Abstract: 【Objective】The aim of the present study was to try to cryopreserve porcine oocytes efficiently, and to investigate the effect of cryopreservation method, cryopreservation tool and types of cryoprotectant on pig oocyte suvival and its in vitro maturation and cleavage following IVF and IVC. 【Method】Experiments in pig oocyte cryopreservation and in vitro fertilization（IVF） were conducted using oocytes collected from a slaughterhouse. The effects of different methods and different cryoprotectant solution on cryopreservation of porcine oocytes were examined. Survival was assessed by trypan blue (TB) staining, fluorescein diacetate (FDA) staining, maturation in vitro and cleavage after IVF. The results were showed as follows: 【Results】(1) Cryoprotectant solution (9%EG, 10%DMSO, 10%Gly) were effective to cryopreserve pig MII oocytes when in programmed freezing. The survival rates（FDA dyeing）of pig oocytes after frozen-thawed were very significantly higher than that of control (33.8%, 25.8%, 23.5% vs 2.5%, P <0.01). Among these three cryoprotectant solution, 9%EG was significantly superior to the other two in survival rate (33.8% vs 25.8%, 23.5%, P<0.05). (2)The freezing method by GMP (glass micropipette) was suitable and efficient to cryopreserve pig oocytes. Compared with programmed freezing method using Straw，GMP method could significantly promote the survival rate of pig oocytes (63.3% and 34.5%, respectively，P <0.05). (3) The vitrification solution carrier had a positive effect on survival rate of pig oocytes. When EFS40 was used as vitrification solution，Straw and GMP led to different survival rates, which were 45.0% and 65.9%, respectively (P <0.05). (4) The programmed freezing method by Straw and vitrification method by GMP were available in cryopreservation of pig oocytes, but these two methods resulted in different survival rates (30.0% and 59.7%, respectively, P <0.05). (5) Cryopreservation had a great effect on the developmental ability of pig oocytes after IVF and IVC. Vitrified MII oocytes were fertilized with fresh spermatozoa and only 4.9% eggs cleaved after 48 culture, which was very significantly lower than the cleavage rate of control(49.5%, P <0.01). The subsequent developmental rate to 4-cell stage was 1.7%, but none to 8-cell stage. 【Conclusion】The cryopreservervation of porcine oocytes with MII oocytes, vitrification and GMP were efficient.

Key words: Pig, Oocyte, Cryopreservation, In vitro fertilization (IVF)