Department of Animal Science, Cornell University, 48 Judd Falls Rd., Ithaca, 14853, NY, USA.
Animal. 2020 Mar;14(S1):s165-s175. doi: 10.1017/S1751731119003185.
Coordinated changes in energy metabolism develop to support gestation and lactation in the periparturient dairy cow. Maternal physiology involves the partitioning of nutrients (i.e. glucose, amino acids and fatty acids (FA)) for fetal growth and milk synthesis. However, the inability of the dairy cow to successfully adapt to a productive lactation may trigger metabolic stress characterized by uncontrolled adipose tissue lipolysis and reduced insulin sensitivity. A consequence is lipotoxicity and hepatic triglyceride deposition that favors the development of fatty liver disease (FLD) and ketosis. This review describes contemporary perspectives pertaining to FA surfeit and complex lipid metabolism in the transition dairy cow. The role of saturated and unsaturated FA as bioactive signaling molecules capable of modulating insulin secretion and sensitivity is explored. Moreover, the metabolic fate of FA as influenced by mitochondrial function is considered. This includes the influence of inadequate mitochondrial oxidation on acylcarnitine status and the use of FA for lipid mediator synthesis. Lipid mediators, including the sphingolipid ceramide and diacylglycerol, are evaluated considering their established ability to inhibit insulin signaling and glucose transport in non-ruminant diabetics. The mechanisms of FLD in the transition cow are revisited with attention centered on glycerophospholipid phosphatidylcholine and triglyceride secretion. The relationship between oxidative stress and oxylipids within the context of insulin antagonism, hepatic steatosis and inflammation is also reviewed. Lastly, peripartal hormonal involvement or lack thereof of adipokines (i.e. leptin, adiponectin) and hepatokines (i.e. fibroblast growth factor-21) is described. Similarities and differences in ruminant and non-ruminant physiology are routinely showcased. Unraveling the lipidome of the dairy cow has generated breakthroughs in our understanding of periparturient lipid biology. Therapeutic approaches that target FA and complex lipid metabolism holds promise to enhance cow health, well-being and productive lifespan.
围产期奶牛的能量代谢协调变化以支持妊娠和泌乳。母体生理学涉及营养物质（即葡萄糖、氨基酸和脂肪酸（FA））的分配，以促进胎儿生长和牛奶合成。然而，奶牛无法成功适应生产性泌乳可能会引发代谢应激，其特征是不受控制的脂肪组织脂解和胰岛素敏感性降低。结果是脂毒性和肝甘油三酯沉积，有利于脂肪肝疾病（FLD）和酮病的发展。本综述描述了围产期奶牛 FA 过剩和复杂脂质代谢的当代观点。探讨了饱和和不饱和 FA 作为生物活性信号分子调节胰岛素分泌和敏感性的作用。此外，还考虑了 FA 对线粒体功能的代谢命运的影响。这包括线粒体氧化不足对酰基辅酶 A 状态的影响以及 FA 用于脂质介质合成的情况。考虑到脂质介质，包括鞘脂神经酰胺和二酰基甘油，在非反刍动物糖尿病中抑制胰岛素信号和葡萄糖转运的既定能力，对其进行了评估。围产期奶牛 FLD 的机制被重新审视，重点关注甘油磷脂卵磷脂和甘油三酯的分泌。还回顾了氧化应激与 oxylipids 之间的关系，包括胰岛素拮抗、肝脂肪变性和炎症。最后，还描述了围产期激素对脂肪因子（即瘦素、脂联素）和肝因子（即成纤维细胞生长因子-21）的参与或缺乏情况。反刍动物和非反刍动物生理学的相似性和差异性通常会得到展示。奶牛脂质组学的研究取得了围产期脂质生物学理解的突破。针对 FA 和复杂脂质代谢的治疗方法有望提高奶牛的健康、福利和生产寿命。
