Jin Wei, Wang Ying, Li Yuanfei, Cheng Yanfen, Zhu Weiyun
Jiangsu Province Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, 210095, Nanjing, China.
Jiangsu Province Key Laboratory of Gastrointestinal Nutrition and Animal Health, Laboratory of Gastrointestinal Microbiology, College of Animal Science and Technology, Nanjing Agricultural University, 210095, Nanjing, China.
Anaerobe. 2018 Apr;50:1-8. doi: 10.1016/j.anaerobe.2018.01.004. Epub 2018 Jan 10.
This study used Miseq pyrosequencing and scanning electron microscopy to investigate the temporal changes in the bacterial community tightly attached to wheat straw in the cow rumen. The wheat straw was incubated in the rumens and samples were recovered at various times. The wheat straw degradation exhibited three phases: the first degradation phase occurred within 0.5 h, and the second degradation phase occurred after 6 h, with a stalling phase occurring between 0.5 and 6 h. Scanning electron microscopy revealed the colonization of the microorganisms on the wheat straw over time. The bacterial communities at 0.5, 6, 24, and 72 h were determined, corresponding to the degradation phases. Firmicutes and Bacteroidetes were the two most dominant phyla in the bacterial communities at the four time points. Principal coordinate analysis (PCoA) showed that the bacterial communities at the four time points were distinct from each other. The wheat straw-associated bacteria stabilized at the phylum level after 0.5 h of rumen incubation, and only modest phylum-level and family-level changes were observed for most taxa between 0.5 h and 72 h. The relative abundance of the dominant genera, Butyrivibrio, Coprococcus, Ruminococcus, Succiniclasticum, Clostridium, Prevotella, YRC22, CF231, and Treponema, changed significantly over time (P < .05). However, at the genus level, unclassified taxa accounted for 70.3% ± 6.1% of the relative abundance, indicating their probable importance in the degradation of wheat straw as well as in the temporal changes of the bacterial community. Thus, understanding the function of these unclassified taxa is of great importance for targeted improvement of forage use efficiency in ruminants. Collectively, our results revealed distinct degradation phases of wheat straw and corresponding changes in the colonized bacterial community.
本研究采用Miseq焦磷酸测序和扫描电子显微镜来研究紧密附着于奶牛瘤胃中小麦秸秆上细菌群落的时间变化。将小麦秸秆置于瘤胃中进行培养，并在不同时间点采集样本。小麦秸秆的降解呈现三个阶段：第一个降解阶段发生在0.5小时内，第二个降解阶段发生在6小时后，在0.5至6小时之间存在一个停滞阶段。扫描电子显微镜显示了微生物随时间在小麦秸秆上的定殖情况。测定了与降解阶段相对应的0.5、6、24和72小时的细菌群落。厚壁菌门和拟杆菌门是这四个时间点细菌群落中最主要的两个门。主坐标分析（PCoA）表明，这四个时间点的细菌群落彼此不同。瘤胃培养0.5小时后，与小麦秸秆相关的细菌在门水平上趋于稳定，在0.5小时至72小时之间，大多数分类群在门水平和科水平上仅观察到适度的变化。优势属丁酸弧菌属、粪球菌属、瘤胃球菌属、琥珀酸分解菌属、梭菌属、普雷沃氏菌属、YRC22、CF231和密螺旋体属的相对丰度随时间发生显著变化（P < 0.05）。然而，在属水平上，未分类的分类群占相对丰度的70.3% ± 6.1%，表明它们在小麦秸秆降解以及细菌群落的时间变化中可能具有重要作用。因此，了解这些未分类分类群的功能对于有针对性地提高反刍动物饲料利用效率具有重要意义。总体而言，我们的结果揭示了小麦秸秆不同的降解阶段以及定殖细菌群落的相应变化。
