Poultry genetic improvement towards climate adaptation and sustainable farming requires maintainance of the existing genetic diversity within and between breeds. Gene banks can assist in conserving this diversity and reintroducing important traits into current poultry lines. CRYOCHICK focuses on the development of effective cryopreservation methods for ex-situ of male and female chicken germplasm.
Current strategies for chicken germplasm cryopreservation
Current strategies for gene banking of chicken reproductive material are not adequate because 1) chicken sperm are very sensitive to cryopreservation, especially native breeds; 2) glycerol, the most effective sperm cryoprotectant, is contraceptive in the hen; 3) cryopreservation of semen alone does not capture genes of mitochondria and the W sex-chromosome; on the other hand, cryopreservation of chicken oocytes and embryos is currently impossible; 4) cryopreservation of female primordial germ cells (PGCs) is possible, but laborious, and costly. Therefore, new strategies for cost-effective gene banking, and new effective cryopreservation methods for both male and female chicken germplasms are required.
New approaches needed
Effective chicken gene banking requires improving post-thaw survival and functionality of sperm cells and female germplasm. CRYOCHICK looks for reducing loss of functional intactness of sperm cells and female gonadal germ cells related to ice formation, and searches for adequate cryopreservation protocols that render sufficient post-thaw fertility. CRYOCHICK proposes to 1) minimize supercooling (shown to be detrimental in boar semen) − by inducing early ice nucleation either mechanically or through the use of nucleating proteins − and 2) to minimize ice recrystallization through the use of anti-freeze proteins.
The goal of CRYOCHICK is to contribute in the development of a more adequate cryopreservation protocol for male and female germplasm and to analyze and design alternative approaches to optimize the strategy for functional poultry gene banking.