Abstract: Objective EFS40、EFS20、mEFS40、mEFS20 solution was used to cryopreserved rabbits，morula economically and effectively. Methods Three protocols were selected in this experiment. Using mEFS40 medium ( modified EFS40) (40% Ethylene glycol+ 180ppm Ficoll70(W/v)+ 0.3mol/L Sucrose in PB1) as a cryoprotective solution，rabbit morula were equilibrated two minutes in mEFS20 medium, then equilibrated in mEFS40 cryoprotective solution one minutes. After that they were transferred into plastic insemination straws. The straws were kept on the liquid nitrogen for two minutes. Finally the straws with embiyos was put into the liquid nitrogen. The solutions used in project two were replaced with EFS20 and EFS40, the other procedure was the same as the project one. Only EFS40 solution was used in project three, the embryos were washed three times with EFS40 and transferred into the plastic insemination straws, then put the straws into the liquid nitrogen directly. All cryopreserved embryos were thawed in 25 °C water, and incubate in PB1 solution. Results The post-thaw survival in three protocols was 17.1%, 69.6% and 36.1% respectively. Conclusions The rabbits morula can be effectively cryopreserved by using the EFS40 as the cryoprotectant and EFS20 as the equilibrated solution (progeet two).

Key words: Cryoprotective solution, Cryop reservation, Rabbit, Embryo