Ren Hao, Su Xiaodong, Bai Hanxun, Yang Yuntian, Wang Hongrong, Dan Zeng, Lu Jinbin, Wu Shengru, Cai Chuanjiang, Cao Yangchun, Lei Xinjian, Yao Junhu
College of Animal Science and Technology, Northwest A&F University, Yangling, 712100, Shaanxi, People's Republic of China.
College of Animal Science and Technology, Yangzhou University, Yangzhou, 225009, People's Republic of China.
AMB Express. 2019 Dec 28;9(1):209. doi: 10.1186/s13568-019-0937-8.
Corn grain has a high starch content and is used as main energy source in ruminant diets. Compared with finely ground corn (FGC), steam-flaked corn (SFC) could improve the milk yield of lactating dairy cows and the growth performance of feedlot cattle, but the detailed mechanisms underlying those finding are unknown. The rumen microbiome breaks down feedstuffs into energy substrates for the host animals, and contributes to feed efficiency. Therefore, the current study was conducted to investigate the ruminal bacterial community changes of heifers fed differently processed corn (SFC or FGC) using 16S rRNA sequencing technologies, and to uncover the detailed mechanisms underlying the high performance of ruminants fed the SFC diet. The results revealed that different processing methods changed the rumen characteristics and impacted the composition of the rumen bacteria. The SFC diet resulted in an increased average daily gain in heifers, an increased rumen propionate concentration and a decreased rumen ammonia nitrogen concentration. The relative abundance of the phylum Firmicutes and Proteobacteria were tended to increase or significantly increased in the heifers fed SFC diet compared with FGC diet. In addition, the relative abundance of amylolytic bacteria of the genera Succinivibrio, Roseburia and Blautia were elevated, and the cellulolytic bacteria (Ruminococcaceae_UCG-014 and Ruminococcaceae_UCG-013) were decreased by the steam flaking method. Spearman correlation analysis between the ruminal bacteria and the microbial metabolites showed that the rumen propionate concentration was positively correlated with genera Succinivibrio and Blautia abundance, but negatively correlated with genera Ruminococcaceae_UCG-014 abundance. Evident patterns of efficient improvement in rumen propionate and changes in rumen microbes to further improve feed conversion were identified. This observation uncovers the potential mechanisms underlying the increased efficiency of the SFC processing method for enhancing ruminant performance.
玉米粒淀粉含量高，是反刍动物日粮中的主要能量来源。与细磨玉米（FGC）相比，蒸汽压片玉米（SFC）可提高泌乳奶牛的产奶量和育肥牛的生长性能，但这些发现背后的具体机制尚不清楚。瘤胃微生物群将饲料分解为宿主动物的能量底物，并有助于提高饲料效率。因此，本研究采用16S rRNA测序技术，研究了饲喂不同加工方式玉米（SFC或FGC）的小母牛瘤胃细菌群落变化，以揭示饲喂SFC日粮的反刍动物高性能背后的详细机制。结果表明，不同的加工方法改变了瘤胃特征，影响了瘤胃细菌的组成。SFC日粮使小母牛的平均日增重增加，瘤胃丙酸浓度升高，瘤胃氨氮浓度降低。与FGC日粮相比，饲喂SFC日粮的小母牛中厚壁菌门和变形菌门的相对丰度有增加趋势或显著增加。此外，蒸汽压片法提高了琥珀酸弧菌属、罗斯氏菌属和布劳特氏菌属等淀粉分解菌的相对丰度，而纤维素分解菌（瘤胃球菌科_UCG-014和瘤胃球菌科_UCG-013）减少。瘤胃细菌与微生物代谢产物之间的Spearman相关性分析表明，瘤胃丙酸浓度与琥珀酸弧菌属和布劳特氏菌属丰度呈正相关，但与瘤胃球菌科_UCG-014属丰度呈负相关。确定了瘤胃丙酸有效改善和瘤胃微生物变化以进一步提高饲料转化率的明显模式。这一观察结果揭示了SFC加工方法提高反刍动物生产性能效率提高的潜在机制。
