[目的]研究牛活体采卵-体外受精(ovum pick-up and in vitro fertilization,OPU/IVF)体系,建立高效的牛体外胚胎生产系统。[方法]以从屠宰场采集的健康牛新鲜卵巢为试验材料,进行卵母细胞体外成熟、体外受精、体外胚胎培养相关条件的摸...[目的]研究牛活体采卵-体外受精(ovum pick-up and in vitro fertilization,OPU/IVF)体系,建立高效的牛体外胚胎生产系统。[方法]以从屠宰场采集的健康牛新鲜卵巢为试验材料,进行卵母细胞体外成熟、体外受精、体外胚胎培养相关条件的摸索,重点考查体外胚胎培养液中添加瘦素(leptin)对囊胚率的影响。选取13~15月龄健康荷斯坦奶牛及和牛各10头作为供体,进行活体采卵、卵母细胞体外成熟、体外胚胎生产,记录可用卵数及可用囊胚数,统计卵裂率、囊胚率;2个品种牛的体外冷冻胚胎解冻后,以荷斯坦奶牛为受体进行胚胎移植,移植后45 d统计妊娠率。[结果]添加30 U/mL的leptin可以显著(P<0.05)提高屠宰场来源牛体外胚胎的囊胚率。随机选择供体牛活体采卵,平均每头荷斯坦奶牛获得可用卵7.5枚,平均每头和牛获得可用卵8.1枚;荷斯坦奶牛及和牛的卵裂率分别为84.00%、82.71%,二者差异不显著(P>0.05)。体外培养条件下,平均每头荷斯坦奶牛获得可用囊胚4.3枚,平均每头和牛获得可用囊胚3.7枚;荷斯坦奶牛的囊胚率(57.33%)显著(P<0.05)高于和牛(45.68%)。体外胚胎解冻后移植,荷斯坦奶牛胚胎组的妊娠率为54.17%,和牛胚胎组的妊娠率为55.79%,二者差异不显著(P>0.05)。[结论]该研究建立的OPU/IVF体系可以有效提高优质母牛的利用效率,降低生产成本,为牛体外胚胎生产系统的优化提供了参考。展开更多
Animal taxonomy is a time-honoured discipline specializing in the classification of various species in the animal kingdom. Numerous zoologists have devoted their life-long careers to this subject and the voluminous li...Animal taxonomy is a time-honoured discipline specializing in the classification of various species in the animal kingdom. Numerous zoologists have devoted their life-long careers to this subject and the voluminous literature left by them has become one of immortal legacies of the human pursuit of the unknown. Today, a monumental work in the field, "Fauna Sinica", is making its debut as one of basic research results on the展开更多
a perfect piano performance needs excellent playing competence and outstanding artistic contents. Musical expression is the soul of piano playing. If a player lacks of abundant attainments and solid skills, it will be...a perfect piano performance needs excellent playing competence and outstanding artistic contents. Musical expression is the soul of piano playing. If a player lacks of abundant attainments and solid skills, it will be difficult for him/her to express the emotion of the opuses. As listeners’ aesthetic quality is increasing constantly, the emotional skill of piano playing is important. This paper expounded the definition and functions of musical expression, and discussed the methods for improving musical expression of piano from the perspective of listeners.展开更多
文摘[目的]研究牛活体采卵-体外受精(ovum pick-up and in vitro fertilization,OPU/IVF)体系,建立高效的牛体外胚胎生产系统。[方法]以从屠宰场采集的健康牛新鲜卵巢为试验材料,进行卵母细胞体外成熟、体外受精、体外胚胎培养相关条件的摸索,重点考查体外胚胎培养液中添加瘦素(leptin)对囊胚率的影响。选取13~15月龄健康荷斯坦奶牛及和牛各10头作为供体,进行活体采卵、卵母细胞体外成熟、体外胚胎生产,记录可用卵数及可用囊胚数,统计卵裂率、囊胚率;2个品种牛的体外冷冻胚胎解冻后,以荷斯坦奶牛为受体进行胚胎移植,移植后45 d统计妊娠率。[结果]添加30 U/mL的leptin可以显著(P<0.05)提高屠宰场来源牛体外胚胎的囊胚率。随机选择供体牛活体采卵,平均每头荷斯坦奶牛获得可用卵7.5枚,平均每头和牛获得可用卵8.1枚;荷斯坦奶牛及和牛的卵裂率分别为84.00%、82.71%,二者差异不显著(P>0.05)。体外培养条件下,平均每头荷斯坦奶牛获得可用囊胚4.3枚,平均每头和牛获得可用囊胚3.7枚;荷斯坦奶牛的囊胚率(57.33%)显著(P<0.05)高于和牛(45.68%)。体外胚胎解冻后移植,荷斯坦奶牛胚胎组的妊娠率为54.17%,和牛胚胎组的妊娠率为55.79%,二者差异不显著(P>0.05)。[结论]该研究建立的OPU/IVF体系可以有效提高优质母牛的利用效率,降低生产成本,为牛体外胚胎生产系统的优化提供了参考。
文摘Animal taxonomy is a time-honoured discipline specializing in the classification of various species in the animal kingdom. Numerous zoologists have devoted their life-long careers to this subject and the voluminous literature left by them has become one of immortal legacies of the human pursuit of the unknown. Today, a monumental work in the field, "Fauna Sinica", is making its debut as one of basic research results on the
文摘a perfect piano performance needs excellent playing competence and outstanding artistic contents. Musical expression is the soul of piano playing. If a player lacks of abundant attainments and solid skills, it will be difficult for him/her to express the emotion of the opuses. As listeners’ aesthetic quality is increasing constantly, the emotional skill of piano playing is important. This paper expounded the definition and functions of musical expression, and discussed the methods for improving musical expression of piano from the perspective of listeners.
