Abstract：
Metabolic disorders pose significant challenges in transition dairy cows. Numerous parameters have been investigated in this context, and apelin has recently emerged as a potential metabolic indicator. Accordingly, this study aimed to assess the associations between this hormone and other metabolic parameters. Twenty-two adult Holstein-Friesian dairy cows, 21 days before their expected calving date, were selected for blood sampling and serum separation at four time points: 21 and 10 days before calving and 10 and 21 days after parturition. Serum concentrations of apelin, leptin, insulin, cortisol, T3, T4, non-esterified fatty acids, glucose, total protein, albumin, globulin, aspartate aminotransferase, alanine transaminase, triglycerides, cholesterol, high, low and very low-density lipoproteins, total, direct and indirect bilirubin were measured in these samples. Surrogate indices for insulin resistance, body condition score, and milk production were also evaluated. Throughout the transition period, a significant increase in apelin levels was observed. Various models were employed to identify associations between apelin and the studied metabolic parameters. Notably, significant correlations between apelin and Leptin, Insulin, Cortisol, T3, T4, NEFA, Cholesterol, LDL, VLDL, Total Protein, Albumin, Globulin, Total Bilirubin, Direct Bilirubin and Indirect Bilirubin were observed, with some being immediate while others developed over time. These findings indicate a mutual influence between apelin and specific metabolic indices. Changes in any component of the metabolic profile at one stage can lead to alterations in apelin levels in subsequent stages. The correlations uncovered between apelin and other components of the metabolic profile in transitioning dairy cows offer valuable insights, contributing to a better understanding of the potential effects of apelin on the studied indicators and vice versa.
摘要：
代谢紊乱对转型奶牛构成重大挑战。在这种情况下，已经研究了许多参数，和apelin最近已成为潜在的代谢指标。因此，本研究旨在评估该激素与其他代谢参数之间的关联.22头成年荷斯坦-弗里斯奶牛，在他们的预期产卵日期前21天，选择在四个时间点进行血液采样和血清分离：产卵前21天和10天以及分娩后10天和21天。apelin的血清浓度,瘦素,胰岛素，皮质醇,T3，T4，非酯化脂肪酸，葡萄糖，总蛋白质，白蛋白,球蛋白,天冬氨酸转氨酶,丙氨酸转氨酶，甘油三酯，胆固醇,高,低密度和极低密度脂蛋白，total,在这些样本中测量直接和间接胆红素。胰岛素抵抗的替代指数，身体状况评分,和牛奶产量也进行了评估。在整个过渡期内,观察到apelin水平显着增加。采用各种模型来鉴定Apelin与所研究的代谢参数之间的关联。值得注意的是,apelin和瘦素之间存在显著相关性，胰岛素,皮质醇,T3、T4、NEFA、胆固醇,LDL,VLDL,总蛋白质,白蛋白,球蛋白,总胆红素,观察到直接胆红素和间接胆红素，有些是即时的，而另一些是随着时间的推移而发展的。这些发现表明apelin与特定代谢指标之间存在相互影响。在一个阶段代谢谱的任何组分的变化可导致随后阶段中的apelin水平的改变。在过渡奶牛中发现的apelin与代谢谱的其他成分之间的相关性提供了有价值的见解，有助于更好地了解apelin对所研究指标的潜在影响，反之亦然。
