Department of Animal and Poultry Science, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon S7N5A8, Canada.
J Anim Sci. 2012 Aug;90(8):2476-83. doi: 10.2527/jas.2011-4404. Epub 2012 Feb 3.
A novel SNP was discovered within the promoter region of alcohol dehydrogenase 1C (ADH1C c.-64T>C), the C allele eliminating a potential binding site for the transcription factor C/EPBα. The purpose of this study was to examine if an interaction between this SNP and vitamin A restriction had an effect on carcass characteristics in beef cattle. Following backgrounding on a β-carotene-deficient diet, 130 steers (50 TT, 50 CT, and 30 CC) were finished for 5 mo and received either no supplemental vitamin A (unsupplemented) or 750,000 IU/mo (supplemented). A subgroup of 5 steers • genotype(-1) • treatment(-1) was randomly selected for pre- and postfinishing liver biopsies to assess vitamin A status and measure gene expression. Unsupplemented steers (Bos taurus) had significantly greater (P < 0.05) marbling scores than supplemented steers. There was a significant interaction between genotype and vitamin A supplementation on ether-extractable intramuscular fat (IMF). Within the unsupplemented treatment, TT steers had nearly 23% greater IMF than CC steers. Additionally, unsupplemented TT steers had over 24% greater IMF than supplemented TT steers. Expression of ADH1C in the liver was additive with each additional T allele, potentially due to the elimination of a possible binding site for C/EBPα. It is plausible that CC cattle have reduced ability to metabolize retinol to retinaldehyde (and subsequently retinoic acid) and that a phenotypic effect is only observed when vitamin A is limiting. Therefore, ADH1C c.-64T>C genotype, in combination with reduced vitamin A supplementation, could potentially be implemented in marker-assisted management to maximize marbling in finishing cattle.
一个新的单核苷酸多态性（SNP）被发现在醇脱氢酶 1C（ADH1C c.-64T>C）的启动子区域内，C 等位基因消除了转录因子 C/EPBα 的潜在结合位点。本研究的目的是检验该 SNP 与维生素 A 限制之间的相互作用是否会影响肉牛的胴体特性。在β-胡萝卜素缺乏饮食的育肥阶段后，130 头公牛（50 个 TT、50 个 CT 和 30 个 CC）进行了 5 个月的育肥，并分别接受了不补充维生素 A（未补充）或 750,000IU/月（补充）的处理。从基因型和处理的 5 个亚组中随机选择了 1 个进行育肥前和育肥后的肝脏活检，以评估维生素 A 状态并测量基因表达。未补充维生素 A 的牛（Bos taurus）的大理石花纹评分明显高于补充维生素 A 的牛（P < 0.05）。基因型和维生素 A 补充之间存在显著的互作，对乙醚可提取的肌肉内脂肪（IMF）有影响。在未补充处理中，TT 公牛的 IMF 比 CC 公牛高近 23%。此外，未补充的 TT 公牛的 IMF 比补充的 TT 公牛高 24%以上。肝脏中 ADH1C 的表达与每个额外的 T 等位基因呈加性，这可能是由于 C/EBPα 的可能结合位点被消除了。CC 牛可能具有降低将视黄醇代谢为视黄醛（继而代谢为视黄酸）的能力，并且只有在维生素 A 受到限制时才会观察到表型效应。因此，ADH1C c.-64T>C 基因型，结合减少的维生素 A 补充，可能在标记辅助管理中被实施，以最大限度地提高育肥牛的大理石花纹。
