The oocyte diameter reaches maximum
(608.4 ± 66.8 mm) by the increase in acidophilic
yolk granules (Fig. 2g). The nucleus shrinks to
48.1 ± 17.8 mm in diameter and moves to the
periphery of the oocyte. Thereafter, germinal
vesicle breakdown (GVBD) occurs. Follicle cell
thickness is 2.3 ± 0.5 mm.