Studies On The IVM And Cryopreservation Of Bovine Follicular Oocyte

This study applied different culture mediums and cryopreservation methods to culture and preserve bovine follicular oocytes in order to select the better culture medium and cryopreservation method. The good-quality morphologically cumulus oocyte complexes(COCs) were collected by aspiration from the 2-8 mm follicular in the ovaries collected from the slaughter house. The COCs were used for culture and cryopreservation. The results were as follow:1.The corresponding maturation rate, development rate of oocytes had nosignificant differences(f>0. 05) between in 4-well plates containing400 u L of culture medium overlaid mineral oil and in traditionaldroplets containing 100 u L medium.2. The maturation rate , cleavage rate and development rate of COCscultured in medium added 10% estrum calf serum(ECS, V/V) and 10% bovine follicular fluid(BFF, V/V) were similar to that of COCs cultured in medium added hormone(64% vs 63%, 38. 3% vs 38. 6%, 21.3% vs 23.1% ).The result indicated that addition of 10%ECS and 10%BFF was practicable.3.The culture results were no significant differences (P>0. 05) between the heat-treat serum and the primitive serum added to culture medium , the mature rate were 58. 5% and 61. 5%, respectively. But it was difficult to operate COCs if the serum was not heat-treated, so the heat-treat serum was used.4. The rusults were significant differences(P<0.05) between the filtered BFF and the primitive BFF, the mature rate were 38. 3% and 56. 5%,respectively. It was suggested to add primitive BFF to mature medium.5. It was suited to mature oocytes from 2-6 mm follicular for 22-24 h. The mature time was not suit to other bigger follicular(>6mm), the mature rates were 62. 6% and 49. 6%, respectively, the differences were significant (KO. 05).6. As the holding medium, TCM199 and PBS had significant differences in conventional freezing procedures, but the difference was not significant in ultrarapid freezing and vitrification. The mature rates were 9. 7% vs 18. 8%, 12. 9% vs 13. 3%, 17. 0% vs 16. 8% respectively using TCM199 and PBS as the holding medium in the three cryopreservation method.7. Acting as the cryoprotectant, ethylene glycol(EG) and glycerol had significant differences(KO.05) in conventional freezing procedures (the mature rate 15.9% vs 11.9%) and ultrarapid freezing (the mature rate 18.7% vs 11.7%).8. The method of cryopreservation and development stage had significant effects on the development capacity of frozen-thawed bovine oocytes.The rate of morphological normality, maturation, fertilization and cleavage were 76.3%, 71.1%, 84.7%; 13. 0%, 14.9%, 17. 4%;17. 2%, 17. 8%, 21. 3%; 9.7%, 13. 4%, 18. 0% in conventional freezing procedures, ultrarapid freezing, vitrification respectively. The vitrification was the best among the three cryopreservation method. The cleavage rates and fertilization rates were 10. 6%, 6.4% in GV oocytes, but that were 27. 2%, 19, 4% in the matured oocytes. The cleavage rates and fertilization rates of GV oocytes were significant lower than that of the IVM oocytes.