摘要
Dietary intake is known to be a driver of microbial community dynamics in ruminants. Beef cattle go through a finishing phase that typically includes very high concentrate ratios in their feed, with consequent effects on rumen metabolism including methane production. This longitudinal study was designed to measure dynamics of the rumen microbial community in response to the introduction of high concentrate diets fed to beef cattle during the finishing period. A cohort of 50 beef steers were fed either of two basal diet formulations consisting of approximately 10:90 or 50:50 forage:concentrate ratios respectively. Nitrate and oil rich supplements were also added either individually or in combination. Digesta samples were taken at time points over ~ 200 days during the finishing period of the cattle to measure the adaptation to the basal diet and long-term stability of the rumen microbiota. 16S rRNA gene amplicon libraries were prepared from 313 rumen digesta samples and analysed at a depth of 20,000 sequences per library. Bray Curtis dissimilarity with analysis of molecular variance (AMOVA) revealed highly significant (p < 0.001) differences in microbiota composition between cattle fed different basal diets, largely driven by reduction of fibre degrading microbial groups and increased relative abundance of an unclassified Gammaproteobacteria OTU in the high concentrate fed animals. Conversely, the forage-based diet was significantly associated with methanogenic archaea. Within basal diet groups, addition of the nitrate and combined supplements had lesser, although still significant, impacts on microbiota dissimilarity compared to pre-treatment time points and controls. Measurements of the response and stability of the microbial community over the time course of the experiment showed continuing adaptation up to 25 days in the high concentrate groups. After this time point, however, no significant variability was detected. High concentrate diets that are typically fed to finishing beef cattle can have a significant effect on the microbial community in the rumen. Inferred metabolic activity of the different microbial communities associated with each of the respective basal diets explained differences in methane and short chain fatty acid production between cattle. Longitudinal sampling revealed that once adapted to a change in diet, the rumen microbial community remains in a relatively stable alternate state.
摘要译文
已知膳食摄入是反刍动物中微生物群落动态的驾驶员。牛肉牛通过整理阶段，通常在其饲料中包括非常高的浓缩率，因此对瘤胃代谢的影响，包括甲烷生产。这种纵向研究旨在测量瘤胃微生物群落的动态，以应对在整理期间引入饲喂牛肉牛的高浓缩饮食。将50个牛肉配方的群组中的两种基础饮食配方中的任何一种组成，分别由大约10:90或50:50饲料组成：浓缩比。还单独或组合添加硝酸盐和耐油补充剂。 Digesta样品在牛的整理期间在〜200天的时间点拍摄，以衡量对瘤胃微生物的基础饮食和长期稳定性的适应。 16S rRNA基因扩增子文库由313克鲁内加麦克酸样品制备，并在每个文库的每个文库中分析20,000个序列。与分子方差分析（AMOVA）分析的BRAY CURTIS差异显着（P <0.001）微生物群组合物在饲喂不同基础饮食之间的微生物群组合物，大部分通过减少纤维降解微生物组和增加的未分类伽血曲杆菌OTU的相对丰度而导致。高浓缩的动物。相反，饲料的饮食与甲状腺原子造成显着相关。在基础饮食群中，添加硝酸盐和组合补充剂的添加虽然仍然显着，但与治疗时间点和对照相比，对微生物群不同的影响。在实验时间过程中，微生物群落的响应和稳定性的测量显示在高浓缩液中最长可适应25天。然而，在此时间点之后，没有检测到显着的可变性。通常馈送到整理牛肉的高浓缩饮食可能对瘤胃中的微生物群落产生显着影响。推断与各自基质饮食相关的不同微生物社区的代谢活性解释了牛之间甲烷和短链脂肪酸产生的差异。纵向抽样显示，曾经适应饮食的变化，瘤胃微生物群落仍处于相对稳定的交替状态。
Timothy J. Snelling; Marc D. Auffret; Carol-Anne Duthie; Robert D. Stewart; Mick Watson; Richard J. Dewhurst; Rainer Roehe;Alan W. Walker. Temporal stability of the rumen microbiota in beef cattle, and response to diet and supplements[J]. Animal Microbiome, 2019,1