Reproduction Abstracts

Oocyte–cumulus communication is essential for COC metabolism and oocyte developmental competence. Although the oocyte appears not to be absolutely required for cumulus expansion in cattle, it is not clear whether it influences this process. We tested the effects of oocytectomy on expansion and glucose metabolism of bovine COCs submitted to in vitro maturation (IVM). Follicles 3–8 mm were aspirated from abattoir ovaries and grades 1 and 2 COCs were selected. ...

Introduction: The WNT signaling pathway plays important roles in sex determination and embryonic development. Previous results indicated that WNT4 is required for normal ovarian follicle development and fertility and that WNT4 and WNT5a play redundant roles in regulating oocyte entry into meiosis during embryogenesis, suggesting potential redundant roles of WNT4 and WNT5a in the ovary. The objective of this study was to determine the effect of granulosa cell-conditional knock-...

Introduction: Deoxynivalenol (DON) is a major mycotoxin found in animal feed, one of its major actions is to activate the ribotoxic stress response (RSR) in different cells types. DON has been shown to inhibit progesterone secretion from porcine granulosa cells, but its effect in the cow is unknown. The objective of this study was to determine the effects of DON on bovine granulosa cells in vitro.Materials and methods: Bovine granulosa cells fro...

Oocytes are arrested in prophase I until the LH surge, which stimulates an EGF-like growth factor signaling cascade critical for cumulus expansion, and releases meiotic arrest while inhibiting the expression of natriuretic peptide C (NPPC). In rodents, there is evidence that KIT ligand (KITLG) secreted from granulosa/cumulus cells may also enhance nuclear maturation of the oocyte. The objective of the present study was to measure the expression of KITLG in bovine cumulus–...