摘要
Methane represents an energetic loss, and it has been proposed that its reduction may be associated with improved feed efficiency. Rumen methanogens produce most of the methane. Forty-nine crossbred heifers were individually fed a ration that consisted of 67.75% rolled corn, 20% wet distillers grain with solubles, 8% chopped alfalfa and 4.25% mineral/vitamin/rumensin mix for 84 d. Residual feed intake was the residual of the observed – predicted FI for the multivariate regression of FI on ADG and mid-metabolic BW for the population. Six heifers with the greatest RFI (1.75 ± 0.31 kg DM/d) and 6 with least RFI (-1.48 ± 0.31 kg DM/d) were selected. Rumen fluid was sampled from a tube passed through the mouth into the rumen. Rumen fluid was flash frozen in liquid N2 and stored at -80°C. After the first collection, heifers with greater RFI were pair fed to the less RFI heifers and rumen fluid was sampled 5 wk later. DNA was isolated from the rumen fluid and primer sets targeting total methanogens, Methanomicrobiales, Methanobacteriales, Methanosarcina, Methanobacterium, Methanobrevibacter ruminantium + Mbb. Cuticularis, and Methanobrevibacter smithii + Mbb. wolinii + Mbb. thaueri + Mbb. gottschalkii + Mbb. Woesei were amplified with real-time quantitative PCR (qPCR). Standard curves were generated to quantify copy number. There were no differences in copy number for the interaction of RFI classifications and sample period for all primer sets (P > 0.18). There were no differences in (P > 0.15) in RFI classification for all qPCR primer sets. There were fewer copies for the Methanobrevibacter ruminantium + Mbb. Cuticularis qPCR for samples collected in the first week compared to the 5 wk sample (P = 0.03); however, there were no difference for collection week for the other qPCR assays (P > 0.16). USDA is an equal opportunity provider and employer.
摘要译文
甲烷代表着一个能量损失，已经提出其还原可能与提高的饲料效率有关。瘤胃甲烷生成大部分甲烷。四十九个越野小母牛分别喂食，由67.75％的玉米，20％的湿蒸馏剂谷物组成，带有溶解剂，切碎的苜蓿8％和4.25％的矿物质/维生素/鲁MENENSIN混合物84 d。残留的饲料摄入量是观察到的 - 预测FI在ADG和中代谢BW上的多元回归预测的FI。选择了最大RFI（1.75±0.31 kg dm/d）和6个最小RFI（-1.48±0.31 kg dm/d）的六个小母牛。瘤胃液是从管道穿过嘴进入瘤胃的。瘤胃液在液体N 2中闪烁，并储存在-80°C下。在第一个收藏品之后，将具有更大RFI的小母牛送给了RFI较少的小母牛，并在5周后采样了瘤胃液。将DNA从瘤胃液和底漆集中分离出靶向总甲烷剂，甲烷菌，甲烷杆菌，甲烷核酸菌，甲烷杆菌，甲烷杆菌，甲烷抗逆转录病毒抗乳腺癌 + MBB。 cuticularis和甲烷素史密斯 + MBB。 Wolinii + MBB。 Thaueri + MBB。 Gottschalkii + MBB。用实时定量PCR（QPCR）扩增WOESEI。生成标准曲线以量化拷贝数。 RFI分类的相互作用和所有引物集的样本周期的拷贝数没有差异（p> 0.18）。对于所有QPCR引物集，RFI分类没有差异（p> 0.15）。甲烷抗逆转录病毒抗浓度 + MBB的副本较少。与5周样本相比，第一周收集的样品的表皮QPCR（p = 0.03）；但是，其他QPCR分析的收集周没有差异（p> 0.16）。美国农业部是机会均等的提供者和雇主。
Harvey C Freetly; Am;a K Lindholm-Perry; ;rew P Foote; Sarah Bennett; ; Jim E Wells. 192 Abundance of rumen methanogens did not differ in cattle that differed in residual feed intake[J]. Journal of Animal Science, 2020,98(Sup4)