Adaptation Physiology Group, Department of Animal Sciences, Wageningen University and Research, PO Box 338, 6700 AH, Wageningen, the Netherlands.; Laboratory of Biochemistry, Wageningen University and Research, PO Box 338, 6700 AH, Wageningen, the Netherlands.
Laboratory of Biochemistry, Wageningen University and Research, PO Box 338, 6700 AH, Wageningen, the Netherlands.
J Dairy Sci. 2020 May;103(5):4795-4805. doi: 10.3168/jds.2019-17777. Epub 2020 Feb 26.
Negative energy balance in dairy cows in early lactation is related to alteration of metabolic status. However, the relationships among energy balance, metabolic profile in plasma, and metabolic profile in milk have not been reported. In this study our aims were: (1) to reveal the metabolic profiles of plasma and milk by integrating results from nuclear magnetic resonance (NMR) with data from liquid chromatography triple quadrupole mass spectrometry (LC-MS); and (2) to investigate the relationship between energy balance and the metabolic profiles of plasma and milk. For this study 24 individual dairy cows (parity 2.5 ± 0.5; mean ± standard deviation) were studied in lactation wk 2. Body weight (mean ± standard deviation; 627.4 ± 56.4 kg) and milk yield (28.1 ± 6.7 kg/d; mean ± standard deviation) were monitored daily. Milk composition (fat, protein, and lactose) and net energy balance were calculated. Plasma and milk samples were collected and analyzed using LC-MS and NMR. From all plasma metabolites measured, 27 were correlated with energy balance. These plasma metabolites were related to body reserve mobilization from body fat, muscle, and bone; increased blood flow; and gluconeogenesis. From all milk metabolites measured, 30 were correlated with energy balance. These milk metabolites were related to cell apoptosis and cell proliferation. Nine metabolites detected in both plasma and milk were correlated with each other and with energy balance. These metabolites were mainly related to hyperketonemia; β-oxidation of fatty acids; and one-carbon metabolism. The metabolic profiles of plasma and milk provide an in-depth insight into the physiological pathways of dairy cows in negative energy balance in early lactation. In addition to the classical indicators for energy balance (e.g., β-hydroxybutyrate, acetone, and glucose), the current study presents some new metabolites (e.g., glycine in plasma and milk; kynurenine, panthothenate, or arginine in plasma) in lactating dairy cows that are related to energy balance and may be of interest as new indicators for energy balance.
奶牛在泌乳早期的负能量平衡与代谢状态的改变有关。然而，能量平衡、血浆代谢谱和乳代谢谱之间的关系尚未报道。本研究的目的是：（1）通过将核磁共振（NMR）的结果与液相色谱三重四极杆质谱（LC-MS）的数据相结合，揭示血浆和乳的代谢谱；（2）研究能量平衡与血浆和乳代谢谱之间的关系。在这项研究中，我们对 24 头处于泌乳第 2 周的个体奶牛进行了研究。体重（平均值±标准差；627.4±56.4kg）和产奶量（28.1±6.7kg/d；平均值±标准差）每天都有监测。计算乳成分（脂肪、蛋白质和乳糖）和净能量平衡。采集并分析了血浆和乳样，使用 LC-MS 和 NMR。在所有测量的血浆代谢物中，有 27 种与能量平衡相关。这些血浆代谢物与体脂肪、肌肉和骨骼的体储备动员、血流增加和糖异生有关。在所有测量的乳代谢物中，有 30 种与能量平衡相关。这些乳代谢物与细胞凋亡和细胞增殖有关。在血浆和乳中检测到的 9 种代谢物相互之间以及与能量平衡相关。这些代谢物主要与酮血症、脂肪酸β-氧化和一碳代谢有关。血浆和乳的代谢谱深入了解了泌乳早期负能量平衡奶牛的生理途径。除了能量平衡的经典指标（如β-羟丁酸、丙酮和葡萄糖）外，本研究还提出了一些新的代谢物（如血浆和乳中的甘氨酸；血浆中的犬尿氨酸、泛酸或精氨酸）与能量平衡有关，可能是新的能量平衡指标。
