Noel Samantha J, Attwood Graeme T, Rakonjac Jasna, Moon Christina D, Waghorn Garry C, Janssen Peter H
Grasslands Research Centre, AgResearch Limited, Palmerston North, New Zealand.
Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand.
PLoS One. 2017 Mar 15;12(3):e0173819. doi: 10.1371/journal.pone.0173819. eCollection 2017.
The complex microbiota that resides within the rumen is responsible for the break-down of plant fibre. The bacteria that attach to ingested plant matter within the rumen are thought to be responsible for initial fibre degradation. Most studies examining the ecology of this important microbiome only offer a 'snapshot' in time. We monitored the diversity of rumen bacteria in four New Zealand dairy cows, grazing a rye-grass and clover pasture over five consecutive seasons, using high throughput pyrosequencing of bacterial 16S rRNA genes. We chose to focus on the digesta-adherent bacterial community to learn more about the stability of this community over time. 16S rRNA gene sequencing showed a high level of bacterial diversity, totalling 1539 operational taxonomic units (OTUs, grouped at 96% sequence similarity) across all samples, and ranging from 653 to 926 OTUs per individual sample. The nutritive composition of the pasture changed with the seasons as did the production phase of the animals. Sequence analysis showed that, overall, the bacterial communities were broadly similar between the individual animals. The adherent bacterial community was strongly dominated by members of Firmicutes (82.1%), followed by Bacteroidetes (11.8%). This community differed between the seasons, returning to close to that observed in the same season one year later. These seasonal differences were only small, but were statistically significant (p < 0.001), and were probably due to the seasonal differences in the diet. These results demonstrate a general invariability of the ruminal bacterial community structure in these grazing dairy cattle.
瘤胃内存在的复杂微生物群负责植物纤维的分解。附着在瘤胃内摄入植物物质上的细菌被认为是最初纤维降解的原因。大多数研究这个重要微生物群落生态学的研究仅提供了某个时间点的“快照”。我们使用细菌16S rRNA基因的高通量焦磷酸测序技术，对四头新西兰奶牛瘤胃细菌的多样性进行了监测，这些奶牛在五个连续季节里放牧黑麦草和三叶草牧场。我们选择专注于与食糜附着的细菌群落，以更多地了解这个群落随时间的稳定性。16S rRNA基因测序显示细菌多样性水平很高，所有样本中共有1539个操作分类单元（OTU，按96%的序列相似性分组），每个个体样本的OTU数量从653到926不等。牧场的营养成分随季节变化，动物的生产阶段也如此。序列分析表明，总体而言，个体动物之间的细菌群落大致相似。附着细菌群落以厚壁菌门成员为主（82.1%），其次是拟杆菌门（11.8%）。这个群落随季节不同而有所差异，一年后又恢复到接近同一季节观察到的情况。这些季节差异虽小，但具有统计学意义（p < 0.001），可能是由于饮食的季节差异造成的。这些结果表明，这些放牧奶牛瘤胃细菌群落结构总体上具有稳定性。
