Supplementing fibroblast growth factor 2 during bovine oocyte in vitro maturation promotes subsequent embryonic development

The overall objective of this work was to describe whether supplementing fibroblast growth factor 2 (FGF2) during in vitro maturation (IVM) affects cumulus and oocyte maturation and subsequent embryonic development. Supplementing 0.5, 5 or 50 ng/ml FGF2 to cumulus-oocyte complexes (COCs) increased the percentage of oocytes with extruded polar bodies after IVM. Supplementing FGF2 during COC maturation did not affect in vitro fertilization (IVF) rates but increased the percentage of blastocysts at day 7 post-IVF. Blastocyst cell number was not affected by FGF2 treatment. Supplementation with FGF2 did not affect cumulus expansion but reduced the proportion of apoptotic cumulus cells after IVM. The relative abundance of several cumulus cell transcripts associated with apoptosis and cumulus cell activity were not altered by FGF2 treatment. In summary, improvements in blastocyst development were achieved by FGF2 treatment during oocyte maturation. The reason for the enhanced oocyte competency remains unclear but may occur because of improvements in oocyte maturation and cumulus cell viability during IVM.