Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
J Anim Physiol Anim Nutr (Berl). 2012 Feb;96(1):137-47. doi: 10.1111/j.1439-0396.2011.01130.x. Epub 2011 Feb 15.
Dairy cows with high and low plasma non-esterified fatty acid (NEFA) concentrations in early lactation were compared for plasma parameters and mRNA expression of genes in liver and subcutaneous adipose tissue. The study involved 16 multiparous dairy cows with a plasma NEFA concentration of >500 μmol/l [n = 8, high NEFA (HNEFA)] and <140 μmol/l [n = 8, low NEFA (LNEFA)] in the first week post-partum (pp). Blood samples, adipose and liver tissues were collected on day 1 (+1d) and at week 3 pp (+3wk). Blood plasma was assayed for concentrations of metabolites and hormones. Subcutaneous adipose and liver tissues were analysed for mRNA abundance by real-time qRT-PCR encoding parameters related to lipid metabolism. Results showed that mean daily milk yield and milk fat quantity were higher in HNEFA than in LNEFA cows (p < 0.01), and the NEB was more negative in HNEFA than in LNEFA in +3wk too (p < 0.05). HNEFA cows had slightly lower (p < 0.1) insulin concentrations than LNEFA cows across the study period, and the body condition score decreased more from +1d to +3wk in HNEFA than in LNEFA (p = 0.09). The mRNA abundance of genes in the liver related to fatty acid oxidation (carnitine palmitoyltransferase 2 and very long chain acyl-coenzyme A dehydrogenase) and ketogenesis (3-hydroxy-3-methylglutaryl-coenzyme A synthase 2) were lower in HNEFA than in LNEFA cows. No differences between the two groups were observed for mRNA expression of genes in adipose tissue. The number of calculated significant correlation coefficients (moderately strong) between parameters in the liver and in adipose tissue was nearly similar on +1d, and higher for HNEFA compared with LNEFA cows in +3wk. In conclusion, dairy cows with high compared with low plasma NEFA concentrations in early lactation show differentially synchronized mRNA expression of genes in adipose tissue and liver in +3wk that suggests a different orchestrated homeorhetic regulation of lipid metabolism.
高产奶牛和低产奶牛在初乳期的血浆非酯化脂肪酸（NEFA）浓度进行了比较，以研究血浆参数和肝脏及皮下脂肪组织中基因的 mRNA 表达。本研究涉及 16 头经产奶牛，产后第 1 周（pp）的血浆 NEFA 浓度>500 μmol/l[8 头，高 NEFA（HNEFA）]和<140 μmol/l[8 头，低 NEFA（LNEFA）]。在产后第 1 天（+1d）和第 3 周 pp（+3wk）采集血液样本、脂肪和肝脏组织。检测血液血浆代谢物和激素浓度。通过实时 qRT-PCR 分析皮下脂肪和肝脏组织中与脂质代谢相关参数的 mRNA 丰度。结果表明，HNEFA 奶牛的平均日产奶量和乳脂量均高于 LNEFA 奶牛（p<0.01），+3wk 时 HNEFA 的净能也更负（p<0.05）。整个研究期间，HNEFA 奶牛的胰岛素浓度略低（p<0.1），HNEFA 奶牛的体况评分从+1d 到+3wk 下降更多（p=0.09）。与脂肪氧化（肉毒碱棕榈酰转移酶 2 和长链酰基辅酶 A 脱氢酶）和酮生成（3-羟-3-甲基戊二酰辅酶 A 合酶 2）相关的肝脏基因的 mRNA 丰度在 HNEFA 奶牛中低于 LNEFA 奶牛。两组间脂肪组织基因的 mRNA 表达无差异。在+1d，肝脏和脂肪组织参数之间计算的显著相关系数（中等强度）的数量几乎相似，在+3wk 时，HNEFA 奶牛比 LNEFA 奶牛更高。总之，初乳期血浆 NEFA 浓度较高的奶牛与血浆 NEFA 浓度较低的奶牛相比，在+3wk 时肝脏和脂肪组织中基因的 mRNA 表达存在差异同步性，表明脂质代谢的同源调节存在不同的协调。
