Age at first estrus is the earliest phenotypic indicator of future reproductive success of gilts. Prebreeding anestrus is a major reason for reproductive failure leading to culling of replacement gilts. The two types of prebreeding anestrus are delay in attaining puberty (prepubertal anestrus, PPA) and silent ovulation (behavioral anestrus, BA). Neural tissues such as amygdala and hippocampus play a major role in regulating sexual behavior, social interactions, and receptivity to males. Differences in gene expression in the amygdala and hippocampus of gilts were analyzed in three comparisons: 1) PPA cases and cyclic controls at follicular phase of estrous cycle, 2) BA cases and cyclic controls at luteal phase of estrous cycle, and 3) gilts at different stages of the ovarian cycle (cyclic gilts at follicular phase and luteal phase of estrous cycle) to gain functional understanding of how these rarely studied tissues may differ between pubertal phenotypes and different stages of the estrous cycle of gilts. Differentially expressed genes (DEG) between PPA and BA cases and their respective cyclic controls were involved in neurological and behavioral disorders as well as nervous system functions that could directly or indirectly involved in development of behaviors related to estrus. The comparison between cyclic follicular and luteal phase control gilts identified the greatest number of DEG in the hippocampus and amygdala. These DEG were involved in adult neurogenesis and neural synapse (e.g., GABAergic, dopamine, cholinergic), suggesting that these tissues undergo structural changes and synaptic plasticity in gilts. This is the first report to demonstrate that the stage of estrous cycle is associated with dynamic changes in gene expression within porcine hippocampus and amygdala and indicates a role of gonadal steroids in regulating their biology.

中文翻译：

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周期性和非周期性后备母猪杏仁核和海马体中的基因表达

初发情年龄是后备母猪未来繁殖成功率的最早表型指标。配种前未发情是导致淘汰后备母猪的繁殖失败的主要原因。繁殖前发情期的两种类型是青春期延迟（青春期前发情期，PPA）和静默排卵（行为性发情期，BA）。杏仁核和海马体等神经组织在调节性行为、社交互动和对男性的接受度方面起着重要作用。在三个比较中分析了后备母猪杏仁核和海马中基因表达的差异：1) 发情周期卵泡期的 PPA 病例和周期性对照，2) 发情周期黄体期的 BA 病例和周期性对照，和 3) 处于卵巢周期不同阶段的后备母猪（处于卵泡期和发情周期黄体期的周期性后备母猪），以获得对这些很少研究的组织在青春期表型和后备母猪发情周期不同阶段之间可能有何不同的功能性理解。PPA 和 BA 病例之间的差异表达基因 (DEG) 及其各自的循环控制涉及神经和行为障碍以及神经系统功能，这些功能可能直接或间接参与发情相关行为的发展。周期性卵泡和黄体期对照母猪之间的比较确定了海马和杏仁核中最大数量的 DEG。这些 DEG 参与成人神经发生和神经突触（例如，GABAergic、多巴胺、胆碱能），这表明这些组织在后备母猪中经历了结构变化和突触可塑性。这是第一份证明动情周期阶段与猪海马体和杏仁核内基因表达的动态变化相关的报告，并表明性腺类固醇在调节其生物学方面的作用。