绵羊胚胎移植研究进展

概述了绵羊胚胎移植技术的研究进展，包括同期发情，超数排卵，胚胎的收集与移植，胚胎冷冻，卵母细胞的体外成熟，体外受精，胚胎的体外培养，核移植等技术的最新研究进展与存在的问题。     

绵羊胚胎移植研究进展

本文概述了绵羊胚胎移植技术的研究进展,包括同期发情、超数排卵、胚胎的收集与移植的最新研究状况与存在的问题。     

滨州绵羊冷冻胚胎移植试验研究

该项成果通过引进德国肉用美利奴绵羊冷冻胚胎29枚,用山东地方良种洼地绵羊作受体,共移植受体母羊20只,二情期不返精率65％（13．20）,产出活羔11只,产羔率55％（11／20）。     

绵羊冷冻胚胎移植试验

绵羊冷冻胚胎有枚浆冻前Ａ级胚胎解冻后,胚胎等级有所下降,可用胚率为７７．９％,Ａ、Ｂ级胚移植妊娠率分别为３３．３％（１８／５４）和１６．７％（１／６）,差异不显著（Ｐ〉０．０５）;桑椹胚、早期囊胚、中期囊胚、扩张囊胚移植妊娠率分别为２０．８％（５／２５）、４２．９％（６／１４）、３５．７％（５／１４）５ ３７．５％（３／８）,囊胚期胚胎移植妊娠率较高,但差异不显著（Ｐ〉０．０５）     

肉用绵羊胚胎移植技术推广应用效果

文章宗旨是进行进口肉用绵羊胚胎移植,为肉用绵羊生产提供更多的种羊,促进肉用羊产业发展.采用CIDR+FSH方法,对20只萨福克羊进行超数排卵处理,超排有效率100％,平均排卵点12.47个/只,平均采胚10.68枚/只,最高个体采胚数23枚;采用CIDR+PMSG方法,对160只本地绵羊进行同期发情处理,24h内同期发情率为98.10％;胚胎移植后两个情期不返情率(妊娠率)69.03％,实际产羔率66.45％.     

针刺治疗卵巢疾病及对生殖内分泌激素调控的研究进展

针灸学是我国传统中医学的一支奇葩,应用针刺腧穴治疗疾病具有悠久的历史,长期以来积累了丰富的经验.尤其在应用针刺治疗卵巢疾病方面,取得了相当好的效果.近年来,随着对针刺腧穴调控雌性生殖内分泌功能研究的不断深入,在其机理方面的研究,引起了国内外许多专家、学者的广泛关注,也取得了长足进展,现就近年来针刺腧穴治疗卵巢疾病及对雌性生殖内分泌激素调节的研究概况综述如下.     

青海高原地区应用绵羊胚胎移植技术的效果分析

采用同期发情+超排对12只特克塞尔羊、无角陶赛特羊进行处理;同时采用自然发情+超排对12只德国肉用美利奴母羊进行处理。结果表明:采用同期发情+超排处理,每只特克塞尔母羊平均获卵胚8.7枚,获受精卵数7.1枚;陶赛特母羊平均获卵胚数1.8枚,获受精卵数1.8枚(P<0.01)。德国肉用美利奴供体母羊的平均获胚数13.5枚,可用胚8.7枚,可用胚率67.0%(P<0.01)。对85只受体绵羊进行同期发情处理,结果表明,处理后同期发情率达88.2%。将12枚可用胚胎移入11只受体,其中10只受体移入单胚,1只受体移入双胚,移植成功率达83.3%(P<0.01)。对62只自然发情的受体母羊进行胚胎移植,结果表明,移植2枚胚胎受体母羊的受胎率比移植1枚的要高34.0%(P<0.01)。     

