Method for increasing sheep cloning efficiency

Abstract

The invention discloses a method for increasing the cloning efficiency by increasing the embryo transplantation lambing percentage and survival rate, belonging to the field of embryo transplantation methods. The method comprises the following steps of: transplanting embryos with the embryonic ages 24-72 hours and uniform cleavage into synchronous estrus female sheep after transplantation activation, wherein 10-15 embryos are transplanted into every sheep; performing pregnancy management on female sheep which do not return to estrus within four continuous sexual periods after surgery; performing caesarean operation on surrogacy female sheep which surpass an expected date of childbirth by 5 days and of which the fetus body forms are too large; strictly controlling the nursing ambient temperature of borne lambs at 21-23 DEG C; and feeding the lambs with colostrum of healthy female sheep. Due to the adoption of the method provided by the invention, the pregnancy rate, lambing percentage and lamb survival rate of cloned sheep can be increased remarkably. After operation is performed in strict accordance with the invention, the pregnancy rate of cloned sheep is up to 30 percent, the lambing percentage is up to 31.67 percent, and the survival rate is up to 63 percent. The method for increasing the sheep cloning efficiency disclosed by the invention has wide application prospect.

Description

technical field [0001] The invention relates to a method for improving sheep cloning efficiency, in particular to a method for improving cloning efficiency by increasing embryo transfer lambing rate and survival rate, and belongs to the field of embryo transfer. Background technique [0002] At present, the birth rate after cloned embryo transfer is less than 10% on average, and the fetal abnormality, miscarriage and perinatal mortality rate are high, and the mortality rate in one week after birth can reach 100% (Westhusin, M.E., C.R.Long, T.Shin.Cloning to reproduce desired genotypes. Theriogenology, 2001, 55:35-49). Wilmut adopts mammary gland epithelial cells, fetal fibroblasts cultured in vivo, fetal fibroblasts cultured in vitro, and the cloned sheep birth rates obtained are respectively 3.4%, 5.9% and 16.6% (Wilmut I., Schnieke A.E., Mcwhir J., et al. Viable offspring derived from fetal and adult mammalian cells. Nature, 1997, 385: 810-813). There are many studies on...

AI Technical Summary

Problems solved by technology

There are many studies on the low birth rate and survival rate of sheep cloned by somatic cell nuclear transfer, most of which focus on the effects of in vitro culture on embryonic gene mutations, genome spatiotemporal expression, and uncontrolled fetal growth regulation and abnormal development (Farin P.W., Croiser A.E. and Farin C.E.Influence of in vitro systems on embryo survival and fetal development in cattle. Theriogenology, 2001, 55:151-107; Thompson J.G.Comparison between in vivo-derived and in vitro-produced preelongation embryos from domestic ruminants.Reprod 1 Fertil ; 9:341-54), but the reduction of pregnancy rate and survival rate of cloned sheep due to inadequate work of transplantation, midwifery and childcare cannot be ignored

Because the birth rate and survival rate of somatic cell nuclear transfer cloned sheep are very low, there is not a lot of facts as a basis to formulate a feasible plan for embryo transfer, delivery and childcare of somatic cell nuclear transfer cloned sheep. The work of embryo transfer, midwifery, and childcare has not been described in detail, especially the work of midwifery and childcare of lambs after birth is a big gap. Since the first somatic cell cloned sheep in China was born in this laboratory in 2007, it has been In the research work of somatic cell nuclear transfer cloned sheep, the technical level has been continuously improved, and a set of effective cloned sheep embryo transfer and birth care programs have been explored