Prediction of oocyte developmental competence in ovine using glucose-6-phosphate dehydrogenase (G6PDH) activity determined at retrieval time

To determine whether G6PDH-activity measured by Brilliant Cresyl Blue known as BCB dye, predicts developmental competence within cohorts of ovine oocytes. Ovine oocytes were exposed to BCB staining and categorized into two groups: BCB+ (blue cytoplasm, low G6PDH-activity) and BCB- (colorless cytoplasm, high G6PDH-activity). After maturation in vitro, oocytes were subjected to fertilization followed by in vitro embryo culture. We observed a significant difference in oocyte diameter considering BCB+ and BCB- oocytes. BCB+ and Control groups showed significantly higher maturation rates compared to BCB- group. There were significantly more cleaved embryos in BCB+ and control groups than in BCB- group. Blastocyst rate was significantly higher for BCB+ group compared to control and BCB- groups with control group being significantly higher than BCB- group. G6PDH-activity is a strong predictive marker of oocyte competence and may be useful in identifying oocytes with a good prognosis for further develop.