Poor development of oocytes from prepubertal animals is a major factor that hinders the application of the technology, juvenile in vitro embryo transfer (JIVET). The aim of this study was to explore the possibility of improving the developmental competence of prepubertal oocytes by supplementing the oocyte in vitro maturation (IVM) medium with antioxidants and cytokines. Effects of two antioxidants, melatonin and sericin, were first examined. The results showed that melatonin had no significant beneficial roles on the lamb oocyte development, while 0.5% sericin supplemented during IVM significantly increased the blastocyst rate of lamb oocytes (46.5% vs 19.2% in control, P < 0.05). Next, effects of two kinds of combined supplements, insulin-transferrin-selenium (ITS) and fibroblast growth factor 2(FGF2)-leukemia inhibitory factor (LIF)-insulin-like growth factor1 (IGF1)(FLI) were tested. The results indicated that addition of FLI, but not ITS, in the IVM medium, significantly improved the blastocyst development of lamb oocytes (43.9% in FLI group vs 21.6% in control, P < 0.05). Further comparison showed that the developmental competence of oocytes was not significantly different among supplementation with sericin or FLI alone or both, all of which generated similar outcomes of blastocyst yield to the supplementation with adult follicular fluid. Finally, 27 blastocysts produced from lamb oocytes matured in the presence of sericin and FLI were transferred into 18 recipients, of which 9 were pregnant. This study suggests that the developmental competence of prepubertal oocytes can be improved by supplementing IVM medium with relevant agents like sericin and cytokines.

中文翻译：

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通过在体外成熟培养基中补充丝胶和成纤维细胞生长因子 2-白血病抑制因子-胰岛素样生长因子 1 组合来增强青春期前羔羊卵母细胞的发育能力

青春期前动物卵母细胞发育不良是阻碍青少年体外胚胎移植（JIVET）技术应用的主要因素。本研究的目的是探索通过向卵母细胞体外成熟 (IVM) 培养基补充抗氧化剂和细胞因子来提高青春期前卵母细胞发育能力的可能性。首先检查了两种抗氧化剂褪黑激素和丝胶的作用。结果表明褪黑激素对羊卵母细胞的发育没有显着的有益作用，而在 IVM 期间补充 0.5% 丝胶显着增加了羊卵母细胞的囊胚率（46.5% vs 19.2%，P < 0.05）。接下来是两种组合补品的效果，测试了胰岛素-转铁蛋白-硒（ITS）和成纤维细胞生长因子2（FGF2）-白血病抑制因子（LIF）-胰岛素样生长因子1（IGF1）（FLI）。结果表明，在 IVM 培养基中添加 FLI 而不是 ITS，显着改善了羊卵母细胞的囊胚发育（FLI 组为 43.9%，对照组为 21.6%，P < 0.05）。进一步的比较表明，单独补充丝胶或 FLI 或两者同时补充卵母细胞的发育能力没有显着差异，所有这些都产生了与补充成人卵泡液相似的囊胚产量结果。最后，由在丝胶和 FLI 存在下成熟的羔羊卵母细胞产生的 27 个囊胚被转移到 18 个受体中，其中 9 个已怀孕。