营养不足引起泌乳母猪断奶后发情推迟或失败，原因在于体内代谢激素Leptin和IGFI分泌减少，导致情期启动关键蛋白Kisspeptin表达量降低，不能激活GnRH神经元，从而抑制情期启动，但营养调控代谢激素合成与分泌的机制仍不清楚。鼠上研究发现，肝脏雌激素受体（ERα）在介导营养调控代谢激素合成和繁殖功能转换中发挥重要作用，然而，在猪上未见报道。本项目采用母猪肝细胞培养和转染ERα细胞模型，研究氨基酸对肝脏ERα的激活和IGFI的合成效应及其作用信号通路；进一步选用高失重断奶母猪，采用恒流灌注氨基酸，证实补充氨基酸可通过肝脏ERα活性介导IGFI合成，并促进Kisspeptin分泌，启动发情，同时验证繁殖组织发育的同步性；采用动物试验筛选高失重母猪由断奶向发情快速转换的氨基酸日粮。本研究对揭示营养与繁殖功能转换的分子机理具有重大理论意义，并对提高断奶母猪的发情率和繁殖成绩具有重大实践意义

Nutrition deficit caused delayed return to estrus cyclicity and even reproductive failure in postweaning sows as a consequence of inadequate secretion of metabolic hormone Leptin and IGFI to induce sufficient central kisspeptin expression, a protein required for normal pulsatile GnRH release, however, the mechanism responsible for the nutritional regulation of metabolic hormones secretion remains unclear. Researh in mice revealed that liver estrogen receptor alpha (ERα) played a critical role in directing nutrition-dependent secretions of metabolic hormones and integrating metabolic and reproductive functions, yet the phsiological role of hepatic ERα remained uncertain in sows. In present study, the signal pathway by which the amino acid-dependent activation of ERα responsible for IGFI secretion, if any, will be revealed using in vitro primary hepatic cell culture from lactating sows or ERα transfected hepatic cells. Using postweaning sows with severe body reserve mobilization, exogenous chronic amino acids were intravenously infused to confirm the IGFI secretion by amino acid-dependent activation of ERα, and further test whether this increased the central secretion of of kisspeptin to facilitate estrus cyclicity, and further confirms the developmental synchronization of reproductive tissue, e.g. uterus and ovaries. Based on the in vitro and in vivo tests, weaned sows with severe body reserve mobilization would be returing to estrus cyclicity advancely with optimized amino acid forticated diets. The results of the present study would shed light on the mechanisms integreting nutritional regimen and reproductive functions, and will also provide practical nutritional strategies to improve the percentage of estrus gilts and reproductive performance of postweaning sows.