肝素或钙离子载体诱导牛、羊冻精体外获能的研究

本文采用肝素或钙离子载体(I-A)诱导牛、羊冻精体外获能,根据对去透明带仓鼠卵的穿透情况评定获能效果,并用台盼蓝·姬姆萨(TG)染色观察了精子的死活及顶体状态.结果发现,牛、羊冻精经肝素或I-A处理后与卵子一起培养,2 h穿透仓鼠卵,4 h开始形成雄原核,6 h形成发育良好的雄原核.牛冻精用50μg/mL肝素及0.1μmol/L I-A处理效果最好,穿透率分别为72.8％和92.3％;羊则以20μg/mL肝素及0.3μmol/L I-A为宜,穿透率分别为73.1％和68.O％.咖啡因与I-A或肝素并用均有协同作用,能提高精子的穿透能力,并能促进卵内原核的发育.肝素和I-A均能在体外诱导牛、羊冻精的顶体反应,有顶体反应活精子百分率与穿透率呈强正相关,羊冻精比较脆弱,获能处理后活力较低.     

钙离子载体诱导猪冷冻精子体外获能的研究

本研究首次报道了猪冷冻精子的体外获能。用 I—A 诱导猪冷冻精子体外获能,可穿透去透明带仓鼠卵。I—A 浓度以0.3μM 为宜,穿透率为60%,有原核卵百分率为39.2%。咖啡因可促进 I—A 的作用,并能促进卵内原核的发育。I—A 可诱导猪冷冻精子的顶体反应,有顶体反应活精子百分率与穿透率呈强正相关(r=0.968,P<0.01,n=12)。结果说明,用 I—A 诱导获能的猪冻精可用于猪的卵子的体外受精。猪冻精在卵内的发育能力较低,推测这是猪冷冻精子受胎率低的一个主要原因。     

诱导牛精子体外获能方法的研究

用去透明带的金黄地鼠卵异种精子体外穿透试验,检测冻精复苏,经各种处理后的精子穿卵率,结果表明,B0培养基,经咖啡因2mmol/L,肝素50μg/ml处理,并添加亚牛磺酸70μmol/L和透明质酸酶1g/L,是诱导牛精子体外获能的有效方法。     

黑白花公牛冻精受精力的检测—穿透仓鼠卵的试验

本试验用SPA法(Sperm Penetration Assay)即精子穿透分析法对8头黑白花公牛冻精的受精力进行检测,以预测各公牛精液受精力的水平。结果:每卵表面平均精子数为3.2～9.5个,每卵内精子数为1.6～3.4个,被穿透的卵子比例即穿透率为34.9～65.7％,具雄原核的卵子比例即原核卵率为16.0～32.4％。这些数值与各公牛冻精授精500多头母牛的效果作对照,8头公牛平均80(70～90)天的不返情率为56％(45.8～71.1％),不返情率与雄原核卵率,穿透率呈高度正相关,相关系数分别为 0.82和 0.92。 另一组试验结果表明:授精时间对穿透率特别是对雄原核形成有很大影响。授精2小时后观察,没有雄原核形成,只有附着于卵子表面的精子;授精4小时后,精子已通过卵黄膜进入卵内,并开始形成雄原核;授精6小时后形成发育良好的雄原核。 这些观察结果有助于利用这项技术在生产上对公牛精液的受精力进行客观评定,为选择后备公牛提供重要的生理指标,特别是对评定冷冻精液的品质具有一定的参考价值。并为精子顶体反应、受精机理、体外受精、遗传学和胚胎学等领域的研究提供新的手段。     

肝素和钙离子载体诱导猪射出精子体外获能的研究

本文采用肝素和钙离子载体诱导猪射出精子体外获能,根据对去透明带仓鼠卵的穿透情况评价获能效果,并用台盼兰·姬姆萨染色观察精子的死活及顶体状态。结果表明,未经获能处理的猪精子不能穿透仓鼠卵,肝素和I-A均能诱导猪精子体外获能并引起顶体反应。经获能处理的精子,在授精后2小时穿透卵子,4小时开始形成雄原核,6小时形成发育良好的雄原核。肝素处理以100μg效果最好,穿透率达77.8%,有原核卵百分率达47.2%;I-A处理以0.3uM为宜,穿透率达66.7%,有原核卵百分率达42.4%。咖啡因与肝素和I-A具有协同作用,能提高精子的穿透能力。有顶体反应的活精子百分率与穿透率呈强正相关(肝素组:r=0.97,P<0.01;I-A组:r=0.94,P<0.01)。     

