Methane Production in Dairy Cows Correlates with Rumen Methanogenic and Bacterial Community Structure.
Methane Production in Dairy Cows Correlates with Rumen Methanogenic and Bacterial Community Structure.
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DOI：
10.3389/fmicb.2017.00226
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发表时间：
2017
影响因子：
5.2
通讯作者：
Bertilsson J
中科院分区：
文献类型：
--
作者：
Danielsson R;Dicksved J;Sun L;Gonda H;Müller B;Schnürer A;Bertilsson J
甲烷（CH4）是瘤胃中饲料发酵的最终产物。尽管饲养条件相同，但甲烷产量因个体而异。为了更好地了解个体差异背后的因素，对73头奶牛进行了研究，这些奶牛给予相同的饲料，但CH4排放量不同，重点是纤维消化，发酵终产物以及细菌和古细菌组成。在总共21头奶牛（12荷斯坦，9瑞典红）确定为持续低，中，高CH4排放超过3个月的时间内，进一步选择瘤胃液中的微生物群落结构分析。这通过对16S rRNA基因的V4区进行测序和通过靶向甲烷短杆菌组的定量qPCR进行评估。结果表明，甲烷排放量低与甲烷短杆菌反刍动物分支丰度高呈正相关。在OTU水平上进行主坐标分析（PCoA），发现与CH4产生相关的细菌有两个明显的类群（P <0.01）。一个簇与低CH4产生相关（称为簇L），而另一个簇与高CH4产生相关（簇H），并且在两个簇中均出现中等发射体。聚类之间的差异主要与属于普雷沃氏菌属的某些OTU的差异丰度有关。此外，属于琥珀弧菌科的几个OTU在属于聚类L的样品中占优势。挥发性脂肪酸的发酵模式表明，L簇中丙酸的比例较高，而H簇中丁酸的比例较高。奶牛之间的产奶量或有机物消化率没有差异。与集群H中的奶牛相比，集群L中的奶牛具有较低的CH4/kg能量校正牛奶（ECM），8.3克CH4/kg ECM，与之相比，9.7克CH4/kg ECM，表明低CH4奶牛利用饲料更有效地进行牛奶生产，这可能表明细菌和古细菌（或产甲烷菌）群体中反映的更有效的微生物群体或宿主遗传差异。
Methane (CH4) is produced as an end product from feed fermentation in the rumen. Yield of CH4 varies between individuals despite identical feeding conditions. To get a better understanding of factors behind the individual variation, 73 dairy cows given the same feed but differing in CH4 emissions were investigated with focus on fiber digestion, fermentation end products and bacterial and archaeal composition. In total 21 cows (12 Holstein, 9 Swedish Red) identified as persistent low, medium or high CH4 emitters over a 3 month period were furthermore chosen for analysis of microbial community structure in rumen fluid. This was assessed by sequencing the V4 region of 16S rRNA gene and by quantitative qPCR of targeted Methanobrevibacter groups. The results showed a positive correlation between low CH4 emitters and higher abundance of Methanobrevibacter ruminantium clade. Principal coordinate analysis (PCoA) on operational taxonomic unit (OTU) level of bacteria showed two distinct clusters (P < 0.01) that were related to CH4 production. One cluster was associated with low CH4 production (referred to as cluster L) whereas the other cluster was associated with high CH4 production (cluster H) and the medium emitters occurred in both clusters. The differences between clusters were primarily linked to differential abundances of certain OTUs belonging to Prevotella. Moreover, several OTUs belonging to the family Succinivibrionaceae were dominant in samples belonging to cluster L. Fermentation pattern of volatile fatty acids showed that proportion of propionate was higher in cluster L, while proportion of butyrate was higher in cluster H. No difference was found in milk production or organic matter digestibility between cows. Cows in cluster L had lower CH4/kg energy corrected milk (ECM) compared to cows in cluster H, 8.3 compared to 9.7 g CH4/kg ECM, showing that low CH4 cows utilized the feed more efficient for milk production which might indicate a more efficient microbial population or host genetic differences that is reflected in bacterial and archaeal (or methanogens) populations.