Abstract
BACKGROUND AND AIM: Porcine follicular fluid (pFF) is frequently used to mimic the follicular microenvironment during in vitro maturation (IVM) of oocytes. However, the influence of oxidative stress levels within pFF on oocyte quality and embryo development remains unclear. This study aimed to investigate how varying oxidative stress index (OSI) of pFF affect porcine oocyte meiotic progression, fertilization, and embryonic development during IVM. MATERIALS AND METHODS: Oocytes were matured in IVM media supplemented with 30% pFF classified into low (OSI 19), medium (OSI 22), and high (OSI 25) oxidative stress groups, based on the ratio of diacron-reactive oxygen metabolites to biological antioxidant potential. Post-IVM, oocytes were assessed for meiotic stage, DNA fragmentation, reactive oxygen species (ROS), and glutathione (GSH) levels. Fertilization and embryo development outcomes were monitored following in vitro fertilization and culture. RESULTS: The OSI 19 group showed significantly higher maturation to the metaphase II stage and improved fertilization and blastocyst formation rates compared to OSI 22 and OSI 25 groups (p < 0.05). ROS and GSH levels were also significantly elevated in OSI 19 oocytes, without an increase in DNA fragmentation. Blastocysts from the OSI 25 group exhibited significantly higher DNA fragmentation index than those from the OSI 19 group (p < 0.05). CONCLUSION: The OSI of pFF modulates porcine oocyte competence and embryonic outcomes. Lower OSI is associated with enhanced antioxidant balance, meiotic maturation, and embryo quality. Monitoring pFF oxidative status may improve assisted reproductive outcomes in swine.