Efficient system for preservation and regeneration of genetic resources in chicken: concurrent storage of primordial germ cells and live animals from early embryos of a rare indigenous fowl (Gifujidori).

The unique accessibility of chicken primordial germ cells (PGCs) during early development provides the opportunity to combine the reproduction of live animals with genetic conservation. Male and female Gifujidori fowl (GJ) PGCs were collected from the blood of early embryos, and cryopreserved in liquid nitrogen for >6 months until transfer. Manipulated GJ embryos were cultured until hatching; fertility tests indicated that they had normal reproductive abilities. Embryos from two lines of White Leghorn (24HS, ST) were used as recipients for chimera production following blood removal. The concentration of PGCs in the early embryonic blood of 24HS was significantly higher than in ST (P < 0.05). Frozen-thawed GJ PGCs were microinjected into the bloodstream of same-sex recipients. Offspring originating from GJ PGCs in ST recipients were obtained with a higher efficiency than those originating from GJ PGCs in 24HS recipients (23.3% v. 3.1%). Additionally, GJ progeny were successfully regenerated by crossing germline chimeras of the ST group. In conclusion, the cryogenic preservation of PGCs from early chicken embryos was combined with the conservation of live animals.