Study On The Oocytes IVM And Cryopreservation In Sheep

Oocytes cryopreservation is a potentially valuable technique for conservation of animal genetic resources. The best condition and viable technique route of ovine oocytes cryopreservation could be established through this study. In this experiment, the effect of collection methods, hormone ratio, estrous cycle, cumulus cells, glutamine and EGF were discussed; the influence of freezing and thawing methods on developmental capability of ovine GV and MII stage oocytes were examined in this paper. Oocytes were frozen at GV and MII stage, using programmed freezing, straw vitrification and open pulled straw vitrification (OPS), fresh oocytes served as controls, and the results were as follows:1 There were significantly differences among isolating methods. the number of useable oocytes per ovary through integration and slicing was 1.71 and 1.58, which was higher than aspiration(0.92,P<0.05); there was no difference among the three methods in maturation rate(58.9%,62.3%,62.0%;P>0.05), but in cleavage rate aspiration was lower than the others (28.6%,49.5%,45.8%;P<0.05).2 The maturation rate of different hormone ratio were 55.6%,67.2%,66.7%,73.8%, D-group was significantly higher than A-group(P<0.01), there was on significantly difference in cleavage (32.9%,42.4%,40.7%,45.2%, P>0.05), but the value was mounted up. The best group was 10μg/mlFSH+10μg/ml LH.3 The maturation rate of A and B grade was significantly higher than C grade(75.3%,64.4%,29.1%,P<0.01) and the same to cleavage rate (42.5%,35.8%,16.0%,P<0.05). 4 Oocytes from different estrous cycle had the same developmental capability of maturation rate(67.1%,63.0%; P>0.05) and cleavage rate(42.9%,41.3%; P>0.05).5 Adding Glutamine did not have effect on in vitro maturation an in vitro fertilization (P>0.05).6 Adding 100ng/ml EGF could significantly improve the maturation rate (72.4%,56.8%,P<0.05) and cleavage rate (46.0%,25.9%,P<0.05).7 The maturation rate of ovine oocytes using programmed freezing method with EG,DMSO and GL was 21.9%,18.3%,8.97%, the result was EG>DMSO>GL; the maturation rate of ovine oocytes using OPS with different hormone ratio was 39.1%,26.0%,24.7%,(EG+DMSO)group>(EG+GL) group >(GL+DMSO) group,no difference between (EG+DMSO) group and (GL+DMSO) group.8 In GV-stage oocytes, the rate of morphologically normal oocytes(54.8%) and the maturation rate(14.7%) with programmed freezing method lower than straw(71.8%,29.5%;P<0.05) and OPS vitrification(78.3%,35.4%;P<0.05), there was no difference between OPS and straw vitrification in cleavage rate(26.1%,16.7%;P>0.05); In MII-stage oocytes, the same result was concluded in the rate...