Cryopreservation of gametes and embryos is used to maintain genetic diversity of domestic and wild felids. However, felid oocytes and preimplantation embryos contain large amount of intracellular lipids, which affect their cryosensitivity. The objective was to compare the effects of slow freezing and vitrification and to study lipid phase transition (LPT) during cooling in cat embryos. In vitro‐derived embryos were cultured 48 hr up to 4–8 cell stage, thereafter were either slow frozen or vitrified. Propylene glycol (PG) alone was used as a cryoprotective agent (CPA) for slow freezing, and a mixture of PG and dimethyl sulfoxide (DMSO) were used as CPAs for vitrification. After thawing/warming, embryos were in vitro cultured additionally for 72 hr. The total time of in vitro culture was 120 hr for all the groups including non‐frozen controls. Effects of both cryopreservation procedures on the subsequent embryo development and nuclear fragmentation rate in embryonic cells were compared. There was no significant differences among the percentages of embryos achieved morula and early blastocyst stage in frozen‐thawed group (36.4% and 20.0%), in vitrified‐warmed group (34.3% and 28.6%) and in controls (55.6% and 25.9%). Cell numbers as well as nuclear fragmentation rate did not differ in these three groups. Average lipid phase transition (LPT) temperature (T*) was found to be relatively low (–2.2 ± 1.3°C) for the domestic cat embryos. It is supposed that the low LPT of LDs may provide a good background for successful application of slow freezing to domestic cat embryos. Generally, our study indicates that slow freezing and vitrification are both applicable for domestic cat embryo cryopreservation.

中文翻译：

---

缓慢冷冻和玻璃化对家猫胚胎发育的影响

配子和胚胎的冷冻保存用于维持家养和野生猫科动物的遗传多样性。但是，猫卵母细胞和植入前胚胎含有大量的细胞内脂质，这会影响它们的冷冻敏感性。目的是比较缓慢冷冻和玻璃化的作用，并研究猫胚胎在冷却过程中的脂质相转变（LPT）。将体外培养的胚胎培养48小时，直至4-8个细胞阶段，然后缓慢冷冻或玻璃化。单独使用丙二醇（PG）作为冷冻保护剂（CPA）进行慢速冷冻，并使用PG和二甲基亚砜（DMSO）的混合物作为CPA进行玻璃化。解冻/加热后，将胚胎另外在体外培养72小时。包括非冷冻对照组在内的所有组的体外培养总时间为120小时。比较了两种冷冻保存程序对随后胚胎发育和胚胎细胞核碎裂率的影响。冻融组（36.4％和20.0％），玻璃化保温组（34.3％和28.6％）和对照组（55.6％和25.9％）达到桑ula胚和胚泡早期的胚胎百分比没有显着差异。 ）。在这三组中，细胞数量和核碎裂率没有差异。发现家猫的平均脂质相变（LPT）温度（T *）相对较低（–2.2±1.3°C）。可以认为，LDs的低LPT可能为成功将慢速冷冻应用于家猫胚胎提供了良好的背景。通常，