Some factors for porcine embryos vitrification

The purpose of this study was to optimize the procedure for cryopreservation of porcine embryos by vitrification.5-6 day-embryos(blastocyst/morula)were collected from superovulated Bama mini-pigs(sows/gilts).Different cryopreservation methods,cryopreservation tools,thining of zona pellucida(ZP) and recipient breeds were compared.The results were as follows:there were no significant different between two freezing method in embryo survival rate and cell number;the GMP vitrification method was more suitable and efficient in cryopreservation of pig embryos,the embryo survival rate(83.8% vs 77.6%) and blastocyst cell number(53.1 vs 47.5) were significantly higher than the OPS method(P0.05);there were no significant differences in vitro survival rate by thinning the ZP(0.5% pronase,10 s) after warming but significantly improved the blastocyst cell number in surviving blastcysts(60.1% and 46.6%,P0.01);the local pig breeds(Fengjing sows) are more suitable as recipients for vitrified/warmed blastcysts in the pregnancy rate and embryos efficiency(P0.01).