幼畜胚胎体外生产技术的研究进展

家畜JIVET技术采用外源促性腺激素处理幼龄母畜,诱导其卵泡大量发育,并与活体采卵、卵母细胞体外成熟、体外受精技术相结合体外生产胚胎,经胚胎移植后产生后代.本文综述了JIVET技术的研究现状,以及JIVET技术中幼畜的选择、超排方案、卵母细胞采集和体外培养的条件等,并进一步分析了JIVET技术生产胚胎的影响因素及存在的问题.     

羔羊胚胎体外生产技术研究进展

羔羊胚胎体外生产技术(JIVET)是对羔羊进行超数排卵后并采卵,在体外培养卵母细胞并进行体外授精,形成早期胚胎的一项技术。将JIVET技术与养羊业生产实际相结合,提高了母羊的繁殖效率,缩短世代间隔,加快了育种改良进程。笔者就JIVET技术的研究现状、操作步骤、存在问题和应用前景进行综述。     

牛羊幼畜胚胎体外生产技术的研究进展

幼畜胚胎体外生产技术(Juvenile in vitro embryo technology,简称JIVET)是集幼畜超排、活体采卵、卵母细胞体外成熟及受精、胚胎移植等技术为一体的胚胎生物技术体系,可以极大程度地缩短世代间隔,为胚胎生产及研究优良种畜提供技术指导。本文综述了JIVET的研究现状、操作流程,并进一步分析了JIVET中的影响因素,以及该技术目前所存在的问题和发展前景,为更好的生产应用提供一定的借鉴。     

幼畜胚胎体外生产技术研究进展

家畜JIVET技术采用外源促性腺激素处理幼龄母畜,诱导其卵泡大量发育,并与活体采卵、卵母细胞体外成熟、体外受精技术相结合体外生产胚胎,经胚胎移植后产生后代。本文综述了JIVET技术的研究现状、基本操作步骤,并进一步分析了JIVET技术中的影响因素,以及该技术所存在的问题和发展前景。     

幼畜超数排卵及卵母细胞体外成熟的研究进展

利用幼畜进行超数排卵,产生数量远高于成年母畜生产的窦状卵泡,结合活体取卵、卵母细胞体外成熟和体外受精等技术,大量生产体外胚胎,并移植至成年代孕母畜子宫内,迅速获得众多后代个体的系统工程,被称为幼畜体外胚胎移植技术(Juvenile in Vitro Embryo Transfer, JIVET)。该技术能最大程度地缩短世代间隔,加速遗传选育进度,可为胚胎干细胞、动物克隆和转基因动物制备等研究提供丰富的胚胎试验材料。JIVET技术成败的关键在于幼畜的超数排卵和体外成熟环节。该文综述了幼畜超数排卵的生理基础、幼畜的超数排卵效果;同时从卵泡液微环境、卵丘细胞状态、卵母细胞的细胞质和细胞核成熟以及体外成熟的优化方案等方面介绍了幼畜卵母细胞体外成熟的研究进展。     

羔羊超数排卵及体外胚胎生产技术的研究与应用进展

幼畜超数排卵及体外胚胎生产技术(JIVET)技术,是集幼畜超排、活体采卵、卵母细胞体外成熟、体外受精、胚胎体外培养和移植等技术为一体的新型生物技术体系。因其能快繁优秀种畜、缩短育种世代间隔、保护遗传资源等优点具有广阔的应用前景。本文综述了羔羊JIVET技术的原理、基本操作步骤和研究现状,分析了羔羊应用JIVET技术效果、影响因素、存在的问题和发展前景。     

