Developmental capacity of bovine oocytes frozen in different cryoprotectants

Iso-osmolar concentrations of 1.6 M of 1,2-propanediol, glycerol and dimethylsulfoxide were compared for their effectiveness as cryoprotectants for in vitro-matured bovine oocytes. Survival, defined as the number of morphologically normal oocytes, after freeze-thawing in 1,2-propanediol (49.8%) was significantly higher (P<0.01) than in glycerol (28.6%) or dimethylsulfoxide (32.6%). After insemination, the fertilization rate of morphologically normal oocytes frozen-thawed in 1,2-propanediol (57.9%) was higher (P<0.05) than that of those frozen in dimethylsulfoxide (38.3%). However, the proportion of surviving oocytes developing to blastocysts was not different among the 3 groups.