Discovery in Egg Yolk Unlocks Stem Cell Breakthrough Across Bird Species
Researchers at Kumamoto University, in collaboration with international partners from the United States, have uncovered a key ingredient in egg yolk that enables the long-term cultivation of embryonic stem cells from chickens and seven other bird species. This breakthrough, published in Nature Biotechnology, opens new doors for avian research, biodiversity conservation, and even future applications such as cultivated meat production.Embryonic stem cells (ES cells) are unique because they can both self-renew and transform into any cell type in the body, including germ cells. While ES cells have been successfully derived from mammals such as mice and rats, scientists had struggled for decades to establish authentic ES cells in birds.
The Kumamoto University team discovered that ovotransferrin, a protein naturally found in egg yolk, plays a crucial role in supporting stem cell growth. When combined with specific small-molecule inhibitors that block signals driving unwanted differentiation, ovotransferrin allowed chicken ES cells to remain stable and pluripotent over long periods. The researchers then optimized the culture conditions for other bird species—including quail, duck, turkey, goose, pheasant, peafowl, and ostrich—revealing species-specific requirements but ultimately achieving success across all eight.
“These avian stem cells show the ability to differentiate into all three germ layers and germ cells, confirming their authenticity,” said Dr. Guojun Sheng, Professor at Kumamoto University’s International Research Center for Medical Sciences (IRCMS). “This is the first time we can reliably establish germline-competent ES cells in birds, which has enormous implications for science and society.”
Beyond advancing developmental biology and poultry research, the findings could transform conservation efforts. Authentic avian ES cells provide a scalable platform for genetic engineering and preservation of endangered or even extinct bird species. They also offer new opportunities for biotechnology, such as producing genome-edited poultry models or sustainable cultivated meat.
Colony of chicken embryonic stem cells
| Authors | Xi Chen*, Zheng Guo, Xinyi Tong, Xizi Wang, Xugeng Liu, Hiroki Nagai, Ping Wu, Jiayi Lu, David Huss, Martin Tran, Carol Readhead, Christina Wu, Lin Cao, Yixin Huang, Zhaohan Zeng, Fan Feng, Nima Adhami, Sirjan Mor, Rusty Lansford, Cheng-Ming Chuong, Guojun Sheng, Carlos Lois, Qi-Long Ying* . (* co-first author） |
| Title of original paper | Derivation of embryonic stem cells across avian species |
| Journal | Nature Biotechnology |
| DOI | 10.1038/s41587-025-02833-3 |