青海高原地区应用绵羊胚胎移植技术的效果分析

采用同期发情+超排对12只特克塞尔羊、无角陶赛特羊,采用自然发情+超排对12只德国肉用美利奴母羊进行处理。结果表明:采用同期发情+超排处理,平均每只特克塞尔母羊获卵达8.7枚,平均获受精卵数7.1枚;陶赛特母羊平均1.8枚,受精卵数7枚,平均获受精卵数1.8枚(P<0.01)。德国肉用美利奴羊供体母羊的平均获胚数可达13.5枚,可用胚达8.7枚,可用胚率(%)迭67.0%(P<0.01)。对85只受体绵羊进行同期发情处理结果表明,处理后同期发情率达88.2%。将12枚可用胚胎移入10只受体,其中11只受体移入单胚,1只受体移入双胚,移植成功率达63.3%(P<0.01)。对62只自然发情的受体母羊进行胚胎移植,结果表明,移植2枚胚胎,受体母羊的受胎率比移植1枚的要高34%(P<0.01)。同期发情时间差异为±0d,妊娠率达100%,而时间差异为±0.5d的为66.67%(P<0.01)。对母羊发情时间与超排效果的关系分析结果表明,撤栓后24h内,或为注射FSH后第1天,标准时间内排卵(≤±4h)的母羊占64%,延时8 h以内排卵的占27%,提早或延时1.0h~1.5h排卵的占9%。     

肉用绵羊胚胎移植技术的研究

胚胎移植是一项现代繁殖生物工程技术之一 ,1999～ 2 0 0 1年我们采用FSH递减量法对兵团肉用种羊场 14只萨福克 ,陶赛特、夏洛莱母羊进行超排处理 ,其最佳比例是肉用绵羊 :细毛羊为 1:4～ 6,通过移植进行纯繁 ,提高羔羊成活率 ,降低成本。     

胚胎移植试验羊群发情规律的研究

为了有效提高绵羊体细胞克隆和转基因等研究工作的效率,缩短胚胎移植试验羊群中空怀个体的利用周期间隔,试验对采用不同移植方法的胚胎移植受体及供体绵羊进行了移植前后的发情规律研究。结果表明:采用自制孕激素海绵栓和进口阴道孕激素释放装置(CIDR)对绵羊进行同期发情处理时发情率均接近90%,且92%以上的个体发情起始时间均集中在撤栓后24～48 h。在胚胎移植试验结束后,未参加胚胎移植个体和子宫角法未移植受体第2情期发情起始时间主要集中在上次发情后的14～20 d,而输卵管法未移植受体和输卵管法冲卵供体的发情时间则比较分散,呈现明显延后状态。未参加胚胎移植个体和子宫角法未移植受体人工授精后的受胎率接近往年羊场的平均水平,输卵管法未移植受体的受胎率略有下降,且输卵管法冲卵供体的受胎率明显降低。     

Use of oxytocin to attain cervical dilation for transcervical embryo transfer in sheep

The aim of this work was to determine whether a cervical dilation protocol (CDP) composed of only oxytocin can be used to perform transcervical (non-surgical) embryo transfer in sheep (NSET) without affecting the viability of the corpus luteum (CL). Likewise, we evaluated whether a cervical transposing test with a Hegar dilator (CT Hegar test), performed at oestrous time, could be used to screen ewes for NSET (greater or lower chances to transpose the cervix). For that, oestrous and ovulation synchronization was performed in 25 Santa Inês ewes to induce the dioestrous condition. Animals went through the following CDP in a crossover design: E + OX, oestradiol benzoate (100 µg intravenously [IV]) and oxytocin (100 IU IV); OX, oxytocin (100 IU IV); and SAL, saline solution (IV). Using a Hegar dilator, cervical transposing attempts were performed at oestrous (D0) and dioestrous time (D8). The viability of the CL (morphology, luteal blood flow and progesterone values) was evaluated by ultrasonography (colour Doppler and B-mode) and by serum progesterone measurement from D7 to D13. The cervical transposing rate was lower for the SAL group (64%; 16/25; p < .05) and did not differ between the E + OX (88%; 22/25, p > .05) and OX (84%; 21/25, p > .05) groups. No treatment affected the CL viability. The CT Hegar test showed a high sensitivity (85.7%–93.3%), satisfactory accuracy (72%–84%), low false-negative rate (6.7%–14.6%), but high false-positive rate (46%–66.7%). In conclusion, a CDP protocol composed exclusively of oxytocin can lead to good cervical transposing rates and does not affect the viability of the CL. In addition, a screening test (CT Hegar) performed at oestrus can identify ewes for which cervical transposing will likely not occur at NSET.     

