Successful establishment of chicken primordial germ cell (PGC) lines from the endangered Slovakian indigenous chicken breed: the Oravka

PGCs offer a viable means for cryobanking both female and male avian genetic material. These early-migrating cells ultimately give rise to eggs and sperm cells, making them valuable for long-term conservation of poultry genetic resources. In this study, PGCs from the endangered Oravka chicken, a local breed native to Slovakia, were isolated, propagated in vitro, characterized, and cryopreserved. A total of 18 stable PGC lines were successfully established, comprising 12 female and 6 male lines. Characterization using immunohistochemistry, gene expression analysis, karyotyping, cell proliferation assays, TEM, and in vivo migration assays confirmed the identity and developmental competency of the in vitro cultured PGCs. A total of 108 cryopreserved samples were deposited into the gene bank. This study reports the first successful derivation, in vitro culture and cryobanking of stable PGC lines from the Oravka breed, providing a foundational resource for the conservation and future restoration of this distinctive local genetic lineage.