奶牛体外受精胚胎的性别控制研究

为加速母牛胚胎的生产,实现性控制胚胎产业化和体外扩繁优质品种的奶业工程发展,本研究在体外受精技术（in vitro fertilization,IVF）不断成熟和完善的基础上,通过对牛非性控IVF胚胎与常规人工受精体内胚胎移植的妊娠成功率及其两者出生后牛的性别比例进行比较分析,结果发现,两组妊娠成功率基本相同,且IVF胚胎出生的公牛比例高于体内胚;采用性控和非性控精液进行IVF试验,并对非性控IVF胚胎及性控IVF胚胎用牛Y染色体性别决定特异基因（SRY）核心序列进行分子生物学性别鉴定,结果显示,性控IVF胚胎的公牛比例显著低于普通IVF胚胎;此外,作者还比较了性控IVF与普通非性控IVF的囊胚发育率,结果显示两者并无显著差异。以上研究结果证明,体外扩繁优质良种母牛的奶业工程必须依靠性别控制体外授精技术来提高其效率和有效性。     

体外培养体系对牛体外受精胚胎性比的影响

研究了不同体外培养体系对牛体外受精胚胎性比的影响。结果表明，添加血清的2组培养系统中所得雄性囊胚与雌性囊胚的性比虽偏离了1：1，但差异不显著（P〉0．05），而总的体外胚胎的性比则显著偏离了1：1（P〈0．05）。这说明在体外培养系统中雄性胚胎比雌性胚胎发育能力更强，并且血清的存在对于雄性胚胎的发育有明显的促进作用。     

牛早期胚胎性别快速鉴别的研究

根据聚合酶链式反应中聚合酶的扩增特性,对PCR反应的循环参数进行研究,取消了PCR反应中延伸这1温度梯度,对2温度梯度PCR方法进行了单重PCR和多重PCR扩增研究,并采用2温度梯度多重PCR方法分别对牛基因组、成纤维细胞、胚胎样品进行了性别鉴别研究,建立了稳定、简便、快速的用于牛早期胚胎性别鉴别的2温度梯度PCR方法.同时还对2温度梯度PCR的扩增能力进行了研究,结果表明：2温度梯度PCR方法能够扩增片段的可能长度为633 bp.     

Apoptosis-independent Poor Morphology of Bovine Embryos Produced by Multiple Ovulation

In multiple ovulation and embryo transfer (MOET) programmes in cattle, a considerable number of morphologically poor-quality embryos continue to be produced; this is one of the limiting factors of the technique. Apoptosis has often been implicated in developmental arrest and fragmentation; these are regarded as poor traits of embryonic quality in mammalian pre-implantation embryos. In the present study, apoptosis was assessed in morphologically poor-quality embryos in comparison with good-quality embryos that were recovered from a MOET programme. Retarded embryos (two to 16 cell stage), morulae with severe fragmentation and morphologically good-quality morulae recovered from superstimulated cows at day 7 post-insemination were subjected to TdT-mediated dUTP nick-end labelling (TUNEL) and Hoechst staining. Cell nuclei that showed both TUNEL staining and apoptotic morphology were considered to be apoptotic. Apoptotic index (AI) was calculated as the percentage of apoptotic cells per embryo. Fifteen of 17 retarded embryos and 10 of 15 morphologically poor-quality morulae did not show signs of apoptosis. The mean AIs in the morphologically poor-quality embryos (two to 16 cell stage, 2.2%; poor morulae, 1.3%) were as low as that in the good-quality embryos (2.9%). These results suggest that another mode of developmental arrest and/or fragmentation that is independent of apoptosis occurs in morphologically poor-quality embryos recovered from MOET programmes.     

应用X精子冷冻精液生产体内性控胚胎的试验

采用CIDR FSH PG法对206头优秀荷斯坦供体母牛进行超数排卵,其中实验组73头超排后用X性控冷冻精液输精(每头3支),获可用胚310枚,头均可用胚4.25枚;对照组133头,采用常规冷冻精液输精(每头3支),获得可用胚787枚,头均可用胚5.92枚,差异不显著。结果表明,用已分离的X精子冷冻精液对超排母牛进行人工授精生产体内性控胚胎是可行的。     

牛精子体外获能的研究进展

文章从精子体外获能的分子机制和体外获能的影响因素等两个方面对牛精子体外获能的发展现状作了比较全面的概括.同时指出了各种处理精子方法的优缺点.并指出了牛精子体外获能的研究价值和意义.     

