This study examined the effects of monosaccharide (glucose), disaccharide (sucrose) and polysaccharides (Ficoll and Lycium barbarum polysaccharide (LBP)) at different concentrations, using ethylene glycol (EG) as membrane-permeating cryoprotectant, on in vitro maturation of vitrified-thawed immature (GV) porcine oocytes. A total of 1145 oocytes were obtained by follicle aspiration from 496 ovaries of pigs slaughtered at a local abattoir and vitrified using a five-step method. After thawing and removal of cryoprotectant, oocytes were cultured for 44 h at 39 degrees C in a humidified atmosphere of 5% CO(2) in air. Oocytes were stained with DAPI and nuclear maturation was examined. The highest maturation rates were obtained in 1.5M glucose (8.62%), 0.75 M sucrose (20.0%), 3.0 g/ml Ficoll (13.79%) and 0.10 g/ml LBP (20.69%), respectively. The maturation rate using 0.75 M sucrose or 0.10 g/ml LBP was significantly higher compared to 1.5M glucose (P<0.05), but there was no significant difference from using 3.0 g/ml Ficoll (P>0.05). The percentage of oocytes reaching metaphase II (MII) stage in the cryopreserved groups was significantly lower than control (P<0.05). These results suggest that LBP is an effective non-permeating membrane cryoprotectant and 0.75 M sucrose or 0.10 g/ml LBP can be used as the vitrification solution for immature porcine oocytes.