Effects of porcine follicle stimulating hormone, luteinizing hormone and estradiol supplementation in culture medium on ultrastructures of porcine cumulus oocyte complexes (pCOCs)

► The research studied the effects of pFSH, LH, and estradiol supplementation in culture medium on ultrastructures of porcine cumulus oocyte complexes (pCOCs) using transmission electron microcopy (TEM) and inverted microscopy. ► In conclusion, reproductive hormones can be used to induce immature oocyte complexes with intact cumulus cell layers (Type I) and multi cumulus cell layers (Type II) to further develop until maturation in in vitro condition. ► Changes of cumulus cells morphology were a sign of the beginning of oocyte maturation. ► From this findings, it implies that the granular substance at the end point of CCs that stick into zona pellucida of the oocyte contain OMI.