Bacterial communities in the rumen of Holstein heifers differ when fed orchardgrass as pasture vs. hay.
Bacterial communities in the rumen of Holstein heifers differ when fed orchardgrass as pasture vs. hay.
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DOI：
10.3389/fmicb.2014.00689
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发表时间：
2014
影响因子：
5.2
通讯作者：
Weimer PJ
中科院分区：
文献类型：
--
作者：
Mohammed R;Brink GE;Stevenson DM;Neumann AP;Beauchemin KA;Suen G;Weimer PJ
瘤胃中丰富多样的微生物群为反刍动物提供了利用高纤维性饲料作为能量来源的能力，但令人惊讶的是，尽管这种农业生产系统在世界范围内很重要，但关于饲喂全草料饲料的反刍动物微生物群组成的信息却很少。在3个28天的周期内，3头瘤胃放养的荷斯坦小母牛依次放牧果园草牧场（OP），然后喂食果园草干草（OH），然后返回牧场。这些小母牛的瘤胃细菌群落组成的变化（通过自动核糖体基因间间隔分析和16S rRNA基因的高温标记测序确定）比其他2头在相同牧场上维持84 d的小母牛更大。定量PCR结果表明，普雷沃氏菌属成员的16S rRNA基因拷贝数平均为23%，远低于之前报道的全混合饲料奶牛的水平。尽管总化学成分相似，但在OP和OH之间观察到细菌群落组成和瘤胃挥发性脂肪酸（VFA）谱的差异。与OP相比，饲喂OH提高了瘤胃乙酸摩尔比例（P = 0.02），降低了瘤胃丁酸比例（P < 0.01）、支链VFA比例（P < 0.01）和丰富的丁酸弧菌属的相对种群规模（P < 0.001）。尽管所检测的动物数量较少，但观察到的奶牛瘤胃VFA谱的变化与丁酸弧菌丰度的变化以及其作为发酵碳水化合物和蛋白质的丁酸生产者的已知生理学是一致的。
The rich and diverse microbiota of the rumen provides ruminant animals the capacity to utilize highly fibrous feedstuffs as their energy source, but there is surprisingly little information on the composition of the microbiome of ruminants fed all-forage diets, despite the importance of such agricultural production systems worldwide. In three 28-day periods, three ruminally-cannulated Holstein heifers sequentially grazed orchardgrass pasture (OP), then were fed orchardgrass hay (OH), then returned to OP. These heifers displayed greater shifts in ruminal bacterial community composition (determined by automated ribosomal intergenic spacer analysis and by pyrotag sequencing of 16S rRNA genes) than did two other heifers maintained 84 d on the same OP. Phyla Firmicutes and Bacteroidetes dominated all ruminal samples, and quantitative PCR indicated that members of the genus Prevotella averaged 23% of the 16S rRNA gene copies, well below levels previously reported with cows fed total mixed rations. Differences in bacterial community composition and ruminal volatile fatty acid (VFA) profiles were observed between the OP and OH despite similarities in gross chemical composition. Compared to OP, feeding OH increased the molar proportion of ruminal acetate (P = 0.02) and decreased the proportion of ruminal butyrate (P < 0.01), branched-chain VFA (P < 0.01) and the relative population size of the abundant genus Butyrivibrio (P < 0.001), as determined by pyrotag sequencing. Despite the low numbers of animals examined, the observed changes in VFA profile in the rumens of heifers on OP vs. OH are consistent with the shifts in Butyrivibrio abundance and its known physiology as a butyrate producer that ferments both carbohydrates and proteins.