Loor Juan J, Dann Heather M, Guretzky Nicole A Janovick, Everts Robin E, Oliveira Rosane, Green Cheryl A, Litherland Noah B, Rodriguez-Zas Sandra L, Lewin Harris A, Drackley James K
Department of Animal Sciences, University of Illinois, Urbana, Illinois 61801, USA.
Physiol Genomics. 2006 Oct 3;27(1):29-41. doi: 10.1152/physiolgenomics.00036.2006. Epub 2006 Jun 6.
Liver metabolism and health in dairy cows during the periparturient period are affected by plane of nutrition prepartum. Long-term adaptations in hepatic gene expression are important for complete understanding of liver function. We examined temporal gene expression profiles during the dry period and early lactation in liver of Holstein cows fed moderate dietary energy ad libitum or restricted during the entire dry period using a microarray consisting of 7,872 annotated cattle cDNA inserts and quantitative RT-PCR. We identified 85 genes with expression patterns that were affected by level of energy intake prepartum over time. Restricted energy intake prepartum resulted in more pronounced upregulation of genes with key functions in hepatic fatty acid oxidation (CPT1A, ADIPOR2), gluconeogenesis (PC), and cholesterol synthesis (SC4MOL). Ad libitum feeding upregulated a number of genes associated with liver triacylglycerol synthesis (DGAT1) and proinflammatory cytokines (TNFAIP3). Genomic responses to ad libitum feeding were accompanied by increased incorporation of palmitate to esterified products in vitro and increased liver triacylglycerol concentration in vivo. Overall, gene expression profiles due to plane of nutrition prepartum partly explained differences in rates of liver palmitate metabolism, blood serum metabolite concentrations, and liver tissue triacylglycerol concentration. Our data show that moderate overfeeding of energy in the dry period, in the absence of obesity, results in transcriptional changes predisposing cows to fatty liver and perhaps compromising overall liver health during the periparturient period. In this context, controlled energy intake may confer an advantage to the cow by triggering hepatic molecular adaptations well ahead of parturition.
围产期奶牛的肝脏代谢和健康受产前营养水平的影响。肝脏基因表达的长期适应性变化对于全面理解肝脏功能至关重要。我们使用包含7872个已注释牛cDNA插入片段的微阵列和定量RT-PCR技术，研究了在干奶期和泌乳早期，自由采食中等日粮能量或在整个干奶期受限制饲养的荷斯坦奶牛肝脏中的基因表达时间谱。我们鉴定出85个基因，其表达模式随产前能量摄入水平的变化而受到影响。产前能量摄入受限导致在肝脏脂肪酸氧化（CPT1A、ADIPOR2）、糖异生（PC）和胆固醇合成（SC4MOL）中起关键作用的基因出现更明显的上调。自由采食上调了许多与肝脏三酰甘油合成（DGAT1）和促炎细胞因子（TNFAIP3）相关的基因。对自由采食的基因组反应伴随着体外棕榈酸酯化为酯化产物的掺入增加以及体内肝脏三酰甘油浓度升高。总体而言，产前营养水平导致的基因表达谱部分解释了肝脏棕榈酸代谢速率、血清代谢物浓度和肝脏组织三酰甘油浓度的差异。我们的数据表明，在干奶期适度过量饲喂能量（在不存在肥胖的情况下）会导致转录变化，使奶牛易患脂肪肝，并可能在围产期损害整体肝脏健康。在这种情况下，控制能量摄入可能通过在分娩前提前触发肝脏分子适应性变化而使奶牛受益。
