反刍动物泌乳期的营养分配及其调控机制

泌乳期是哺乳动物的一个重要生理时期。随泌乳期开始,动物整体的营养分配和新陈代谢发生显著变化,以满足乳腺的需要。其净影响是乳腺新陈代谢速度和养分利用增加,非乳腺组织养分利用减少。泌乳期动物通过提高采食量或调用体贮来保证养分供给。随着泌乳期开始,肝脏糖异生速度显著提高,肝糖原被动员,葡萄糖氧化减少;脂质代谢速度增快,而脂肪组织中脂质合成速度下降。泌乳期营养分配的主要调节因子是激素。本文最后讨论了泌乳期各生理过程的协调作用,并举例说明了其重要性。

Nutrient Partitioning and Its Regulation Mechanism during Ruminants Lactation

At the initiation of lactation, marked alterations in the partitioning of nutrients and metabolism of the whole animal must occur to accommodate demands of the mammary gland. The net effect is the increase in mammary gland metabolic rate and nutrient use and decrease in the nutrient use of non-mammary tissues. During lactation, feed intake is increased and body reserves is utilized to meet nutrient requirement. With the onset of lactation, the rates of gluconeogenesis in the liver are increased dramatically, glycogen is mobilized, but the oxidation of glucose is decreased. The rates of lipid mobilization are increased and the rates of lipid synthesis in adipose tissue are decreased. The primary mediator is hormones in the partitioning of nutrients during lactation. Finally, the coordination of biological processes of lactation and importance of this coordination are discussed.