Long term-cultured and cryopreserved primordial germ cells from various chicken breeds retain high proliferative potential and gonadal colonisation competency.

When derived from chicken embryos, avian primordial germ cells (PGCs) have been reported to keep their germline-specific properties and proliferative potential even after long-term culture and genetic modifications. Few teams to date have reported such long-term expansion and engineering without differentiation of primary avian PGCs' cultures. We have developed original and robust methods that allow more than 1 year culture, expansion and cryobanking of primary cultures of PGCs without obvious effects on their biological properties, including their ability to colonise the genital ridges. Overall, 38% of embryonic samples gave rise to PGCs lines derived from three commercial layers and two Belgian endangered breeds. The lines kept their proliferative potential and their characteristic PGCs phenotype after 20 months in culture, whether or not interrupted by a cryopreservation step. All the resulting lines appeared devoid of female cells, although initially pooled from male and female embryos. Labelled PGCs from 12 long-term cultured lines colonised the genital ridges of recipient embryos. Thus, this procedure allows derivation, long-term expansion and cryobanking of primary cultures of PGCs without obvious changes to their original characteristics, providing an alternative access to applications in avian biotechnology and preservation of genetic resources.