Marczuk J, Brodzki P, Brodzki A, Kurek Ł
Sub-Department of Internal Diseases of Farm Animals and Horses, Department and Clinic of Animal Internal Medicine, Faculty of Veterinary Medicine, University of Life Science, 20-612 Lublin, Głęboka 30, Poland.
Department and Clinic of Animal Reproduction, Faculty of Veterinary Medicine, University of Life Science, 20-612 Lublin, Głęboka 30, Poland.
Pol J Vet Sci. 2018 Mar;21(1):149-156. doi: 10.24425/119033.
Ketosis is a common condition found in the initial stages of lactation in high-yielding dairy cows. The major cause of ketosis is a negative energy balance. During the energy deficiency, proteolysis processes develop parallel to lipolysis. During proteolysis, muscle tissue can be used as a source of amino acid. To date, the participation of amino acids in gluconeogenesis (glucogenic amino acids) and ketogenesis (ketogenic amino acids) has not been determined in detail. This paper presents the study on determination of the parameters of protein and free amino acid metabolism in blood serum of dairy cows with primary ketosis compared to healthy cows. This study contributes to better understanding of the role of amino acids in pathogenesis of ketosis. A total of 30 cows, divided into two groups: experimental (15 cows with ketosis) and control (15 healthy cows), were included in the study. The concentrations of glucose, β-hydroxybutyrate, total protein, albumin, urea, and free amino acids were determined in peripheral blood. Statistically significantly higher concentrations of glutamine, glutamic acid, isoleucine (p≤0.001), and tyrosine (p≤0.05) were found in cows with primary ketosis compared to healthy cows. Significant decrease in the concentrations of asparagine, histidine, methionine, and serine (p≤0.001), alanine, leucine, lysine and proline (p≤0.05) was observed. Significant increase of total ketogenic and glucogenic amino acids (p≤0.05), and an increased ratio of total ketogenic and glucogenic amino acids to total amino acids (p≤0.001) were noted in cows with ketosis. In our study, the changes, in particular observed in amino acid concentration in cows with primary ketosis, indicate its intensive use in both ketogenesis and gluconeogenesis processes. Therefore, a detailed understanding of the role that amino acids play in gluconeogenesis and ketogenesis will improve ketosis diagnostics and monitoring the course of a ketosis episode. Perhaps, the prevention of this disease is possible by balancing the appropriate feed ration in terms of amino acid content.
酮病是高产奶牛泌乳初期常见的病症。酮病的主要原因是能量负平衡。在能量缺乏期间，蛋白质水解过程与脂肪分解过程同时发生。在蛋白质水解过程中，肌肉组织可作为氨基酸的来源。迄今为止，氨基酸在糖异生（生糖氨基酸）和酮体生成（生酮氨基酸）中的参与情况尚未得到详细确定。本文介绍了与健康奶牛相比，对原发性酮病奶牛血清中蛋白质和游离氨基酸代谢参数进行测定的研究。这项研究有助于更好地理解氨基酸在酮病发病机制中的作用。共有30头奶牛被纳入研究，分为两组：实验组（15头患酮病的奶牛）和对照组（15头健康奶牛）。测定了外周血中葡萄糖、β-羟基丁酸、总蛋白、白蛋白、尿素和游离氨基酸的浓度。与健康奶牛相比，原发性酮病奶牛中谷氨酰胺、谷氨酸、异亮氨酸（p≤0.001）和酪氨酸（p≤0.05）的浓度在统计学上显著更高。观察到天冬酰胺、组氨酸、蛋氨酸和丝氨酸（p≤0.001）、丙氨酸、亮氨酸、赖氨酸和脯氨酸（p≤0.05）的浓度显著降低。酮病奶牛中总生酮和生糖氨基酸显著增加（p≤0.05），且总生酮和生糖氨基酸与总氨基酸的比例增加（p≤0.001）。在我们的研究中，特别是在原发性酮病奶牛中观察到的氨基酸浓度变化，表明其在酮体生成和糖异生过程中被大量利用。因此，详细了解氨基酸在糖异生和酮体生成中的作用将改善酮病的诊断和监测酮病发作过程。也许，通过在氨基酸含量方面平衡适当的饲料配方可以预防这种疾病。
