Cumulus Cell and Oocyte Gene Expression in Prepubertal Gilts and Sows Identifies Cumulus Cells as a Prime Informative Parameter of Oocyte Quality

Cumulus cells (CCs) are pivotal during oocyte development. This study aimed to identify novel marker genes for porcine oocyte quality by examining the expression of selected genes in CCs and oocytes, employing the model of oocytes from prepubertal animals being of reduced quality compared to those from adult animals. Total RNA was extracted either directly after follicle aspiration or after in vitro maturation, followed by RT-qPCR. Immature gilt CCs accumulated transcripts, involved in L-carnitine biosynthesis, to a 14.8-fold higher level ( < 0.05) relative to sows, while for , participating in fatty acid oxidation, the level was 0.48 ( < 0.05). While showing no differences between gilt and sow CCs after maturation, and levels in oocytes were higher in gilts at both time points. The apparent delayed lipid metabolism and reduced accumulation of and transcripts in gilt CCs after maturation, implying downregulation of glycolysis and the pentose phosphate pathway, suggest gilt cumulus-oocyte complexes have inadequate ATP stores and oxidative stress balance compared to sows at the end of maturation. Reduced expression of and higher expression of in CCs before maturation and higher expression of and after maturation are new potential markers of oocyte quality.