牛精子染色体制备及影响因素探讨

用去透明带金黄地鼠卵异种体外受精技术制备了牛精子单倍染色体。冻精复苏、洗涤、获能用 Ｈａｍ  Ｆ１０ 和 Ｒ Ｐ Ｍ Ｉ１６４０ 为主的混合培养基，辅以亚牛磺酸、肾上腺素，１０ μｍ ｏｌ／ Ｌ 钙离子载体（ Ｉ Ａ）处理牛精子 １２～１５ ｍ ｉｎ，诱导获能。异合卵用 Ｔ Ｃ１９９ 培养，以鬼臼毒素和长春花碱阻断原核融合和纺锤体形成，其浓度为常规浓度的 ２ 倍，在第 １ 次卵裂中期制备染色体。结果显示穿卵率达 ８３８％ ，可分析精子染色体核型成功率为 ４２４％ 。认为这是一种有效制备牛精子染色体的方法，并对其影响因素进行了探讨。     

肝素和钙离子载体诱导波尔山羊精子体外获能和体外受精

运用肝素、钙离子载体（IA）协同咖啡因诱导波尔山羊精子体外获能，利用去透明带金黄地鼠卵穿透试验检测了精子的获能效果。结果发现：精卵孵育4h和6h时的穿透率均高于2h时的穿透率；肝素和钙离子载体对精子获能有明显的促进作用，与未添加组相比差异极显著（P〈0．01）；20mg／L和50mg／L的肝素剂量组，去透明带金黄地鼠卵穿透率为64．7％、68．4％；钙离子载体的添加剂量在0．3μmol／L时，穿透率达到68．2％；咖啡因与肝素、钙离子载体具有明显的协同作用。将获能的精子与山羊卵母细胞进行体外受精孵育17h，也获得了60％以上的受精率。     

不同浓度抗生素的稀释液对牛冷冻精液质量的影响

本试验用添加了不同浓度抗生素的稀释液对5头种公牛精液进行稀释、封装和冷冻,检查牛冻精解冻后的精子活力、畸形率和细菌数。结果表明,抗生素添加范围在1 000～2 000IU/mL内,冻精活力≥35%,细菌数控制在30个左右,冻精质量符合国家标准。     

肝素和钙离子载体诱导马 驴冻精体外获能的研究

80年代以来,牛、羊、猪的体外受精先后取得了成功,但马、驴体外受精的研究却一直无人问津,迄今未见成功的报道。为此,我们进行了肝素和钙离子载体(Ionopho-re A23187,I-A)诱导马、驴冻精体外获能的研究,并探讨咖啡因与二者的协同作用。用去透明带仓鼠卵检测获能效果,用台盼蓝·姬姆萨(TG)染色观察精子的死活及顶体形态。     

猪精子体外获能方法研究——咖啡因使用方法

猪卵子体外受精率低的原因之一是猪精子体外获能比较困难。本试验利用猪精子对去透明带仓鼠(Hamster)卵子的穿透实验,探讨了用苯甲酸钠咖啡因促进猪精子体外获能的方法。     

The effect of porcine follicular fluid on the interaction of boar spermatozoa with zona-free hamster ova.

Boar spermatozoa were cocultured with zona-free hamster ova (eggs) to assess the effects of preovulatory porcine follicular fluid (pFF) in the capacitation medium or gamete coculture (fertilization) medium (pFF; 0, 10 or 40% v/v) on subsequent sperm-egg interaction. Increasing pFF concentrations in the capacitation medium resulted in a progressive decrease in the average numbers of sperm attaching to or penetrating each ovum. When pFF was included in the fertilization medium, but not in the capacitation medium, the average numbers of sperm attaching to or penetrating each ovum and the percentage of ova with sperm attached decreased markedly with increasing pFF concentrations. The percentage of ova with greater than five sperm attached decreased from 84% to 13% and 0% with 0%, 10% and 40% pFF, respectively. Sperm attachment was completely inhibited in approximately 50% of the ova cocultured in 40% pFF. The percentage of ova penetrated by greater than five sperm decreased from 82% to 21% and 7% with 0%, 10% and 40% pFF, respectively. Preincubation of ova in 40% pFF prior to coculture with sperm also resulted in a reduction in sperm attachment and penetration. These results suggest that pFF contains substance(s) that alter the ability of boar spermatozoa to interact with the hamster ovum plasma membrane in vitro.     