羔羊诱导卵泡发育及其应用的研究进展

幼畜体外胚胎移植(Juvenile In Vitro Embryo Transfer,JIVET)技术是利用幼畜对外源激素敏感的生理特点,采用外源促性腺素诱导幼畜卵泡超数发育,结合卵母细胞体外成熟、体外受精和胚胎移植等技术生产后代,该技术体系的研究与应用可以充分发挥优秀母畜繁殖潜能,快速扩繁良种畜群。近年来,国内外对绵羊JIVET技术研究比较多,但应用JIVET技术生产体外胚胎的效率低下、效果不稳定仍然是一个普遍问题。迄今为止,大多数的研究致力于加强供体羔羊选择、优化激素处理方案以及提高羔羊卵母细胞体外发育能力等方面。本文综述了羊JIVET技术的原理与最新研究进展以及影响JIVET技术效率所存在的内因和外因,旨在为深层次探索羔羊卵子发生和卵泡发育调控机制提供理论依据,促进JIVET技术的研究与应用。     

牛羊繁育提速技术在京成功 绵羊繁育效率比常规胚胎移植提高20倍

从澳大利亚引进的新一代牛羊快速繁育技术-牛羊幼畜超排技术(JIVET技术),在北京创新科农农牧科技有限公司香河基地试验成功。这一技术将大大加速我国牛羊育种进程和优良种畜的扩繁。JIVET技术是集羔羊的超数排卵、卵母细胞体外成熟、体外受精、胚胎体外培养和胚胎移植等技     

犊牛胚胎体外生产技术研究进展

本文综述了犊牛胚胎体外生产JIVET技术的目的和意义,并分析了犊牛JIVET技术中的影响因素及存在的问题。     

幼龄杜泊羊胚胎体外生产技术的研究

为探讨幼龄杜泊羊胚胎体外生产技术(JIVET),给幼龄杜泊羊卵巢卵泡的利用提供技术支撑,试验采用促卵泡素(FSH)和孕马血清(PMSG)对4~8周龄杜泊羊进行诱导、活体采集卵母细胞、卵母细胞体外成熟-受精-受精卵培养及2~4细胞期受精卵移植研究。结果表明:从8只4~8周龄杜泊羊中采集到可用卵母细胞585枚,平均73.13枚/只;获得2~4细胞期受精卵346枚,卵裂率59.15%;将77枚2~4细胞期体外受精卵移植于17只受体母羊的输卵管壶腹部,7只母羊受孕,产羔13只,受胎率41.18%。说明采用4~8周龄杜泊羊胚胎体外生产技术可作为JIVET的有效技术。     

Developmental Capabilities of Embryos Produced In Vitro from Prepubertal Lamb Oocytes

Breeding from prepubertal females, known as juvenile in vitro embryo transfer (JIVET), reduces the generation interval and increases the rate of genetic gain in animal breeding programs. While the birth of the first lambs from prepubertal ewes occurred nearly 30 years ago; and there is considerable interest in the commercialization of this technology, its efficiency remains too low. The advent of in vitro production (IVP) of embryo resulted in the more widespread use of JIVET. Morphologic and metabolic differences coupled with reduced in vitro and in vivo development of oocytes derived from prepubertal animals have been reported. Research has been undertaken to optimize donor selection and hormone stimulation methods in an attempt to reduce the variability and increase the proportion of donors responding to hormone stimulation and increase oocyte developmental competence. Yet, this variation persists and the development of oocytes and embryos from prepubertal animals remains reduced when compared with adults. Recent improvements to JIVET, resulting from a modified hormone stimulation regime, have eliminated the failure of donors to respond to hormone stimulation, and increased both the number and developmental competence of oocytes harvested from very young prepubertal lambs. This increased efficiency has facilitated the incorporation of other reproductive technologies such as sperm sexing with JIVET, resulting in the birth of lambs of a pre-determined sex from prepubertal lambs. Increased rates of genetic gain in sheep breeding programs can be achieved by combining sexed sperm with oocytes obtained from lambs as young as 3–4 weeks of age. Continued increases in the efficiency of JIVET resulting from further improvements to hormone stimulation regimes and an increased understanding of the differences between oocytes from adult and prepubertal animals will result in the commercialization of this technology.     

羔羊超数排卵与胚胎体外生产技术研究进展

自从幼畜体外胚胎移植(JIVET)技术问世以来,因其在优秀种畜快繁、育种世代间隔缩短、遗传资源保护等方面具有广阔的应用前景,引起了很多科研机构的关注.为提高JIVET的生产效率,研究人员对该技术的多个环节进行了探索,但总体效率还不是很高.论文就羔羊超数排卵与胚胎体外生产技术实施中的关键环节,即羔羊超排供体的年龄、超排季...     