Effect of flunixin meglumine treatment during and after embryo transfer on the pregnancy rate in cattle

This study aimed to determine the effect of flunixin meglumine treatment during and after the transfer of in vivo produced embryos to Angus (cows) and Holstein (cows and heifers) breeds of cattle on pregnancy rate. Holstein cows were used as donors in the study. A double dose of prostaglandin F2α was administered to the recipient animals for synchronization. Uterine flushing was performed in donors on day 7 after artificial insemination. A total of 295 transferable embryos were obtained. These embryos were transferred to Angus cows (n = 85), Holstein heifers (n = 80) and Holstein cows (n = 130). After the transfer, these animals were divided into three subgroups. The first subgroup (TI) was administered flunixin meglumine during embryo transfer, and the second subgroup (TII) was administered flunixin meglumine both during embryo transfer and on days 8 and 9 after the transfer. The third subgroup (TIII) was not administered anything and it was considered the control group. Pregnancy examination of the recipients was performed on days 30–35 after the transfer using real-time ultrasonography. The pregnancy rates after embryo transfer were found to be 43.52% in Angus cows, 42.5% in Holstein heifers, and 24.61% in Holstein cows (p < .05). When the animals were not classified according to breed, the pregnancy rates in subgroups TI, TII and TIII were found to be 29.29%, 45.10% and 29.79%, respectively (p < .05). In addition, the pregnancy rates were higher in TII and TIII subgroups of Angus cows and Holstein heifers compared to that of Holstein cows (p < .05). As a result, the pregnancy rates obtained after embryo transfer in Angus cows and Holstein heifers were found to be higher than that in Holstein cows. In addition, it was concluded that the administration of flunixin meglumine during and during/after embryo transfer has a positive effect on pregnancy rates in Angus cows and Holstein heifers.     

胚胎质量和发育阶段对奶牛胚胎移植妊娠率的影响

[目的]为了评估胚胎质量和发育阶段对奶牛胚胎移植妊娠率的影响。[方法]使用63头青年奶牛作为供体进行超数排卵,评估回收胚胎质量和发育阶段。选择334头青年奶牛作为受体鲜胚移植不同质量和发育阶段胚胎。对胚胎质量分布、发育阶段分布、不同质量胚胎和不同发育阶段胚胎移植30 d妊娠率进行统计分析。[结果]可用胚胎中A级胚胎比例(60.78%)显著高于B级和C级胚胎比例(36.70%和2.52%)(P<0.05);致密桑椹胚比例(54.36%)显著高于早期囊胚,囊胚和扩张囊胚比例(18.35%,25.0%和2.29%)(P<0.05)。A级和B级胚胎移植30 d妊娠率(63.55%和64.35%)显著高于C级胚胎移植30 d妊娠率(44.44%)(P<0.05);致密桑椹胚、早期囊胚、囊胚和扩张囊胚移植30 d妊娠率差异不显著(P<0.05),早期囊胚、囊胚移植30 d妊娠率高于致密桑椹胚、扩张囊胚移植30 d妊娠率(P<0.05)。[结论]选择不同发育阶段的A级和B级胚胎能够获得较高胚胎移植妊娠率,增加早期囊胚和囊胚阶段胚胎移植数量能够提高胚胎移植妊娠率。     

Evaluation of the factors that affect the pregnancy rates during embryo transfer in beef heifers

The aim of this study was to evaluate the effects of the transfer side, transfer location, cervix transfer score, type and diameter of corpus luteum (CL) during embryo transfer on pregnancy rates in beef heifers. Progesterone-based synchronization and superovulation protocol were applied to Simmental cows used as donors (n = 168). Uterine flushings were performed on day 7 following artificial insemination. Obtained Code I (excellent or good) and II (fair) quality embryos were transferred to recipient beef heifers (n = 561). During embryo transfer, side of transfer (right or left), transfer location (the cranial or middle third of uterine horn), cervix transfer score (easy, moderate or difficult) and type (CLa, CLb and CLc) and diameter of CL were determined. Pregnancy rates following the transfer of Code I and II embryos were 44.66% and 33.07%, respectively (p < .05). The rates of pregnancy after transfers to the right and left uterine horn were 37% and 42.2%, respectively (p > .05). The pregnancy rates were 41.2%, 34.9% and 30.3% for cervix transfer scores as easy, moderate and difficult, respectively (p > .05). Pregnancy rates after transfer to the cranial third and middle third were 41.06% and 29.67%, respectively (p < .05). According to types of CL, pregnancy rates were 31.7%, 40.4% and 45.3% for CLa, CLb and CLc, respectively (p < .05). Moreover, it was found that as the CL diameter increased, the pregnancy rates increased. As a result, it was concluded that there was no effect of side of transfer and cervix transfer score, but embryo quality, transfer location, type and diameter of CL had significant effects on the pregnancy rate during embryo transfer in beef heifers.     