Estimation of the quality of irradiated spermatozoa from cockerels using the classical method and zona-free hamster ova

1. The quality of gamma irradiated spermatozoa from cockerels was investigated by measuring motility, oxygen consumption and ability to penetrate zona-free hamster ova. 2. Doses of 750 Gy slightly reduced motility and oxygen consumption; however, irradiated spermatozoa penetrated on average 56% (minimum 33%) of hamster ova. 3. The zona-free hamster ova test may be useful for estimating avian sperm quality.     

Sperm penetration assay as an indicator of bull fertility

To predict the fertility of frozen-thawed bull spermatozoa, a sperm penetration assay (SPA) using zona-free hamster oocytes was optimized, and the assay results were compared with data from field fertility expressed as the non-return rate (NRR). To increase sperm penetration, the spermatozoa were pre-incubated and coincubated with oocytes in media containing various concentrations of heparin (0 to 50 μg/ml). Coincubation with 10 μg/ml heparin showed the highest sperm penetration (P<0.05); it is considered to be the optimized SPA method. Sperm fertility index values obtained from WSPA were significantly correlated with the historic average NRR of 46 bulls (P<0.01). To determine the normal range for SPA, we established the lower limits of the sperm fertility index and set the cut-off value at 2.55, at which point the NRR was more than 70%, using the receiver operating characteristic curve. The overall accuracy for the 46 bulls was 95.7% (44/46) for both the low and high NRR, with a sensitivity of 95.5% (21/22) and a specificity of 95.8%. This protocol would make it easier to discriminate bulls according to their sperm fertilizing ability.     

Relationship between the sperm count and the fertilization rate of ova ovulated from the contralateral ovary in intrauterine horn insemination in cats

Unilateral intrauterine horn insemination (UIUI) was carried out in cats, and we investigated the fertilization rate of ova ovulated from the contralateral ovary. Various numbers of sperm were used to inseminate the uterine horn on the side where ovulation was inhibited. The rates of conception were 1/11 (9.1%), 2/11 (18.2%), and 5/7 (71.4%) in the 2 x 10(6), 4 x 10(6), and 8 x 10 (6) groups, respectively. Furthermore, the fertilization rate was 70.7% in the 8 x 10(6) group. Thus, ova ovulated from the contralateral ovary were not fertilized or the fertilization rate was low in some cats even when UIUI was performed with a large number of sperm.     

蛋黄中低密度脂蛋白对冻融后猪精子DNA完整性及受精率的影响

本实验目的是评价低密度脂蛋白(LDL)对冻融后猪精子DNA完整性及受精率的影响。结果表明:添加9%LDL处理组冷冻解冻后,精细胞DNA完整率(彗星长为13.21,尾长为10.28,尾部DNA(%)为16.54,尾矩为2.31)和卵裂率(43.12%)都与7%、8%和10%LDL处理组差异显著(P<0.05)。本实验表明LDL能显著提高冷冻解冻后猪精子DNA的完整性;也能显著改善冷冻解冻后猪精子体外受精(IVF)率。     

肉碱对冻融猪精子总抗氧化能力、抗氧化酶基因及凋亡相关基因表达的影响

试验旨在探究肉碱对冻融猪精子质量、抗氧化、抗凋亡及精卵结合能力的影响。试验分鲜精组和冻融组,冻融组的肉碱浓度分别为0、0.025、0.05、0.075 mg/mL,对冻融后的精子质量、总抗氧化能力、抗氧化酶相关基因及凋亡相关基因mRNA表达、精卵结合能力进行检测。结果显示,在冻融组中,经过肉碱处理的精子存活率、质膜完整率和顶体膜完整率均显著高于0 mg/mL处理组（P < 0.05）,其中肉碱浓度为0.05 mg/mL时改善效果最好;经过冻融处理的精子中丙二醛（MDA）浓度与鲜精组相比显著升高（P < 0.05）,其中肉碱浓度为0.05 mg/mL时显著低于其他肉碱处理组（P < 0.05）;与鲜精组相比,各冻融组精子总抗氧化能力均显著降低（P < 0.05）,肉碱浓度为0.05 mg/mL时总抗氧化能力最高。此外,与鲜精组相比,0 mg/mL肉碱处理组中凋亡相关基因Caspase-3与Bax的相对表达量显著升高（P < 0.05）,抗凋亡基因Bcl-2的相对表达量显著降低（P < 0.05）,抗氧化酶相关基因SOD2、CAT与GPx的相对表达量显著降低（P < 0.05）;冻融组精卵结合能力均下降,但肉碱浓度为0.05 mg/mL时可得到显著改善（P < 0.05）。结果表明,添加肉碱可以改善冻融猪精子的质量、抗氧化能力、抗凋亡能力及精卵结合能力。     

