Zhang Yawei, Li Fuyong, Chen Yanhong, Guan Le-Luo
College of Animal Science, Shanxi Agricultural University, Taiyuan 030031, China.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2P5, Canada.
Animals (Basel). 2022 Aug 3;12(15):1966. doi: 10.3390/ani12151966.
To assess the effects of residual feed intake (RFI) and breed on rumen microbiota, the abundance (DNA) and active population (RNA) of the total bacteria, archaea, protozoa, and fungi in the rumen of 96 beef steers from three different breeds (Angus (AN), Charolais (CH), and Kinsella Composite (KC)), and divergent RFIs (High vs Low), were estimated by measuring their respective maker gene copies using qRT-PCR. All experimental animals were kept under the same feedlot condition and fed with the same high-energy finishing diet. Rumen content samples were collected at slaughter and used for the extraction of genetic material (DNA and RNA) and further analysis. There was a significant difference (p < 0.01) between the marker gene copies detected for abundance and active populations for all four microbial groups. AN steers had a higher abundance of bacteria (p < 0.05) and a lower abundance of eukaryotes (protozoa and fungi, p < 0.05) compared to KC steers, while the abundance of protozoa (p < 0.05) in the AN cattle and fungi (p < 0.05) in the KC cattle were lower and higher, respectively, than those in the CH steers. Meanwhile, the active populations of bacteria, archaea, and protozoa in the KC steers were significantly lower than those in the AN and CH animals (p < 0.01). This work demonstrates that cattle breed can affect rumen microbiota at both the abundance and activity level. The revealed highly active protozoal populations indicate their important role in rumen microbial fermentation under a feedlot diet, which warrants further study.
为评估剩余采食量（RFI）和品种对瘤胃微生物群的影响，通过使用qRT-PCR测量96头来自三个不同品种（安格斯（AN）、夏洛莱（CH）和金塞拉复合品种（KC））且RFI不同（高与低）的肉牛瘤胃中总细菌、古菌、原生动物和真菌的丰度（DNA）和活性种群（RNA）。所有实验动物均饲养在相同的饲养场条件下，并饲喂相同的高能育肥日粮。在屠宰时采集瘤胃内容物样本，用于提取遗传物质（DNA和RNA）并进行进一步分析。所有四个微生物组在丰度和活性种群方面检测到的标记基因拷贝数之间存在显著差异（p < 0.01）。与KC肉牛相比，AN肉牛的细菌丰度更高（p < 0.05），真核生物（原生动物和真菌）丰度更低（p < 0.05），而AN牛的原生动物丰度（p < 0.05）和KC牛的真菌丰度（p < 0.05）分别低于和高于CH肉牛。同时，KC肉牛中细菌、古菌和原生动物的活性种群显著低于AN和CH动物（p < 0.01）。这项工作表明，牛的品种可以在丰度和活性水平上影响瘤胃微生物群。所揭示的高活性原生动物种群表明它们在饲养场日粮条件下瘤胃微生物发酵中发挥着重要作用，这值得进一步研究。
