影响绵羊冻胚移植妊娠率的因素分析

本研究对胚胎质量、胚胎移植数量、胚胎发育阶段、冷冻方法、移植方法及饲养管理水平等因素对移植产羔率的影响进行研究,以提高绵羊胚胎移植效率。结果表明:采用1.5mol/L乙二醇做冷冻保护剂对胚胎进行常规冷冻,冻前A级胚胎冷冻/解冻后可用胚率、存活率、降级率均高于B级,差异极显著(P<0.01)。移植1枚冷冻解冻后A级、B级或2枚(A+B)胚胎的受体移植产羔率分别为44.48%、46.84%和44.81%。经χ2检验分析,三者之间无显著差异(P>0.05)。移植双胚的受体双羔率为22(%53/241),以胚胎为单位计算,产羔率仅为33.40%。A级囊胚和桑椹胚的产羔率之间无显著差异(P>0.05)。1.5 mol/L乙二醇常规冷冻保存的体内胚胎移植产羔率高于EFS40玻璃化冷冻保存,但经统计学分析,二者无显著差异(P>0.05)。子宫手术移植和腹腔内窥镜法子宫移植之间产羔率不具统计学差异(P>0.05)。在牧场条件下大规模移植的平均产羔率为43.95%,范围在20%￣70%之间,受体饲养管理水平对绵羊移植产羔率有较大影响。

Analysis to the Factors Affecting Pregnancy Rate of Sheep Fresh Frozen and IVP Embryos

To improve the transfer rate of sheep,we analysed embryo quality,the number of transfer embryo,the different stage of embryo,the method of freezing and transferring of embryo and the feeding level.The result indicated that embryos were frozen by conventional freezing method with 1.5 mol/L ethylene glycol(as the cryoprotectant).The useable rate and survival rate in grade A thawed embryo were higher than in grade B(97.72% > 73.7%,99.22% > 90.33%).We transferred 1 A grade thawed embryo(5 656),B grade embryo(792) and two(A+B) embryos(241) to recipients,the lambing rate of recipients was 44.48%,46.84% and 44.8%,respectively.No significant difference among three groups was compared with the χ2 text.The double lambing rate of recipients was 22%(53/241).When we counted by embryo,the lambing rate was 33.40%.There was no difference in lambing rate between the blastocyst grade A and morula grade A.The lambing rate of freezing with 1.5 mol/L EG was higher than with vitrification solution(EFS40) to in vivo embryos.No significant difference was found between the two groups by statistical analysis.There was no significant difference among nature oestrus,progesterone sponge plug + PMSG and PG(double times) on rate of lamb delivery(P > 0.05).The difference of uterine transplantation by surgery,tubal transplantation by surgery and uterine transplantation by laparoscope were not obvious(P > 0.05).The average rate of lamb delivery was 43.95% with thawed embryos frozen with 1.5 mol/L EG and laparoscopic transfer on a large scale,the range being from 20% to 70%.The lambing rate of recipients was influenced significantly by the level of feeding and management of recipients.We needn't observe the receptor after combinated laparoscope technology with progesterone sponge plug + PMSG,and it would contribute to development of embryo transfer in sheep on a large scale.