摘要
Ruminal methanogenesis is a microbial fermentive process conducted by methanogens, releasing methane (CH4 ) gas through eruction, and resulting in a dietary energy loss to the host animals and a contribution to greenhouse gas emissions by the agricultural industry. However, the association amongst methanogenic ecology, host feed efficiency, and host enteric CH 4 production is not clear. The overall objective of this research was to investigate the potential linkage among these sectors, and thus four studies were performed. Study 1 and Study 2 were conducted to investigate the correlation between cattle's feed efficiency and methanogenic ecology under growing and finishing diets. The composition of the methanogenic community varied significantly between the two diets, and the associations between methanogenic phylotypes and host's feed efficiency differed between the two diets. When animals were fed growing diet, Methanobrevibacter sp. AbM4 and Methanosphaera stadtmanae were more prevalent in inefficient animals; while under a finishing diet, multiple unidentified species were more common in inefficient animals. In Study 3, the correlation between methanogenic ecology and host CH4 production were studied in dairy cows, and the dietary effect on such correlation was also analyzed. Phylotypes resembling methanogenic archaeon CH1270 and Mbb. gottschalkii strain HO tended to be related to host's CH4 production, but the total methanogen population was not related to the amount of CH4 yield. In Study 4, host effect on ruminal methanogenic community and its adaptation to dietary treatments was examined in beef heifers. The unique microbiota of each animal and the distinctive responses to the dietary treatments within individuals indicate that the animal-to animal variation may be the main cause leading to the inconsistency of host response to dietary or environmental changes. Therefore, individual variation should be taken into account when studying ruminal microbial ecology. In summary, this research revealed that biodiversity of methanognic community rather than then total methanogen density plays an important role in affecting host feed efficiency, determining host's enteric CH 4 production, and adapting to different dietary conditions. Furthermore, host is an essential factor determining its symbiotic relationship with methanogens.
摘要译文
瘤胃甲烷是由甲烷进行的，通过eruction释放甲烷（CH4）气体，并产生一种膳食的能量损失给宿主动物，并通过农业产业的温室气体排放量的贡献微生物fermentive过程。然而，产甲烷生态，主机饲料效率，和主机肠CH 4之间产生的关联并不清楚。这项研究的总体目标是研究这些部门之间的联动潜能，从而四项研究进行。研究1和2的研究进行了下生长肥育饮食调查之间的牛的饲料效率和产甲烷生态环境的关系。产甲烷社区组成的两种饮食之间显著变化，甲烷和种系型和主机的饲料转化率之间的关联的两种饮食之间的差异。当动物喂生长饮食，甲烷短杆菌。AbM4和Methanosphaera stadtmanae是低效的动物更普遍;而下一个整理的饮食，多身份不明的种类为在效率低下的动物更常见。在研究3，产甲烷生态和主机CH4生产之间的关系进行了研究，奶牛，以及此类相关的饮食影响进行了分析。种系型类似甲烷古菌CH1270和MBB。gottschalkii应变何趋向于与主机的甲烷产量，但总产甲烷人口是不相关的甲烷产量的量。在研究4，对瘤胃甲烷社区及其适应饮食治疗效果主机检查牛肉小母牛。每只动物和独特的响应向个人内饮食疗法的独特菌群表明动物到动物变异可能是主要的原因，导致主机响应于饮食或环境变化的不一致性。因此，个体差异应该学习瘤胃微生物生态学时予以考虑。总之，该研究显示，methanognic群落多样性，而不是再总甲烷密度起着影响宿主饲料效率，确定主机的肠溶CH 4产生，并适应不同的膳食条件有重要作用。此外，主机是一个重要的决定因素与产甲烷菌的共生关系。
Zhou, Mi. Rumen Methanogenic Ecology under Different Diets and Cattle Feed Efficiency[D]. CA: University of Alberta (Canada), 2012