Achievements and future perspectives of embryo transfer technology in pigs

Commercial embryo transfer (ET) has unprecedented productive and economic implications for the pig sector. However, pig ET has been considered utopian for decades mainly because of the requirements of surgical techniques for embryo collection and embryo deposition into recipients, alongside challenges to preserve embryos. This situation has drastically changed in the last decade since the current technology allows non‐surgical ET and short‐ and long‐term embryo preservation. Here, we provide a brief review of the improvements in porcine ET achieved by our laboratory in the past 20 years. This review includes several aspects of non‐surgical ET technology and different issues affecting ET programmes and embryo preservation systems. The future perspectives of ET technology are also considered. We will refer only to embryos produced in vivo since they are the only type of embryos with possible short‐term use in pig production.     

Effect of semen and donor factors on multiple ovulation and embryo transfer (MOET) in sheep

Multiple ovulation and embryo transfer (MOET) is an important tool in the sheep industry for increasing numbers of genetically superior individuals. The objective of this study was to evaluate the effect of semen source (frozen or fresh), the number of embryo collection procedures for each donor (NECP), the season in which embryo transfer and collection was performed, and the age and breed of the donor, on the number of recovered embryos and pregnancy rates after embryo transfer. The Alamos Genetics’ flushing station database was used. This consisted of 140 embryo collection procedures, from 53 Dorper and White Dorper sheep donors, aged between one and eight years, totalling 1,200 collected embryos. Neither the number of retrieved embryos nor the pregnancy rate was affected by the semen preservation method (fresh or frozen), NECP or the age and breed of donor. The season did not affect the number of collected embryos but had a significant effect (p < 0.05) on the recipient pregnancy rate, with higher pregnancy rates reported in the winter (65.57% ± 25.33%) compared with spring (37.11% ± 33.27%), summer (29.95% ± 28.33%) or autumn (35.03% ± 31.66%). There is an estimated increase of 98.4% and 71.5% of embryos recovered in the spring and summer seasons, respectively, when winter is used as reference. The survival of embryos is significantly higher when implanted during the breeding season, more specifically in winter. Embryo collection can be carried out throughout the year in sheep, but there may be a marginal advantage in the use of superovulation and fresh embryo transfer programmes in the autumn and winter.     

FSH使用方法对无角道塞特绵羊超数排卵的影响

为探讨FSH的种类、剂量及注射次数和注射季节对绵羊超数排卵的影响,采用中国科学院动物所、宁波、加拿大生产的FSH对206只无角道塞特绵羊进行了超排处理,观察了供体发情率、回收胚胎数、可用胚胎数、退化胚及未受精卵比率以及供体的表现.结果,无论那种FSH,在适当的剂量范围都可有效进行超排,中国科学院FSH与宁波FSH联合使用可提高回收胚胎数和可用胚胎数;与6次递减注射相比,7次或8次递减注射的结果更为理想;秋季的超排效果优于春、夏和冬季.供体对激素处理表现复杂多变的超排反应,同时也出现卵子受精失败现象.结果表明,外源FSH只能在一定程度上控制超排反应,进一步的研究应考虑外源性FSH与内分泌反应的关系.     

Effect of oestrous synchrony between embryo donors and recipients,embryo quality and state on the pregnancy rate in beef cattle

This study aimed to evaluate the effect of oestrous synchrony between donors and recipients and the embryo quality on the pregnancy rate in beef cow recipients. The experiment was performed over two years at an embryo transfer (ET ) centre in Southern Brazil. Ninety Aberdeen Angus cows were subjected to superovulation (SOV ) protocols, resulting in the recovery of 1,048 transferable embryos. Eleven groups were formed with intervals of 6 hr, from ?30 to +30 hr, with respect to recipient versus donor oestrous detection. Evaluation of embryo quality was according to the IETS guidelines. The overall pregnancy rate was 52%. Effects related to donor and recipient oestrous synchronization on pregnancy rate were observed (p  =  .01), ranging from 36% to 50%. The embryo quality rate affected the pregnancy rate, where Grade I resulted in 57% and Grade III in 43% of pregnancy (p  <  .001). The embryonic state (frozen or fresh) showed no (p  >  .05) effect on pregnancy rate: 53% for fresh embryos and 44% for frozen embryos. The odds ratio for explanatory variables causing pregnancy indicated that Grade III embryos had 31% less chance of conception compared to Grade I. Thus, oestrous synchrony between donor and recipient, considering ±30 hr apart, can affect the pregnancy rate along with embryo quality.