Ultra-rapid freezing and storage of rat embryos in an electric refrigerator at -130 degree C without liquid cryo-agents, with ultra-short exposure in the freezing medium and direct rehydration after thawing.

An ultra-rapid freezing technique for embryos has been developed. This procedure involves: ultra-short exposure to cryoprotectants; freezing of embryos in a metallic powder pre-cooled in an electric refrigerator at -130 degree C; storage of embryos ina refrigerator at -130 degree C; direct rehydration after thawing.