Effect of capacitation of stallion sperm with polyvinylalcohol or bovine serum albumin on penetration of bovine zona-free or partially zona-removed equine oocytes

Experiments were conducted to study effects of macromolecules on stallion sperm capacitation and fertilization as determined by penetration of bovine zona-free and equine partially zona-removed oocytes. Stallion sperm were capacitated in TYH medium (modified Krebs-Ringer bicarbonate) supplemented with either 1 mg/mL of polyvinylalcohol (PVA) or 4 mg/mL of BSA. Capacitation was induced with 8 bromoadenosine cyclic monophosphate (8BrcAMP; 0.5 mM) alone or in combination with 0.1 microM of ionomycin. Intraspecies gametes were co-incubated in TYH/PVA or TYH/BSA for 18 to 20 h. For zona-free bovine oocytes, penetration rate (35%) with the combination of 8BrcAMP and ionomycin in PVA-containing medium was higher (P < 0.05) than any treatment in BSA-containing medium (5 to 6%). A similar study was conducted using equine oocytes with partially removed zonae. Sperm capacitated and used for in vitro fertilization (IVF) in PVA-containing medium had higher penetration rates (P < 0.01) than sperm in BSA-containing medium (54 vs. 11%). The effect of equine preovulatory follicular fluid on bovine oocyte penetration was assessed. Bovine oocytes were matured in tissue culture medium-199 with 0, 20, 50, or 100% equine preovulatory follicular fluid, and 1 IU/mL of equine chorionic gonadotropin. Stallion sperm were treated with 8BrcAMP + ionomycin in PVA- or BSA-containing media. The penetration rates of bovine zona-free oocytes by stallion sperm were again higher with PVA (47%) than BSA (18%; P < 0.01). Penetration rates of oocytes matured in 100% follicular fluid were higher (P < 0.05) than for oocytes matured with 0% follicular fluid. The effects of equine follicular fluid and PVA/BSA during sperm capacitation on standard bovine IVF were examined. Culture of bovine oocytes with equine follicular fluid did not affect oocyte maturation or penetration rates after IVF. Bovine sperm capacitated with heparin in PVA-containing medium yielded lower (P < 0.05) fertilization rates than those capacitated in BSA-containing medium when incubated with both zona-intact and zona-free bovine oocytes. In summary, PVA was superior to BSA for ionophore-induced capacitation of equine sperm for penetration of zona-free bovine oocytes or partially zona-removed equine oocytes, but not for standard bovine IVF with bovine sperm. Zona-free bovine oocytes may be useful for assaying in vitro capacitation and fertilization of stallion sperm.     

In vitro production of sexed embryos for gender preselection: high-speed sorting of X-chromosome-bearing sperm to produce pigs after embryo transfer

The objectives for the present experiments were to apply sperm sexing technology to an in vitro production system with porcine oocytes obtained from slaughterhouse material. On six experimental days, ovaries were obtained from an abattoir, and cumulus-oocyte-complexes were matured in vitro. Semen was collected from mature boars of proven fertility and was sorted for X-chromosome-bearing sperm, using the Beltsville Sperm Sexing Technology incorporating the use of high-speed sorting. A total of 5,378 oocytes were submitted for in vitro fertilization (IVF). Of these, 559 ova were stained for cytogenetic analysis 18 h after IVF. From the remaining 4,819 ova, 1,595 cleaved, and 1,300 of the cleaved embryos were transferred into 26 synchronized recipients (5 control gilts for unsorted sperm, 21 gilts for X-sorted sperm). In a test of two fertilization media (FERT-A vs FERT-B) higher cleavage rates (P<.05) were obtained when FERT-B was used as a fertilization medium for unsorted (43.4+/-5.1%) and sorted sperm (43.1+/-1.1%;), whereas in FERT-A unsorted sperm gave a cleavage rate of 17.9+/-4.4% and sorted sperm gave 30.4+/-1.4%. Additionally, cleavage rates were higher (P<.05) after fertilization with sorted sperm vs unsorted sperm, independent of fertilization medium. Cytogenetic analysis of ova revealed that more oocytes with unsorted than with sorted sperm remained in Metaphase 2 arrest (P<.05). This was also independent of the fertilization medium. Monospermic fertilization rates were the same for IVF with unsorted or sorted sperm, independent of the fertilization system, except FERT-A with unsorted sperm (P<.05). Polyspermic fertilization rates were highest in FERT-B (37.6+/-6.6). A total of 57 pigs were born from nine litters. Six litters from sexed sperm (X-sorted) produced 33 females (97%) and one male. Three litters from control transfers produced 23 pigs, 11 of which were female (48%). The sex ratio of the offspring was predicted based on the sort reanalysis of the sorted sperm for DNA content.     