利用JIVET技术快速繁育萨福克羊的研究

JIVET技术是一项利用生殖激素刺激幼畜卵巢,从而使其快速、高效生产卵母细胞的技术。对4只1月龄萨福克幼羔注射FSH和PMSG激素,48 h后采用手术法抽取幼羔卵母细胞,并在体外成熟;将成熟的卵母细胞与精子进行体外受精,将正常分裂的2~8细胞胚胎移植到6只同期发情的受体小尾寒羊子宫内。结果显示,采用激素法处理萨福克幼羔后共采集到可用卵母细胞109枚,体外成熟培养后得到成熟卵母细胞79枚,成熟率为72.48%;体外受精后得到正常卵裂胚胎34枚,卵裂率为43.04%;胚胎移植后有3只受体母羊怀孕,受胎率为50%,并分娩得到3只萨福克幼羔。综上提示,利用JIVET技术可以缩短萨福克羊的繁育周期,从而加快其繁育速度。     

青春期前山羊卵母细胞体外生产胚胎的研究进展

青春期前卵母细胞的来源广泛,作为体外胚胎生产的试验材料,国外这方面的研究报道较多。作者就青春期前山羊卵母细胞体外成熟、成熟后细胞质中细胞器的变化情况、体外受精技术和胚胎体外培养等方面研究情况作一综述,供研究者参考。     

Production and lambing rate of blastocysts derived from in vitro matured oocytes after gonadotropin treatment of prepubertal ewes.

The aim of this study was to evaluate the effect of gonadotropin treatment on the in vitro maturation, blastocyst production, and developmental potential to term of oocytes collected from Sardinian neonatal and prepubertal ewes at 4 to 6 wk of age. Cumulus-oocyte complexes were recovered at 24 h after withdrawal of a 1/6th size progestagenated pessary from the donors, of which each received 120 IU FSH/LH and 400 IU PMSG in a single dose 36 h before sponge removal. Treated donors produced a greater (P<.01) number of oocytes per animal (86.2 +/-7.9) compared with slaughterhouse (untreated) prepubertal ewes (55.5+/-6.1) of the same age or with treated neonatal ewes (6.1+/-0.7) 10 d old. During oocyte maturation, there were no differences in the percentage of germinal vesicle break-down (78.08 vs. 74.24), metaphase I (89.13 vs. 87.18), and metaphase II (77.91 vs. 76.38) when evaluated after 8, 14, and 24 h of maturation, respectively, between oocytes from treated and slaughterhouse (untreated) prepubertal ewes. The embryo cleavage (71.1 vs. 73.7) and blastocyst rates (22.2 vs. 19.8) were similar in the treated and the untreated prepubertal ewes after transfer of in vitro matured oocytes into ligated oviducts of temporary recipients. The in vitro viability rates of vitrified blastocysts (81.2 vs. 76.9) and the in vivo survival rates (46.1 vs. 50.0) of embryos derived from in vitro matured and in vivo fertilized oocytes showed no difference. The data suggest that gonadotropin treatment increases oocyte production per animal but has no effect on oocyte quality because embryo production and lambing rates of blastocysts derived from in vitro matured oocytes were not markedly different from those derived from untreated prepubertal ewes of the same age.     

