, respectively, while the diversity index Simpson was 25% higher and Shannon was 48% lower than that of its control group. Both index of Ace and Chao of group xylan were 25%higher than group pectin, and was 14% higher than control groups of xylan. The difference of diversity index was small between group xylan and its control group as well as group pectin. These results suggested that the intestinal microflora structure of Chinese mitten crab were affected by both of pectin and xylan, however, the effect of these two non-starch polysaccharides on microflora abundance were different.