荷斯坦牛和西门塔尔牛冻精品质及其体外受精后早期胚胎发育的比较研究

为探讨荷斯坦牛和西门塔尔牛冻精的精液品质及体外受精后胚胎发育能力的差异,利用目测法、低渗膨胀法和考马斯亮蓝染色法评估了荷斯坦牛和西门塔尔牛冻精的活力、质膜完整率和顶体完整率,并比较了二者冻精体外受精后胚胎的卵裂率和囊胚率。结果表明,荷斯坦牛和西门塔尔牛冻精的活力(30.4%和27.2%)、质膜完整率(41.96%和36.22%)和顶体完整率(77.02%和73.02%)均无显著差异(P>0.05),但荷斯坦牛冻精体外受精后的卵裂率(57.5%和48.6%)和囊胚率(30.3%和23.2%)显著高于西门塔尔牛冻精(P<0.05)。提示,不同品种公牛精液体外受精后的发育能力有显著差异(P>0.05)。     

利用多重PCR技术鉴别牛早期胚胎性别研究

本研究利用一对根据牛Y-染色体特异重复序列设计的牛Y-染色体特异性引物和一对根据牛微卫星DNA设计的牛常染色体内标引物,通过对PCR反应体系中Mg^2＋浓度和PCR反应条件中退火温度的优化,建立了牛早期胚胎性别鉴定的多重PCR反应体系。     

利用牛Y染色体重复序列进行早期胚胎性别鉴定的研究

本试验利用Y染色体重复序列作为雄性特异性引物,以肿瘤坏死因子（TNF-α）为内标引物建立多重PCR体系,进行牛早期胚胎性别鉴定。共设计四对引物—Y染色体重复序列外引物和内引物,其大小分别为534bp和480bp;肿瘤坏死因子外引物和内引物大小分别为357bp和272bp。试验结果表明,优化后的多重PCR体系的灵敏度分别达到3个胚胎细胞,准确率100%,可以满足早期胚胎性别鉴定的需要。     

PCR法鉴别牛早期胚胎性别的研究进展

对PCR法鉴别动物胚胎性别的机理进行了分析,综述了近10年来相关操作技术的进展,包括早期胚胎取样、胚胎细胞DNA的提取、引物的设计、扩增条件的优化、扩增产物的检测和性控胚胎的冷冻等,并提出PCR法鉴别牛早期胚胎性别的前景与展望。     

PCR技术在牛早期胚胎性别鉴定中的应用

牛早期胚胎的性别鉴定已有十几年的发展历史,从早期的免疫学方法到胚胎细胞的染色体核型分析,取得了巨大的进展,但真正进入实用化阶段是PCR技术在牛早期胚胎性别鉴定中的应用.     

Insemination with Sex Sorted Fresh Bovine Spermatozoa Processed in the Presence of Antioxidative Substances

Flow cytometrically sex sorted spermatozoa are reduced in their fertilizing capacity, particularly when stored either in cooling extender or after freezing in liquid nitrogen. So far, preservation methods for sorted spermatozoa have differed only marginally from procedures used for unsorted semen. In the present study, a TRIS extender was modified to balance major cell damage caused by the sorting process and by liquid storage of the sorted spermatozoa. The new extender, containing a combination of antioxidants (AO) and bovine serum albumin (BSA), significantly increased the lifespan and fertilizing capacity of sex sorted spermatozoa. No significant differences were observed between unsorted controls and sorted samples for motility and status of sperm membranes as tested by fluorescein-isothiocyanat-peanut agglutinin/propidium iodide (FITC-PNA/PI). Acrosome integrity of spermatozoa was significantly better when semen was stored at 15 degrees C for 24 and 48 h in an extender containing AO with or without BSA as compared with controls (p < 0.05). There were no significant differences, in pregnancy rates of heifers inseminated at a natural oestrus, between unsorted controls (16/24, 66.7%) and both sorted groups (AO + BSA: 18/31, 58.1% and AO-BSA: 12/22, 54.5%). Additionally, it was shown for the first time that artificial insemination (AI) with liquid sexed bull spermatozoa stored for 72 h after sorting can result in pregnancy rates similar to AI with non-sorted semen.     

Correlation between the Cell Number and Diameter in Bovine Embryos Produced In Vitro

This study was designed to examine the effects of age and developmental stage of in vitro‐produced bovine embryos on the cell number of the embryos and to investigate the correlation between the cell number and diameter in the embryos. The diameter and cell number in blastocysts and expanded blastocysts collected on days 7–9 after in vitro fertilization (IVF) were examined. Although the diameters of the blastocysts collected on days 7 and 8 after IVF were smaller than those of the expanded blastocysts collected on day 9, the cell number in both types of embryos was similar. The cell numbers of the blastocysts and expanded blastocysts decreased with increasing embryo age. There were positive correlations between the cell number and diameter in bovine embryos at each stage collected on each day after IVF. However, the value of the correlation coefficient in the day‐9 expanded blastocyst group tended to be higher than that in the other groups. These results indicate that the cell number of in vitro‐produced embryos is affected by the embryonic stage and age. The diameter of the embryo may be potentially used for the viability testing of the expanded blastocysts collected on day 9 after IVF.     

