A successful technique for the preservation of rabbit embryos

A technique for successfully freezing, thawing and transferring rabbit embryos has been developed. Morula stage embryos were collected from super-ovulated female rabbits by flushing both oviducts and uterine horns with a tissue culture medium. Well developed, viable embryos were then transferred to freezing vials and a cryoprotectant, dimethyl sulfoxide (DMSO) was added in several steps to bring its final concentration to 1.6 molar. To freeze the embryos the temperature was lowered slowly (either 0.5 degrees C/min or 1.0 degrees C/min) to -80 degrees C at which point the vials were transferred directly to liquid nitrogen (-196 degrees C). Thawing was done at 8 degrees C/min. After thawing, phosphate buffered saline was added in a stepwise manner to dilute the DMSO. The thawed embryos were then cultured at 37 degrees C. Transfer of the embryos was accomplished by laparotomizing a pseudopregnant doe and introducing the embryos into the fimbriated ends of the oviducts. The 101 positively transferred embryos resulted in 45 implantations and 34 live born young.