笼养鸳鸯肠道微生物组成及其肠道疾病诱因的探讨

Gut Microbiota and Their Possible Correlation to Enteritis in Captive Aix galericulata

肠道微生物能够调节动物机体的物质与能量代谢,参与免疫和疾病预防,对于维持动物的正常生理活动至关重要。本研究基于16S rRNA高通量测序,对患肠炎病和健康群组鸳鸯(Aix galericulata)的肠道微生物进行对比,尝试揭示鸳鸯肠炎可能的致病菌。鸳鸯肠道微生物共鉴定出2020个相似度97%的操作分类单元(OTU)。健康组和肠炎组共同的OTU数量为564个。健康组鸳鸯的微生物Alpha多样性指数与肠炎组之间无显著差异(Mann Whitney U test,P>0.05)。在门水平,鸳鸯的肠道微生物组成以厚壁菌门(Firmicutes)(73.46%)、拟杆菌门(Bacteroidetes)(11.15%)和变形菌门(Proteobacteria)(8.72%)为主。在属水平,丰度最高的类别主要包括狭义梭菌属(Clostridium sensu stricto 1)(29.65%)、库特氏菌属(Kurthia)(24.74%)和乳杆菌属(Lactobacillus)(12.40%)。健康组和肠炎组鸳鸯肠道微生物组成存在显著差异(Adonis,F=3.6087,P<0.05)。在肠炎组中共筛选出25个相对丰度显著高于健康组的类别,其中,狭义梭菌属、埃希氏志贺菌属(Escherichia-Shigella)和脱硫菌属(Desulfovibrio)的相对丰度最高(线性判别分析LDA值>5,P<0.05),这3个属的致病菌可能造成肠道微生物群落失衡,机体免疫力下降,是诱发鸳鸯肠炎的重要因素。

Gut microbiota regulate the material and energy metabolism of organism and participate in immunity and disease prevention,which is helpful to maintain the normal physiological activities of animals.Aix galericulata was selected to explore the possible mechanism of microbiota-inducing enteritis in birds.Two scientific questions were concerned:1)which(several)bacteria may induce enteritis in A.galericulata?What kind of pathogenic mechanism may cause enteritis in A.galericulata?High-throughput sequencing was utilized to analyze the gut microbiota of both healthy animals and those with enteritis,and comparisons were carried out on the diversity and composition between the two groups.A total of 202097%operational taxon units(OTUs)were identified from the gut microbiota of A.galericulata.The number of common OTUs in healthy group and enteritis group was 564(Fig.2).The alpha diversity index of healthy group was higher than that of enteritis group,but without significance(P>0.05).At phylum level,Firmicutes(73.46%),Bacteroidetes(11.15%)and Proteobacteria(8.72%)were the main compositions of the gut microbiota in A.galericulata(Fig.3).At genus level,Kurthia(24.74%)and Lactococcus(8.47%)were the most abundant taxa in healthy group,and Clostridium sensu stricto 1(29.65%)and Lactobacillus(12.40%)were main components in enteritis group.There is significant difference in gut compositions between healthy group and enteritis group(P<0.05).In the enteritis group,a total of 25 microbial classifications were found significantly higher than those of healthy group.Among them,Clostridium_sensu_stricto_1,Escherichia-Shigella and Desulfovibrio bacteria are the most abundant(liner dicriminant analysis value>5,P<0.05)(Fig.6).Clostridiales,Desulfovibrionaceae and Bacillales play important function in the gut of A.galericulata(Fig.7).The conclusion is that the high contents of Clostridium_sensu_stricto_1,Escherichia-Shigella and Desulfovibrio may destroy the balance of intestinal microbial community,cause the decline of immunity,and then serve as important factors inducing the enteritis of A.galericulata.