番鸭盲肠不同肠型特征及其与盲肠短链脂肪酸含量、屠宰性能的相关性研究

Study on Different Characteristics of Cecal Enterotypes and Their Association with Cecal Short-Chain Fatty Acid Contents and Slaughter Performance of Muscovy Ducks

本试验旨在研究番鸭盲肠不同肠型特征及其与盲肠短链脂肪酸(SCFAs)含量和屠宰性能的关系。通过16S rRNA基因高通量测序,使用PAM算法将200只70日龄的番鸭盲肠菌群进行分型,测定不同肠型番鸭的生长性能、屠宰性能和盲肠中短链脂肪酸含量,在门和属水平上对不同肠型番鸭盲肠菌群结构和多样性进行分析,并对不同肠型番鸭盲肠差异菌属相对丰度与SCFAs含量的关系进行分析。结果显示:番鸭盲肠菌群分为2个肠型:以副拟杆菌属(Parabacteroides)为代表的肠型1(ET1)(n=165)和以梭杆菌属(Fusobacterium)为代表的肠型2(ET2)(n=35)。ET1番鸭盲肠菌群的Shannon指数显著高于ET2番鸭(P<0.05)。在属水平上,ET1番鸭盲肠菌群中拟杆菌属(Bacteroides)(29.33%)、未培养的瘤胃球菌科(Ruminococcaceae_uncultured)(4.83%)和副拟杆菌属(4.68%)的相对丰度较高;ET2番鸭盲肠菌群中拟杆菌属(20.71%)、梭杆菌属(14.56%)和副拟杆菌属(4.29%)的相对丰度较高。通过线性判别分析效应大小(LEfSe)比较分析发现,不同肠型之间的差异菌属包括粪杆菌属(Faecalibacterium)、丁酸球菌属(Butyricicoccus)和霍氏真杆菌群([Eubacterium]hallii group)等产丁酸菌。比较不同肠型番鸭盲肠中的短链脂肪酸含量发现,ET1番鸭盲肠中乙酸、丙酸和丁酸含量显著高于ET2番鸭(P<0.05),而ET1和ET2番鸭盲肠中异丁酸、戊酸和异戊酸含量均无显著差异(P>0.05)。进一步将ET1和ET2番鸭盲肠差异菌属相对丰度与短链脂肪酸含量进行Spearman相关性分析发现,粪杆菌属相对丰度与丙酸、丁酸、异丁酸、戊酸、异戊酸含量均表现出显著正相关(P<0.05)。此外,比较不同肠型番鸭的屠宰性能发现,ET2番鸭的腹脂重和腹脂率显著高于ET1番鸭(P<0.05),而在屠体重、全净膛重、半净膛重、屠宰率、全净膛率、半净膛率、胸肌重、腿肌重、胸肌率和腿肌率方面ET1和ET2番鸭均无显著差异(P>0.05)。由此可见,不同肠型番鸭盲肠菌群结构的差异可能造成其盲肠中短链脂肪酸含量差异,从而进一步对屠宰性能产生一定影响,该结果可为肠道微生物与宿主之间的互作提供新的见解。

The aim of this study was to explore the characteristics of different cecal enterotypes(ETs)and their relationship with cecal short-chain fatty acids(SCFAs)and slaughter performance of Muscovy ducks.Through high-throughput 16S rRNA gene sequencing,cecal enterotypes were identified by the partitioning around medoid(PAM)algorithm from 200 Muscovy ducks at 70 days of age.The growth performance,slaughtering performance and cecal SCFAs contents of Muscovy ducks with different ETs were determined.The structure and diversity of cecal microbiota of Muscovy ducks with different ETs at phylum and genus levels and the relationship between the relative abundance of differential genera and SCFAs content in cecum were also analyzed.The results showed that two ETs were identified from the cecum of Muscovy ducks:ET1(n=165)represented by Parabacteroides and ET2(n=35)represented by Fusobacterium,and the Shannon index of ET1 was significantly higher than that of ET2(P<0.05).At the genus level,the relative abundances of Bacteroides(29.33%),Ruminococcaceae_uncultured(4.83%)and Parabacteroides(4.68%)were higher in ET1 than those in ET2,while the relative abundances of Bacteroides(20.71%),Fusobacterium(14.56%),and Parabacteroides(4.29%)were higher in ET2 than those in ET1.Comparative analysis by linear discriminant analysis effect size(LEfSe)revealed that the differential genera between different ETs included butyric acid-producing bacteria such as Faecalibacterium,Butyricoccus and[Eubacterium]hallii group and so on.Comparison of the SCFAs contents in the cecum of Muscovy ducks with different ETs revealed that the contents of acetate,propionate and butyrate in the cecum of ET1 were significantly higher than those of ET2(P<0.05),whereas the contents of isobutyrate,valerate and isovalerate in the cecum did not show any significant difference between ET1 and ET2(P>0.05).Further Spearman correlation analysis of the relative abundances of differential genera with SCFAs contents revealed significant positive correlations between Faecalibacterium and propionate,butyrate,isobutyrate,valerate and isovalerate(P<0.05).In addition,comparing the slaughtering performance of Muscovy ducks with different ETs,it was found that the abdominal fat weight and the percentage of abdominal fat of ET2 Muscovy ducks were significantly higher than those of ET1 Muscovy ducks(P<0.05),while there were no significant differences in the dressed weight,half-eviscerated weight,eviscerated weight dressed percentage,percentage of half-eviscerated yield,percentage of eviscerated yield,breast muscle weight,leg muscle weight,percentage of breast muscle and percentage of leg muscle(P>0.05).These findings indicate that the difference in cecal microbiota structure between two ETs might result in differences in SCFAs contents in the cecum of Muscovy ducks,which might further influence the slaughter performance.It may provide new insights into the interactions between intestinal microbiota and their hosts.