Abstract: Significant market disparities exist in the poultry industry based on sex，with female chickens prefereed for their superior egg?laying performance and desirable meat traits. This practice results in the wastage of approximately 50% of fertilized eggs，underscoring the need for early sex determination to improve breeding efficiency and resource utilization. Sex differentiation in chickens is a complex biological process. Notably，exogenous estrogen administration during the developmental window can induce phenotypic feminization in genetically male individuals. In this study，fertilized eggs of Huiyang Bearded Chicken eggs were injected with exogenous estrogen on day 3 of incubation to establish an efficient and stable sex reversal protocol. We first compared the effects of different estrogens （17α ? ethynylestradiol，β ? estradiol），solvents（emulsifier，95% ethanol，DMSO），and injection sites. Results indicated that yolk injection of 17α?ethynylestradiol dissolved in DMSO yielded higher sex reversal efficiency and lower mortality compared to other treatments. Further dose optimization revealed that injection of ≥80 μg per egg induced 100% sex reversal. In conclusion，the optimal protocol was established：yolk injection of 80 μg of 17α? ethynylestradiol（dissolved in DMSO）on incubation day 3 reliably induced 100% male?to?female sex reversal. These findings provide experimental evidence for understanding sex differentiation mechanisms and offer a theoretical foundation for developing sex control technologies in poultry breeding.

Key words: Chicken；Sex reversal；Estrogen；DMSO

摘要： 在家禽养殖业中存在由性别所致的市场需求差异，雌性个体因产蛋性能和肉质性 状较优而被选育，使得产业中约50%的种蛋资源被浪费。因此，早期性别鉴定对提高育种效 率、减少资源损耗具有重要意义。鸡的性别分化是个复杂的生物学过程，在性别分化关键窗口 期实施外源雌激素干预，可成功诱导遗传雄性个体表型雌性化。该研究以惠阳胡须鸡种蛋为 试验材料，在孵化第3天通过注射外源雌激素，旨在探究高效、稳定的性别反转诱导方案，并 筛选最优处理条件。首先，该研究比较了不同雌激素(17α?乙炔基雌二醇、β?雌二醇)、溶剂(乳 化剂、95%酒精、DMSO) 以及注射部位对性别反转效果的影响。结果表明，与其他处理组相比， 以DMSO为溶剂、17α?乙炔基雌二醇为溶质的雌激素溶液，注射到蛋黄中，表现出更高的性别 反转效率和更低的致死率。进一步对注射剂量开展的优化试验表明，向每枚种蛋注射80 μg及 以上剂量的雌激素，能够实现100%性别反转。综上，该研究确立了鸡性别反转的最佳处理方 案：在种蛋孵化第3天时，向蛋黄中注射80 μg溶解于DMSO的17α?乙炔基雌二醇溶液，可实现 100%的鸡遗传雄性向表型雌性的性别反转诱导。该结果为性别分化机制研究提供了试验依 据，并为性别控制技术的开发提供了理论基础。

关键词: 鸡；性别反转；雌激素；DMSO