Abstract
The purpose of the present experiment was to determine the fertilizability of bovine oocytes frozen in various cryoprotectants: 1.6 M 1,2-propanediol (PROH)+0.2 M sucrose, 1.6 M dimethylsulfoxide (DMSO)+0.2 M sucrose, 1.6 M glycerol (GL)+0.2 M sucrose, 0.8 M PROH+0.8 M DMSO, and 0.8 M PROH+0.8 M GL. The incidence of morphologically normal oocytes was significantly higher in the 0.8 M PROH+0.8 M DMSO group (56.0%) than in other groups (P<0.05). At 48 h after insemination, the number of eggs that cleaved into the 2-cell stage, in both the 0.8 M PROH+0.8 M DMSO and 1.6 M PROH+0.2 M sucrose groups, was significantly greater than in other groups (P<0.05). By analyzing the chromosomes of first-cleavage eggs, which were fertilized in vitro after freezing and thawing, it was found that the incidences of polyploids were higher in all of the frozen-thawed groups than in the control group, but among them there was no significant difference. The frequency of eggs with chromosomes having structural aberrations did not increase in any of the treated groups.
