UCD School of Agriculture, Food Science and Veterinary Medicine, College of Life Sciences, University College Dublin, Belfield, Dublin, Ireland.
Physiol Genomics. 2011 Jan 7;43(1):12-23. doi: 10.1152/physiolgenomics.00213.2009. Epub 2010 Oct 5.
Our objective was to evaluate the effects of phenotypic ranking on residual feed intake (RFI) on the transcription of genes 1) involved in the respiratory chain complex and 2) coding for transcriptional factors regulating mitochondrial biogenesis, across two contrasting diet types. Beef heifers (n = 86) fed a diet comprising 70:30 concentrate-corn silage [low forage (LF)] over a 82-day period were ranked on RFI. The 10 highest (feed inefficient, high-RFI) and 10 lowest (feed efficient, low-RFI) ranking animals were selected for the current study. Biopsies of the M. longissimus dorsi were harvested following initial selection (LF diet) and again following a 6 wk period while the animals were offered a high-forage (HF) grass silage-only diet. Real-time PCR was used to quantify mRNA transcripts of 17 genes associated with cellular energetic efficiency. The mRNA expression of UCP3 tended to be upregulated (2.2-fold, P = 0.06) for the high-RFI compared with the low-RFI animals. mRNA transcripts coding for the transcription factor PGC-1α was 1.7-fold higher (P = 0.01) in low compared with high-RFI animals. A phenotype × diet interaction was evident for the abundance of ANT1 mRNA transcript, with greater (P = 0.04) expression levels detected in the low-RFI phenotype during the HF period, but no difference (P = 0.50) between phenotypes during the LF period. A phenotype × diet interaction was also evident for COX II with greater expression levels detected (P = 0.04) in the low compared with the high RFI phenotype while on LF but not the HF diet (P = 0.22). These data suggest an association between cellular energetic efficiency and RFI in cattle.
我们的目的是评估表型评分对剩余采食量（RFI）的影响，这种影响表现在以下两个方面：1）与呼吸链复合物相关的基因的转录，2）编码调节线粒体生物发生的转录因子的基因的转录。该研究横跨两种截然不同的饲料类型。82 天内，给饲喂包含 70：30 浓缩物-玉米青贮料（低纤维饲粮，LF）的肉牛小母牛（n = 86）进行 RFI 表型评分。根据排名，选择前 10 名（饲料效率低、高 RFI）和后 10 名（饲料效率高、低 RFI）的动物进行当前研究。最初选择（LF 饲粮）和动物接受高纤维饲粮（HF 牧草青贮料）6 周后，对背最长肌的活检组织进行了取样。实时 PCR 用于定量与细胞能量效率相关的 17 个基因的 mRNA 转录本。与低 RFI 动物相比，高 RFI 动物的 UCP3 基因 mRNA 表达有上调趋势（2.2 倍，P = 0.06）。与低 RFI 动物相比，PGC-1α 转录因子的 mRNA 转录本高 1.7 倍（P = 0.01）。在 ANT1 mRNA 转录本的丰度上，表现出表型 × 饲粮的互作，在 HF 期，低 RFI 表型的表达水平更高（P = 0.04），而 LF 期的表型之间没有差异（P = 0.50）。COX II 也表现出表型 × 饲粮的互作，LF 饲粮时，低 RFI 表型的表达水平更高（P = 0.04），而 HF 饲粮时则没有差异（P = 0.22）。这些数据表明，在牛中，细胞能量效率与 RFI 之间存在关联。
