Comparison of pregnancy rates for days 7-8 equine embryos frozen in glycerol with or without previous enzymatic treatment of their capsule

摘要

The inability of large equine embryos to survive standard cryopreservation protocols is well documented. The embryonic capsule seems to impede the successful freezing of equine embryos [1-5]. In a previous and preliminary study [5], it was suggested using enzymatic treatment on the capsule to increase its permeability before glycerol addition. In this last study, few pregnancies were observed after transfer of days 7-8 frozen/thawed embryos previously treated by trypsin. The aim of the present study was to compare the pregnancy rates after transfer of embryos frozen by this process (Patent FR 97073011/PCT) and embryos frozen with a standard protocol.