Genotyping strategies of selection candidates in livestock breeding programmes

Benefits of genomic selection (GS) in livestock breeding operations are well known particularly where traits are sex‐limited, hard to measure, have a low heritability and/or measured later in life. Sheep and beef breeders have a higher cost:benefit ratio for GS compared to dairy. Therefore, strategies for genotyping selection candidates should be explored to maximize the economic benefit of GS. The aim of the paper was to investigate, via simulation, the additional genetic gain achieved by selecting proportions of male selection candidates to be genotyped via truncation selection. A two‐trait selection index was used that contained an easy and early‐in‐life measurement (such as post‐weaning weight) as well as a hard‐to‐measure trait (such as intra‐muscular fat). We also evaluated the optimal proportion of female selection candidates to be genotyped in breeding programmes using natural mating and/or artificial insemination (NatAI), multiple ovulation and embryo transfer (MOET) or juvenile in vitro fertilization and embryo transfer (JIVET). The final aim of the project was to investigate the total dollars spent to increase the genetic merit by one genetic standard deviation (SD) using GS and/or reproductive technologies. For NatAI and MOET breeding programmes, females were selected to have progeny by 2 years of age, while 1‐month‐old females were required for JIVET. Genomic testing the top 20% of male selection candidates achieved 80% of the maximum benefit from GS when selection of male candidates prior to genomic testing had an accuracy of 0.36, while 54% needed to be tested to get the same benefit when the prior selection accuracy was 0.11. To achieve 80% of the maximum benefit in female, selection required 66%, 47% and 56% of female selection candidates to be genotyped in NatAI, MOET and JIVET breeding programmes, respectively. While JIVET and MOET breeding programmes achieved the highest annual genetic gain, genotyping male selection candidates provides the most economical way to increase rates of genetic gain facilitated by genomic testing.     

Activin‐A receptor expression patterns in prepubertal goat oocytes and derived embryos

This study examines the presence of activin IIA and IIB receptors (ActR‐IIA and ActR‐IIB) by Western blotting and immunocytochemistry in immature and IVM‐oocytes, 2 to 8‐cells embryos and blastocysts from prepubertal goats. Western blotting revealed that activin receptors are synthesized during oocyte maturation and embryo development. In the immunocytochemistry experiments, no immunostaining for either receptor was detected in oocytes while both receptors were immunolabelled in all the cells of cleaved embryos. In blastocysts, while ActR‐IIA expression appeared evenly distributed in the two cell lineages, inner cell mass and trophectoderm, the ActR‐IIB immunosignal was restricted mainly to the inner cell mass. Our findings reveal the presence of activin type II receptors (ActR‐IIA and ActR‐IIB) in in vitro matured prepubertal goat oocytes and blastocyst‐stage embryos. The expression of these receptors could be a key factor in understanding differences between competent and incompetent oocytes.     

Fertilization and blastocyst development in oocytes obtained from prepubertal and adult pigs

Polyspermic fertilization and embryo quality are important issues for the in vitro production of pig embryos. We hypothesized that oocyte donor (prepubertal gilt vs. sow) affects polyspermy and blastocyst development in vitro and that the sexual maturity of the oocyte donor affects the response to sperm concentration in the fertilization medium. In Exp. 1, oocytes of sows and gilts were mounted and stained 12 h after insemination to provide fertilization data. In Exp. 2, putative embryos were developed in vitro to 144 h post-insemination before mounting. In both experiments, cumulus-oocyte complexes (COC) were collected from ovaries of prepubertal gilts and adult sows. Sperm were added after maturation of COC for 40 to 44 h. Sperm from two boars at 0.5 to 5.0 x 10(6) sperm/mL was used for insemination. More (P < 0.01) monospermic fertilizations were observed in oocytes derived from gilts than for oocytes from sows. There were fewer (P < 0.02) penetrated sperm per fertilized oocyte in oocytes from gilts compared with sows. There were effects of semen donor (boar) on the percentage of monospermic (P < 0.01) and polyspermic (P < 0.002) fertilizations, and on the number of penetrated sperm/fertilized oocyte (P < 0.02). In Exp. 2, cleavage and blastocyst formation was evaluated at 2 and 6 d postinsemination, respectively. More (P < 0.001) blastocysts developed from sow-derived oocytes than from gilt-derived oocytes. More (P < 0.05) total cells per blastocyst were observed in embryos from sow-derived oocytes than from gilt-derived oocytes. Semen donor affected the percentage of oocytes cleaving (P < 0.02), and a boar x sperm concentration interaction affected (P < 0.05) the incidence of blastocyt formation. Results indicate that sexual maturity of the donor is not responsible for the high incidence of polyspermy in porcine in vitro fertilization. However, blastocyst development is improved by the use of oocytes from sows rather than from prepubertal gilts.