Abstract Serotonin (5-HT) is essential for neuronal development and behavioral regulation. Serotonin, upon in ovo administration, has been previously reported to modulate aggressive behavior in avian species, however it still remains unknown if maternal serotonin affects chick behavior through hypothalamic gene expression. We injected an equal volume of saline (control) and either a 5 μg (low) or a 15 μg (high) dose of 5-HT into embryos on embryonic day 11 (E11). The blood concentration of 5-HT was determined in chicks on post-hatching D3 (Day 3) and D45. The behavioral fear and aggression were analyzed at D10 and D52. In isolation test, the latency to vocalize and walk, the duration of vocalizations and walking were recorded. Hypothalamic expression of genes related to the serotonin pathway and the methylation status of hypothalamic 5-HT 1A receptor (5-HTR1A) were measured at D56. Chicks treated with embryonic 5-HT exhibited a certain decrease in the degree of fear as determined by the duration of vocalizations (p

中文翻译：

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卵内注射血清素对孵化后雏鸡行为和下丘脑基因表达的影响

摘要 血清素 (5-HT) 对神经元发育和行为调节至关重要。之前有报道称血清素在卵内给药后可调节鸟类的攻击行为，但母体血清素是否通过下丘脑基因表达影响小鸡行为仍然未知。我们在胚胎第 11 天 (E11) 将等量的盐水（对照）和 5 μg（低）或 15 μg（高）剂量的 5-HT 注射到胚胎中。在孵化后第 3 天（第 3 天）和第 45 天测定小鸡的 5-HT 血液浓度。在第 10 天和第 52 天分析行为恐惧和攻击性。在隔离测试中，记录发声和行走的潜伏期、发声和行走的持续时间。在第 56 天测量与血清素途径相关的基因的下丘脑表达和下丘脑 5-HT 1A 受体 (5-HTR1A) 的甲基化状态。用胚胎 5-HT 处理的小鸡表现出的恐惧程度有一定的降低，这取决于发声的持续时间（p