Cryopreservation Of Porcine Oocytes And Embryos By Vitrification

Several studys have demonstrated that the sensitivity of porcine oocytes and embryos to lowered temperatures may relate to their relatively high lipid content. The absence of effective oocyte and embryo cryopreservation technologies may not only result in a major loss of genetic diversity in this species, but also hinder application of reproductive technologies.In the present study, survival of vitrificated oocytes was assessed by fluoresecin diactate staining and fertilization. The embryos were surgically collected and cryopreservated by vitrification after warmed and embryo transfer. The results were shown as follows:1) Toxicity of six cryoprotectants including three osmotic ones EG, GL and DMSO and nonosmotic ones sucrose, ficoll and FCS, for porcine oocytes was investigated. The toxicity of three osmotic cryoprotecent from the high the low was found EG > GL > DMSO, and there was no significant difference in toxicity between sucrose, ficoll and FCS (p>0.05).2) One-step method was adopted to compare the effects of cryoprotectants EFS30, EFS40, GFS40, EDFS40 on oocytes. The cryoprotectant EFS40 gave the best result3) The experiments of equilibrium duration of vitrificated oocytes in EFS for different times showed the equilibrium duration of 30 seconds was optimum.4) Comparison was made of effect of carriers ,GMP, OPS and GLT, on survival of porcine oocytes cryopreservation, with the survival rate being 13.4%, 29.5% and 55.8% respectively and GLT method for oocyte vitrification being the best (p<0.01).5) The survival rate of different developmental stages at GV, 22h, MII was 22.0%, 39.6% and 53.6%respectively.6) Under the condition of addition of 5ug/mL CB in each group, the effects of centrifugation, lipid removal treatmenton in vitro maturation in porcine oocytes were investigated, and no significant differences were observed between the groups.7) The vitrificated/warmed oocytes were fertilizerated with IVF, the cleavage embryoes by ICSI were observed and developed to 4-cell stage. However, no cleavage embryo...