Research Progress in the Establishment of Sterile Hosts and Their Usage in Conservation of Poultry Genetic Resources

Many local chicken breeds are rapidly declining and even facing extinction due to a variety of factors such as indiscriminate crossbreeding, climate fluctuations, epidemic outbreak, and environmental changes. Developing effective preservation strategies is important to address this situation. The special reproductive characteristics and gamete morphology of chickens pose challenges for preserving genetic heritage through the cryopreservation of genetic materials. Currently, gonad and primordial germ-cell cryopreservation and transplantation are the most promising approaches, especially for the genetic information in the W chromosome of female birds. The study of establishing sterile recipients is crucial for increasing the efficiency of the colonization of transplanted donor tissues and cells. Several classical methods, including ovariectomy and testectomy, busulfan, and irradiation, have been employed to deplete endogenous germ cells in recipient males before transplantation. These methods rely on the toxicity of chemical reagents and physical stimulation to kill germ cells. Recent advances in gene-editing technology have introduced sterile hosts via the knocking out of genes relevant to germ cells’ development. This review explores state-of-the-art technologies for preparing infertile avian recipients (mainly chickens) and aims to provide guidance for the conservation of poultry genetic material and breed restoration.