Wu Xiukun, Zhang Gaosen, Zhang Wei, Zhou Jianwei, Cong Haitao, Yang Guo, Liu Guangxiu
Key Laboratory of Ecological Safety and Sustainable Development in Arid Lands, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou, China.
Key Laboratory of Extreme Environmental Microbial Resources and Engineering, Lanzhou, China.
Front Microbiol. 2024 Jul 24;15:1431063. doi: 10.3389/fmicb.2024.1431063. eCollection 2024.
T-sheep and H-sheep exhibit different environmental adaptability and production performance. The rumen microbiome has co-evolved with hosts and plays a vital role in nutrient digestion and energy metabolism. In our previous study, we found that T-sheep have a higher efficiency in energy metabolism than H-sheep, but the rumen microbial community remains unclear.
In this study, we determined the rumen bacterial profile and rumen fermentation parameters to reveal the bacterial profiles and predictive functions among breeds and diets with four different energy levels, as well as the correlation between bacterial profiles and rumen fermentation characteristics.
The results showed that the rumen total volatile fatty acids (VFAs), acetate, butyrate, total branched-chain VFAs, iso-butyrate, and iso-valerate were higher in T-sheep than H-sheep. The alpha diversity of ruminal bacteria is not affected by dietary energy, but it shows a distinction between the sheep breeds. Specifically, T-sheep rumen bacteria exhibit higher alpha diversity than H-sheep. The beta diversity of ruminal bacteria is not influenced by dietary energy or sheep breeds, indicating similar communities of ruminal bacteria between different diets and sheep breeds. The phyla of Bacteroidetes and Firmicutes predominate in the rumen, with a higher relative abundance of Firmicutes observed in T-sheep than H-sheep. The two most abundant genera in the rumen were 1 and RC9 gut group. 1 is the predominant bacterial genus in the rumen of H-sheep, while the RC9 gut group dominates in the rumen of T-sheep. Microbial co-occurrence network analysis reveals that variations in rumen fermentation characteristics result from differences in module abundance, with a higher abundance of VFA-producing modules observed in the rumen of T-sheep. Microbial function prediction analysis showed that dietary energy rarely alters the functional composition of rumen bacteria. However, there were differences in the functions of rumen bacteria between sheep breeds, with T-sheep showing a greater emphasis on energy metabolism-related functions, while H-sheep showed a greater emphasis on protein metabolism-related functions.
These findings provide evidence of the special rumen microbial community that helps T-sheep efficiently obtain energy from low-protein and low-energy diets, enabling them to survive in the extreme environment of the Qinghai-Tibet Plateau.
T羊和H羊表现出不同的环境适应性和生产性能。瘤胃微生物群与宿主共同进化，在营养消化和能量代谢中起着至关重要的作用。在我们之前的研究中，我们发现T羊在能量代谢方面比H羊效率更高，但瘤胃微生物群落仍不清楚。
在本研究中，我们测定了瘤胃细菌谱和瘤胃发酵参数，以揭示四个不同能量水平的品种和日粮之间的细菌谱和预测功能，以及细菌谱与瘤胃发酵特征之间的相关性。
结果表明，T羊瘤胃中总挥发性脂肪酸（VFA）、乙酸、丁酸、总支链VFA、异丁酸和异戊酸含量高于H羊。瘤胃细菌的α多样性不受日粮能量的影响，但在绵羊品种之间存在差异。具体而言，T羊瘤胃细菌表现出比H羊更高的α多样性。瘤胃细菌的β多样性不受日粮能量或绵羊品种的影响，表明不同日粮和绵羊品种之间瘤胃细菌群落相似。拟杆菌门和厚壁菌门在瘤胃中占主导地位，T羊中厚壁菌门的相对丰度高于H羊。瘤胃中两个最丰富的属是1和RC9肠道菌群。1是H羊瘤胃中的主要细菌属，而RC9肠道菌群在T羊瘤胃中占主导地位。微生物共现网络分析表明，瘤胃发酵特征的差异是由模块丰度的差异引起的，T羊瘤胃中产生VFA的模块丰度更高。微生物功能预测分析表明，日粮能量很少改变瘤胃细菌的功能组成。然而，绵羊品种之间瘤胃细菌的功能存在差异，T羊更强调与能量代谢相关的功能，而H羊更强调与蛋白质代谢相关的功能。
这些发现为特殊的瘤胃微生物群落提供了证据，该群落帮助T羊从低蛋白和低能量日粮中有效获取能量，使其能够在青藏高原的极端环境中生存。
