College of Animal Science and Technology, Jilin Agricultural University, Changchun, PR China.
Jilin Academy of Agricultural Sciences, Changchun, PR China.
PLoS One. 2019 May 22;14(5):e0214777. doi: 10.1371/journal.pone.0214777. eCollection 2019.
Emission from ruminants has become one of the largest sources of anthropogenic methane emission in China. The structure of the rumen flora has a significant effect on methane production. To establish a more accurate prediction model for methane production, the rumen flora should be one of the most important parameters. The objective of the present study was to investigate the relationship among changes in rumen flora, nutrient levels, and methane production in sheep fed with the diets of different forage-to-concentration ratios, as well as to screen for significantly different dominant genera. Nine rumen-cannulated hybrid sheep were separated into three groups and fed three diets with forage-to-concentration ratios of 50:50, 70:30, and 90:10. Three proportions of the diets were fed according to a 3 × 3 incomplete Latin square, design during three periods of 15d each. The ruminal fluid was collected for real-time polymerase chain reaction (real-time PCR), high-throughput sequencing and in vitro rumen fermentation in a new real-time fermentation system wit. Twenty-two genera were screened, the abundance of which varied linearly with forage-to-concentration ratios and methane production. In addition, during the 12-hour in vitro fermentation, the appearance of peak concentration was delayed by 26-27min with the different structure of rumen bacteria. The fiber-degrading bacteria were positively correlated with this phenomenon, but starch-degrading and protein-degrading bacteria were negative correlated. These results would facilitate macro-control of rumen microorganisms and better management of diets for improved nutrition in ruminants. In addition, our findings would help in screening bacterial genera that are highly correlated with methane production.
反刍动物的排放已成为中国人为甲烷排放的最大来源之一。瘤胃菌群结构对甲烷生成有显著影响。为了建立更准确的甲烷生成预测模型，瘤胃菌群应该是最重要的参数之一。本研究的目的是研究不同饲粮精粗比条件下绵羊瘤胃菌群变化、养分水平与甲烷生成之间的关系，筛选出差异显著的优势菌属。将 9 只瘤胃瘘管杂交绵羊分为 3 组，分别饲喂精粗比为 50:50、70:30 和 90:10 的 3 种饲粮。采用 3×3 不完全拉丁方设计，每个试验期 15d，共 3 个试验期。采集瘤胃液进行实时聚合酶链反应（real-time PCR）、高通量测序和在新型实时发酵系统中的体外瘤胃发酵。筛选出 22 个菌属，其丰度与精粗比和甲烷生成呈线性变化。此外，在 12 小时的体外发酵过程中，不同的瘤胃细菌结构使峰值浓度出现的时间延迟了 26-27min。纤维降解菌与这一现象呈正相关，而淀粉降解菌和蛋白降解菌则呈负相关。这些结果将有助于对瘤胃微生物进行宏观调控，更好地管理饲粮以提高反刍动物的营养水平。此外，我们的研究结果有助于筛选出与甲烷生成高度相关的细菌属。