体外生产的牛胚胎超微结构研究

利用两种常规体外培养系统研究了体外培养及不同培养条件对牛体外受精胚胎早期发育各时期超微结构的影响。结果显示:体外发育的牛胚胎在发育的各个时期(从原核期到囊胚)胞质中均含有丰富的脂滴,胚胎中特别是在桑椹胚及囊胚阶段可见到一些异常细胞。两系统下发育的胚胎中脂滴形态不同,从桑椹胚阶段开始,胚胎线粒体的发育在M199 BOEC FCS培养系统中明显滞后于其在SOFaa BSA培养系统中的对照。     

Beneficial Effect of Two Culture Systems with Small Groups of Embryos on the Development and Quality of In Vitro‐Produced Bovine Embryos

Currently, in vitro‐produced embryos derived by ovum pick up (OPU) and in vitro fertilization (IVF) technologies represent approximately one‐third of the embryos worldwide in cattle. Nevertheless, the culture of small groups of embryos from an individual egg donor is an issue that OPU‐IVF laboratories have to face. In this work, we tested whether the development and quality of the preimplantation embryos in vitro cultured in low numbers (five embryos) could be improved by the addition of epidermal growth factor, insulin, transferrin and selenium (EGF‐ITS) or by the WOW system. With this aim, immature oocytes recovered from slaughtered heifers were in vitro matured and in vitro fertilized. Presumptive zygotes were then randomly cultured in four culture conditions: one large group (LG) (50 embryos/500 μl medium) and three smaller groups [five embryos/50 μl medium without (control) or with EGF‐ITS (EGF‐ITS) and five embryos per microwell in the WOW system (WOW)]. Embryos cultured in LG showed a greater ability to develop to blastocyst stage than embryos cultured in smaller groups, while the blastocyst rate of WOW group was significantly higher than in control. The number of cells/blastocyst in LG was higher than control or WOW, whereas the apoptosis rate per blastocyst was lower. On the other hand, the addition of EGF‐ITS significantly improved both parameters compared to the control and resulted in similar embryo quality to LG. In conclusion, the WOW system improved embryo development, while the addition of EGF‐ITS improved the embryo quality when smaller groups of embryos were cultured.     

性控精液在牛体外性控胚胎生产中的应用

利用性控精液结合体外胚胎生产技术是获得预知性别后代的一种有潜在效率的方法.自20世纪90年代,利用流式细胞仪将X精子和Y精子分离开来,使畜牧生产性别选择的梦想变为现实,性控精液得到了极大的推广应用.本文重点阐述利用性控精液进行胚胎体外生产的研究和生产状况.     

Relationship between Oxygen Consumption and Sex of Bovine In Vitro Fertilized Embryos

The present study was conducted to examine the relationship between the oxygen consumption rate and sex ratio of bovine in vitro fertilized embryos on each day of blastocyst formation. The quality of blastocysts collected on day 7, 8, and 9 after in vitro fertilization (IVF) were categorized as ranks A and B (excellent and good, respectively) based on microscopic observation of the morphology. The oxygen consumption rate and sex of individual blastocysts were evaluated using two novel techniques: scanning electrochemical microscopy (SECM) and loop-mediated isothermal amplification (LAMP), respectively. The oxygen consumption rates of embryos of rank A were significantly higher (p < 0.05) than those of rank B, irrespective of the day of blastocyst appearance after IVF. Neither did the proportion of male embryos of ranks A and B differ significantly from each other at any of the days examined, nor from the average proportion (53%). The oxygen consumption rate of embryos of rank B collected on day 8 was significantly higher (p < 0.05) in female embryos than in male embryos collected on the same day. However, there were no apparent differences of oxygen consumption rates at each day of blastocyst appearance between male and female embryos of rank A. These results indicate that the oxygen consumption rate of individual embryos reflects their quality but does not correlate with the sex ratio of embryos of excellent quality.     

PCR方法鉴定牛早期胚胎性别研究进展

对用于早期胚胎性别鉴定的多重PCR、巢式PCR、引物一扩展预扩增PCR、非电泳PCR和LAMP法等扩增技术进行了综述,并针对早期胚胎性别鉴定技术在养牛业生产中的应用现状和存在问题进行分析与讨论,展望了PCR性别鉴定技术在养牛业中广阔的商业应用前景。     

牛早期胚胎性别鉴定PCR反应体系优化的研究

根据牛SRY基因序列设计合成2对巢式PCR引物作为性别鉴定引物,根据牛-珠蛋白基因序列设计了一对引物作为内标引物建立了牛胚胎性别鉴定的PCR反应体系。公牛可以扩增出187bp的SRY基因片段和255 bp的-珠蛋白基因片段,母牛只能扩增出255 bp的-珠蛋白基因片段。由于巢式PCR只需3～8个细胞就可以在紫外灯下看到扩增结果,而常规PCR则需要较多的细胞,所以胚胎性别鉴定时使用巢式PCR效果更好。