In vitro culture of cumulus–oocyte complexes from early antral follicles in prepubertal and adult ewes

Fertility preservation in adult livestock can be achieved by culturing growing oocytes from EAFs, a stage characterized by a small fluid-filled cavity. Still, its effectiveness in prepubertal animals remains uncertain. This study compared the quality and growth of oocytes from adult and prepubertal sheep. After 5 days in culture, oocytes from adult sheep showed better growth, structure, and cell-to-cell communication. In contrast, those from prepubertal sheep grew less but showed higher energy activity and early signs of maturation. These findings reveal clear age-related differences and suggest that current methods may need adjustments for younger animals. This work supports the development of better fertility preservation strategies for immature livestock.