Studies On The Fertilizable Competences Of Cryopreservated Bovine Oocytes

Cumulus oocytes complexes(COCs) were recovered from Φ2～6 mm superficial follicles of slaughter discarded ovaries ,then cryopreservated by different vitrification methods immediately or after mature culture for 24 hours. After that, the comparison of the fertilizable competences of ICSI and IVF on cryopreservated oocytes was studied in this article, in order to establish an optimized method to improve the fertilizable competences of oocytes up to the level of embryos'.1 Effects of the reducing injury methods on IVF of cryopreservated oocytesThe result of the three methods, choosing the right time oocytes, using minimum size sample vitrification and culturing after thawing, showed that these ways could partly maintained the fertilizable competences of cryopreservated bovine oocytes. Considering the cleavage rate, mature cultured oocytes was significantly better than immatured oocytes(in GMP vitrification P<0.01(19.5%vs 11.6%), in straw vitrification P<0.05(17.6% vs 10.3%)). GMP vitrification was better than straw vitification not only mature cultured oocytes(19.5% vs 17.6%) but also immatured ones(11.6% vs 10.3%), but they both had no significant difference(P>0.05). Culturing 1 hour and 3 hours after thawing were significantly better than control group, but the difference between culturing lhour and 2 hours and 3 hours after thawing were not significant both about the fertilization rates and cleavage rates, but the cleavage rates decreased with the increasing culture time. They were all better than control group but had no significant difference (P>0.05).2 Factors affecting intracytoplasmic sperm injection (ICSI) which was penetrating zona pallucidaThe result of improving ICSI technology showed that sperm treated with DTT before fertilization has better cleavage rate than the other treat groups (P>0.05), and was significantly better than control group (P<0.05).But when using IVF technology to GMP cryopreservated oocytes, sperm treated with heparin before fertilization was significantly better on the cleavage rate than the caffein group(P<0.05) and control group(P<0.01), but have no significant difference with DTT group(P>0.05). The study of different sperm...