Approaches in swine germplasm preservation: the effect of different cryoprotectant concentrations on immature oocyte vitrification

The aim of this study was to determine the effectiveness of using two different concentrations of cryoprotectants for the vitrification of immature swine oocytes. A total of 1394 oocytes were vitrified in super fine open pull straws, using two experimental designs. In experiment A the eggs were preserved stepwise in 15% (pre-vitrification solution) and 40% (vitrification solution) ethylene glycol, a permeating agent, combined with trehalose, a non-permeating agent (0.25 M and 0.5 M respectively). In the second experiment the concentration of the ethylene glycol was 20 and 50% and the trehalose concentrations were 0.5 and 0.75 M. After fluorescent staining, with fluorescein diacetate and propidium iodide, the cells were examined to test their viability by exposing them to the microscope's UV light. The results show that the increased concentration of cryoprotectants did not increase the rate of viable oocytes. The differences between two experiments are extremely significant (p