关键词: 鸡；性别反转；雌激素；DMSO

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