Barceló-Fimbres M, Campos-Chillón L F, Mtango N R, Altermatt J, Bonilla L, Koppang R, Verstegen J P
International Center for Biotechnology, MOFA Global, Verona, Wisconsin, USA.
Department of Animal Science, California Polytechnic State University, San Luis Obispo, California, USA.
Theriogenology. 2015 Jul 1;84(1):109-17. doi: 10.1016/j.theriogenology.2015.02.020. Epub 2015 Feb 28.
The present work evaluated the benefit of a novel shipping and maturation medium (SMM) not requiring a CO2 gas for maturation and subsequent embryonic development of slaughterhouse and ovum pickup (OPU) bovine cumulus-oocyte complexes (COCs). Four experiments were conducted. In experiment 1, COCs were maturated for 18 hours in SMM and then incubated for 6 hours in, or 24 hours in a conventional system (control). Experiment 2 compared maturation for 24 hours in SMM versus 24 hours in the control. Experiment 3 compared three different incubation temperatures (37 °C, 38 °C, and 38.5 °C) for COCs maturation in SMM. In experiment 4, COCs obtained from 166 OPU sessions (representing two dairy and two beef breeds) in two locations (Wisconsin and California) were matured in SMM or control and evaluated relative to embryo production and pregnancy rates. Frozen semen was used for all experiments. The results for experiment 1 showed that the blastocyst rate and total embryo production rate (TE, Day-7 morulae plus all blastocysts) were higher for SMM than those in the control. However, no differences were observed for cleavage rate or blastocyst stage. In experiment 2, the blastocyst rate and TE were higher for SMM than those in the control; however, there was no difference for cleavage rate, total cell number, blastocyst stage. In experiment 3, the cleavage rate was similar, but the blastocyst rate and TE were greater for 38.5 °C than those for 38.0 °C and 37.5 °C. For experiment 4, Wisconsin OPU-derived COCs had a greater cleavage rate, blastocyst rate, TE, and blastocyst stage for SMM versus control. There were no breed effects. For the California trial, OPU-derived COCs matured in SMM had similar cleavage and pregnancy rates at Day 35 but greater blastocyst rates and transferred embryos per session than the control, which resulted in 2.2 more pregnancies per OPU session. Holstein COCs had superior embryonic development but similar pregnancy compared with Jersey. We conclude that COCs matured in SMM had greater oocyte competence than the control. Also, maturation at 38.5 °C in SMM was optimal for embryonic development. In summary, SMM resulted in greater embryonic development, similar pregnancy rates, but higher pregnancies per OPU session than the conventional maturation system.
本研究评估了一种新型运输与成熟培养液（SMM）的益处，该培养液在屠宰场采集和经卵巢采卵（OPU）获得的牛卵丘-卵母细胞复合体（COC）的成熟及后续胚胎发育过程中无需二氧化碳气体。进行了四项实验。在实验1中，COC在SMM中成熟18小时，然后在常规系统中培养6小时（对照组）或24小时。实验2比较了在SMM中成熟24小时与在对照组中成熟24小时的情况。实验3比较了COC在SMM中成熟时的三种不同培养温度（37°C、38°C和38.5°C）。在实验4中，从两个地点（威斯康星州和加利福尼亚州）的166次OPU采集（代表两个奶牛品种和两个肉牛品种）获得的COC在SMM或对照组中成熟，并根据胚胎产量和妊娠率进行评估。所有实验均使用冷冻精液。实验1的结果表明，SMM组的囊胚率和总胚胎产量率（TE，第7天的桑葚胚加所有囊胚）高于对照组。然而，在卵裂率或囊胚阶段未观察到差异。在实验2中，SMM组的囊胚率和TE高于对照组；然而，在卵裂率、总细胞数、囊胚阶段方面没有差异。在实验3中，卵裂率相似，但38.5°C时的囊胚率和TE高于38.0°C和37.5°C时。对于实验4，来自威斯康星州OPU的COC，与对照组相比，SMM组的卵裂率、囊胚率、TE和囊胚阶段更高。不存在品种效应。对于加利福尼亚州的试验，在SMM中成熟的OPU来源的COC在第35天的卵裂率和妊娠率相似，但囊胚率和每次采集移植的胚胎数高于对照组，这使得每次OPU采集的妊娠数增加2.2例。与泽西牛相比，荷斯坦牛的COC具有更好的胚胎发育但妊娠情况相似。我们得出结论，在SMM中成熟的COC比对照组具有更高的卵母细胞发育能力。此外，在SMM中38.5°C下成熟对胚胎发育最为适宜。总之，与传统成熟系统相比，SMM能带来更好的胚胎发育、相似的妊娠率，但每次OPU采集的妊娠数更高。
