山羊胚胎分割及同卵双生试验

选择山羊晚期桑椹胚、囊胚、孵出囊胚和孵出增大胚泡,用简化分割法二分。将19对裸半胚移植于18只受体羊,结果有12只妊娠,其中两只胚胎消失,两只流产,其余8只足月分娩,共产半胚羔11只。晚期桑椹胚、囊胚、孵出囊胚和孵出增大胚泡各组的半胚发育为羔羊的发育率分别为12.5％(1/8)、20％(2/10)、25％(3/12)和62.5％(5/8)。前三组均未获得同卵双生羔羊。在第四组,将4对裸半胚移植于4只受体,有3只妊娠,足月分娩半胚羔5只,其中两对为同卵双生。本研究证明,对称分割山羊孵出增大胚泡,不仅其半胚在体内仍可继续发育形成正常胎儿,而且不装透明带移植其裸半胚,仍能获得较高的同卵双生率。山羊孵出增大胚泡更适宜用简化分割法分割。

THE PRODUCTION OF MONOZYGOTIC GOAT TWINS BY BISECTION OF EMBRYOS

Late morulae, blastocysts, hatched blastocysts and expanding hatched blastocysts from superovulated crossbred Saanen dairy goats and Shaanbei black goats were bisected with a microblade. Nineteen pairs of zona-free demi-embryos were transfered into 18 recipients, and 12 became pregnant. Two of the recipients which received bisected blastocysts lost their fetus at about day 60 of pregnancy, another two which received bisected hatched blastocysts aborted a single fetus at day 70 and 80 respectively. The remaining 8 recipients went to term, producing 11 half embryo kids. The success rate of demi-embryos reaching full term from morulae, blastocysts, hatched blastocysts and expanding hatched blastocysts was 12.5% ( 1/8 ), 20% ( 2/10), 25% ( 3/12), and 62.5% ( 5/8 ) respectively. No monozygotic twins were obtained in the first three groups. Three of the 4 recipients which each received a pair of demi-embryos from expanding hatched blastocysts became prognant, and 5 half embryo kids were obtained at delivery, including 2 pairs of monozygotic twins. The present study demonstrated that the expanding hatched blastocysts in goats are suitable for bisection by the simplified procedure to produce monozygotic twins.