Reproductive Hormone and Transcriptomic Responses of Pituitary Tissue in Anestrus Gilts Induced by Nutrient Restriction

The onset of estrus is a critical sign of female sexual maturity. The pituitary plays a vital role in this process by the secretion of reproductive hormones. To investigate the effects of nutrient restriction on reproductive function and the underlying mechanisms involved, deep RNA sequencing of pituitary gland tissue was carried out to determine the differentially expressed genes (DEGs) between gilts in normal estrus, and gilts in which anestrus was induced by nutrient restriction. Gilts which had gone through two estrus cycles were fed a normal (CON, 2.86kg/d, n = 10) or nutrient restricted (NR, 1kg/d, n = 10) diet. The NR gilts experienced another three estrus cycles, but did not express estrus symptoms at the anticipated 6th and 7th cycles. Body weight gain in NR gilts was significantly decreased by nutrient restriction. Gilts were considered as anestrus when blood progesterone concentrations lower than 1.0 ng/mL from three consecutive blood samples were recorded. Circulating concentrations of progesterone (发情启动是雌性性成熟的关键标志。垂体通过分泌生殖激素在该过程中发挥至关重要的作用。为探究营养限制对生殖功能的影响及其潜在作用机制，本研究对垂体组织开展深度RNA测序（deep RNA sequencing），以鉴定正常发情后备母猪与营养限制诱导乏情后备母猪之间的差异表达基因（differentially expressed genes, DEGs）。经历过2个发情周期的后备母猪，被饲喂正常日粮（CON组，2.86kg/d，n=10）或营养限制日粮（NR组，1kg/d，n=10）。NR组后备母猪又经历了3个发情周期，但在预期的第6、7个发情周期未表现出发情症状。营养限制显著降低了NR组后备母猪的体重增长。当连续三次采集的血液样本中孕酮浓度均低于1.0 ng/mL时，判定该后备母猪为乏情状态。循环中孕酮的浓度（