A greater understanding of the rumen microbiota and its function may help find new strategies to improve feed efficiency in cattle. This study aimed to investigate whether the cattle breed affects specific ruminal taxonomic microbial groups and functions associated with feed conversion ratio (FCR), using two genetically related Angus breeds as a model. Total RNA was extracted from 24 rumen content samples collected from purebred Black and Red Angus bulls fed the same forage diet and then subjected to metatranscriptomic analysis. Multivariate discriminant analysis (sparse partial least square discriminant analysis (sPLS-DA)) and analysis of composition of microbiomes were conducted to identify microbial signatures characterizing Black and Red Angus cattle. Our analyses revealed relationships among bacterial signatures, host breeds and FCR. Although Black and Red Angus are genetically similar, sPLS-DA detected 25 bacterial species and 10 functions that differentiated the rumen microbial signatures between those two breeds. In Black Angus, we identified bacterial taxa Chitinophaga pinensis, Clostridium stercorarium and microbial functions with large and small subunits ribosomal proteins L16 and S7 exhibiting a higher abundance in the rumen microbiome. In Red Angus, nonetheless, we identified the poorly characterized bacterial taxon Oscillibacter valericigenes with a higher abundance and pathways related to carbohydrate metabolism. Analysis of composition of microbiomes revealed that C. pinensis and C. stercorarium exhibited a higher abundance in Black Angus compared to Red Angus associated with FCR, suggesting that these bacterial species may play a key role in the feed conversion efficiency of forage-fed bulls. This study highlights how the discovery of signatures of bacterial taxa and their functions can be used to harness the full potential of the rumen microbiome in Angus cattle.

中文翻译：

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使用元转录组学进行分类和功能评估揭示了安格斯牛对瘤胃微生物特征的影响。

对瘤胃微生物群及其功能的更多了解可能有助于寻找提高牛饲料效率的新策略。这项研究的目的是使用两个与遗传相关的安格斯品种作为模型，研究该牛品种是否影响特定的瘤胃生物分类微生物群和与饲料转化率（FCR）相关的功能。从24份瘤胃含量样品中提取总RNA，这些样品取自饲喂相同饲料的纯种黑和红安格斯公牛，然后进行转录组分析。进行了多变量判别分析（稀疏偏最小二乘判别分析（sPLS-DA））和微生物群组成分析，以鉴定表征黑和红安格斯牛的微生物特征。我们的分析揭示了细菌特征，宿主品种和FCR之间的关系。尽管黑安格斯和红安格斯在基因上相似，但sPLS-DA检测到25种细菌和10种功能，可区分这两个品种的瘤胃微生物特征。在黑安格斯，我们确定了细菌类群Chitinophaga pinensis，梭状芽胞杆菌和具有大而小的亚基核糖体蛋白L16和S7的微生物功能，在瘤胃微生物组中表现出更高的丰度。尽管如此，在红安格斯，我们鉴定出了特征性较差的细菌分类群，具有较高的丰度和与碳水化合物代谢有关的途径的产气链球菌。对微生物群组成的分析表明，与FCR相关的红安格斯相比，黑安格斯中的梭状芽胞杆菌和固醇梭菌显示出更高的丰度，这表明这些细菌物种可能在饲草公牛的饲料转化效率中发挥关键作用。这项研究强调了如何利用细菌类群的特征及其功能来充分利用安格斯牛瘤胃微生物组的全部潜能。