SummaryThis study aimed to evaluate the relationship between antral follicular count (AFC) and ovarian volume (OV), preantral follicular population and survival, meiotic progression and ultrastructure of cumulus–oocyte complexes (COCs) after in vitro maturation. In experiment 1, the relationship between AFC and preantral follicle population and survival was evaluated by classical histology. In experiment 2, the relationship among AFC, OV, ability of oocytes to resume meiosis and ultrastructure of in vitro matured bovine COCs was studied. A positive correlation (P < 0.05) between AFC and the numbers of healthy primordial, degenerate and total follicles was observed, as well as with healthy secondary follicles and total follicles. The numbers of grades I and II oocytes in ovaries of high AFC class were higher compared with those with intermediate or lower AFC. After in vitro maturation, COCs from ovaries of high AFC had a higher percentage of oocytes in metaphase II compared with those of intermediate and low AFC (P < 0.0001). Ovaries of intermediate AFC had a higher percentage of oocytes in metaphase II compared with ovaries with low AFC (P < 0.0001). The proportion of oocytes in metaphase I, telophase I and anaphase I in COCs from ovaries of intermediate AFC (26.04%) was higher (P < 0.05) compared with that seen in COCs of ovaries with high (8.55%) and low (14.15%) AFC. No differences in the ultrastructure of oocytes were seen. In conclusion, after in vitro maturation, cow ovaries with high AFC have higher numbers of oocytes that reach in metaphase II (MII), but they also have higher numbers of degenerated primordial and primary follicles.

中文翻译：

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体外成熟牛卵丘-卵母细胞复合物的窦卵泡计数及其与卵巢体积、窦前卵泡数量和存活、卵母细胞减数分裂进程和超微结构的关系

摘要本研究旨在评估窦卵泡计数（AFC）与卵巢体积（OV）、窦前卵泡数量与存活率、减数分裂进程和卵丘-卵母细胞复合物（COCs）超微结构之间的关系。体外成熟。在实验 1 中，通过经典组织学评估 AFC 和窦前卵泡群与存活率之间的关系。实验二，AFC、OV、卵母细胞减数分裂恢复能力与卵母细胞超微结构的关系体外研究了成熟的牛 COC。正相关（磷< 0.05) 观察到 AFC 与健康的原始、退化和总卵泡的数量以及健康的次级卵泡和总卵泡的数量之间。与中、低AFC相比，高AFC卵巢中I级和II级卵母细胞的数量更多。后体外成熟时，来自高 AFC 卵巢的 COC 在中期 II 的卵母细胞百分比高于中等和低 AFC 的卵巢。磷< 0.0001)。与低 AFC 的卵巢相比，中间 AFC 的卵巢在 II 期的卵母细胞百分比更高（磷< 0.0001)。中期AFC卵巢COC中中期I、末期I和后期I的卵母细胞比例（26.04%）较高（磷< 0.05) 与高 (8.55%) 和低 (14.15%) AFC 的卵巢的 COC 相比。未观察到卵母细胞超微结构的差异。总之，经过体外成熟时，具有高 AFC 的奶牛卵巢具有更多数量的卵母细胞，这些卵母细胞到达中期 II (MII)，但它们也具有更多数量的退化的原始和初级卵泡。