Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China; Departamento de Producción Animal y Pasturas, Facultad de Agronomía, Universidad de la República, Avda Garzón 780, Montevideo, CP 12900, Uruguay.
Department of Infectious Diseases and Public Health, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Hong Kong, China.
Animal. 2024 Feb;18(2):101049. doi: 10.1016/j.animal.2023.101049. Epub 2023 Dec 8.
Our understanding of metabolic alterations triggered by heat stress is incomplete, which limits the designing of nutritional strategies to mitigate negative productive and health effects. Thus, this study aimed to explore the metabolic responses of heat-stressed dairy cows to dietary supplementation with vitamin D/Ca and vitamin E/Se. Twelve multiparous Holstein cows were enrolled in a split-plot Latin square design with two distinct vitamin E/Se supplementation levels, either at a low (ESe-, n = 6, 11.1 IU/kg vitamin E and 0.55 mg/kg Se) or a high dose (ESe+, n = 6 223 IU/kg vitamin E and 1.8 mg/kg Se) as the main plot. Treatment subplots, arranged in a replicated 3 × 3 Latin square design, comprised heat challenge (Temperature Humidity Index, THI: 72.0-82.0) supplemented with different levels of vitamin D/Ca: either low (HS/DCa-, 1 012 IU/kg and 0.73%, respectively) or high (HS/DCa+, 3 764 IU/kg and 0.97%, respectively), and a pair-fed control group in thermoneutrality (THI = 61.0-64.0) receiving the low dose of vitamin D/Ca (TN). The liquid chromatography-mass spectrometry-based metabolome profile was determined in blood plasma and milk sampled at the beginning (day 0) and end (day 14) of each experimental period. The results were analyzed for the effect of (1) TN vs. HS/ESe-/DCa-, and (2) the vitamin E/Se and vitamin D/Ca supplementation. No group or group × day effects were detected in the plasma metabolome (false discovery rate, FDR > 0.05), except for triglyceride 52:2 being higher (FDR = 0.03) on day 0 than 14. Taurine, creatinine and butyryl-carnitine showed group × day interactions in the milk metabolome (FDR ≤ 0.05) as creatinine (+22%) and butyryl-carnitine (+190%) were increased (P < 0.01) on day 14, and taurine was decreased (-65%, P < 0.01) on day 14 in the heat stress (HS) cows, compared with day 0. Most compounds were unaffected by vitamin E/Se or vitamin D/Ca supplementation level or their interaction (FDR > 0.05) in plasma and milk, except for milk alanine which was lower (-69%, FDR = 0.03) in the E/Se+ groups, compared with E/Se-. Our results indicated that HS triggered more prominent changes in the milk than in the plasma metabolome, with consistent results in milk suggesting increased muscle catabolism, as reflected by increased creatinine, alanine and citrulline levels. Supplementing with high levels of vitamin E/Se or vitamin D/Ca or their combination did not appear to affect the metabolic remodeling triggered by HS.
我们对热应激引起的代谢变化的理解还不完全，这限制了设计营养策略来减轻负面生产和健康影响的能力。因此，本研究旨在探讨日粮补充维生素 D/Ca 和维生素 E/Se 对热应激奶牛的代谢反应。12 头经产荷斯坦奶牛采用二因子拉丁方设计，分为两个维生素 E/Se 补充水平的主区，即低剂量（ESe-，n = 6，11.1 IU/kg 维生素 E 和 0.55 mg/kg Se）或高剂量（ESe+，n = 6，223 IU/kg 维生素 E 和 1.8 mg/kg Se）。处理副区，按复制 3×3 拉丁方设计排列，包括热应激（温湿度指数，THI：72.0-82.0）补充不同水平的维生素 D/Ca：低剂量（HS/DCa-，1012 IU/kg 和 0.73%）或高剂量（HS/DCa+，3764 IU/kg 和 0.97%），以及在热中性条件（THI = 61.0-64.0）下接受低剂量维生素 D/Ca（TN）的配对喂养对照组。在每个实验期的开始（第 0 天）和结束（第 14 天）时，通过基于液相色谱-质谱的代谢组学方法测定血浆和牛奶中的代谢谱。分析了（1）TN 与 HS/ESe-/DCa-，以及（2）维生素 E/Se 和维生素 D/Ca 补充的影响。血浆代谢组中未检测到组或组×天的影响（错误发现率，FDR>0.05），除了第 0 天的甘油三酯 52:2 高于第 14 天（FDR=0.03）。牛磺酸、肌酸和丁酰肉碱在乳代谢组中表现出组×天的相互作用（FDR≤0.05），因为第 14 天的肌酸（+22%）和丁酰肉碱（+190%）增加（P<0.01），而第 14 天的牛磺酸减少（-65%，P<0.01）在热应激（HS）奶牛中，与第 0 天相比。大多数化合物在血浆和牛奶中不受维生素 E/Se 或维生素 D/Ca 补充水平或其相互作用的影响（FDR>0.05），除了牛奶中的丙氨酸，其水平较低（-69%，FDR=0.03）在 E/Se+组中，与 E/Se-相比。我们的结果表明，HS 对乳代谢组的影响比血浆代谢组更为显著，乳中一致的结果表明肌肉分解代谢增加，反映在肌酸、丙氨酸和瓜氨酸水平增加。补充高剂量的维生素 E/Se 或维生素 D/Ca 或它们的组合似乎并没有影响 HS 引起的代谢重塑。