Fertility after different artificial insemination methods using a synthetic semen extender in sheep

The present study aimed to investigate the fertility of ewes artificially inseminated with three different methods using a synthetic semen extender, AndroMed. The three methods of artificial insemination (AI) were cervical AI with fresh-diluted or frozen-diluted semen at observed estrus, and an intrauterine AI with frozen-thawed semen. A total of 80 ewes were treated with a controlled internal drug release (CIDR) containing 0.3 g progesterone per device for 12 days. In Experiment 1 (26 Suffolk ewes), superovulation was induced with 20 mg follicle-stimulating hormone and 250 IU equine chorionic gonadotropin (eCG) two days and one day before CIDR removal, respectively, during the non-breeding season. In Experiment 2 (54 Suffolk and Suffolk crossbred ewes), an intramuscular injection of 500 IU eCG was administered one day before CIDR removal to synchronize estrus and ovulation during the breeding season. In Experiment 1, fresh-diluted or frozen-thawed semen was deposited into the cervical orifice after estrus detection, and an intrauterine AI with frozen-thawed semen was performed by laparoscopy at a fixed-time basis without estrus detection. Embryos were recovered by uterine flushing 6 days after AI, and the rates of recovered, fertilized (cleaved) ova and embryos at the morula or blastocyst stage were compared among the three AI methods. In Experiment 2, the pregnancy rates after the three AI methods were compared. In Experiment 1, the rates of recovered ova were not significantly different among the three AI methods (52.5-56.7%). The rate of fertilized ova (81.0%) by laparoscopic AI with frozen-thawed semen was significantly higher compared with cervical AI of fresh-diluted (25.5%) or frozen-thawed (3.5%) semen, but the rate of embryos at the morula or blastocyst stage (17.6%) was significantly lower than that of the cervical AI with fresh-diluted semen (69.2%). The rates of ewes yielding fertilized ova were not significantly different among the three groups (44.4, 11.1 and 62.5% for cervical AI with fresh-diluted and frozen-thawed semen and intrauterine AI with frozen-thawed semen). In Experiment 2, the pregnancy rate of ewes intrauterinally inseminated with frozen-thawed semen (72.2%) was significantly higher than those of ewes inseminated cervically with fresh-diluted (5.5%) or frozen-thawed (0.0%) semen. The present results showed that acceptable fertilization and pregnancy rates could be obtained by an intrauterine AI with frozen-thawed semen using a synthetic semen extender (AndroMed), but not sufficient by the cervical AI with either fresh or frozen semen.     

Effect of unilateral cornual insemination upon fertilization rate in superovulating and single-ovulating cattle

In Exp. 1, 21 first-service cattle and seven repeat-breeder cattle, averaging 4.7 infertile services, were brought into estrus and superovulated by treatment with follicle-stimulating hormone and prostaglandin F2 alpha. At insemination, semen was deposited in the greater curvature of one uterine horn, about midway between the utero-cervical junction and the utero-tubal junction. Cattle were necropsied 2 to 7 d after estrus and ova were recovered and examined. The fertilization rate for first-service cows was 74% of 362 intact ova and for repeat-breeders, 43% of 128 intact ova (P less than .001). Fertilization rate in first-service cows was 81% on the side of semen deposition and 68% on the opposite side (P less than .01); the rates in repeat-breeders were 54% and 32% (P less than .025). Differences between sides were due mostly to four cows that averaged 93% fertilization on the side of semen deposition and 19% on the opposite side. The proportion of fertilized ova with accessory sperm (17%) did not differ between sides of the reproductive tract. In Exp. 2, 60 first-service and 32 repeat-breeder cows in natural estrus had semen deposited in the uterine body or in the greater curvature of one uterine horn, either on the side of impending ovulation or on the opposite side. At necropsy, 55 ova were recovered from first-service cows, of which 42 (76%) were intact and 13 (24%) were ruptured or fragmented. Of the 42 intact ova, 41 (98%) were cleaved. From the 32 repeat-breeders, 30 ova were recovered, of which 26 (87%) were intact and 4 (13%) were ruptured; 23 of the 26 intact ova (88%) were cleaved. Site of semen deposition had no significant effect on either fertilization rate or number of accessory sperm in either type of cow. First-service cows averaged more accessory sperm (40) than did repeat-breeders (19, P less than .01). Overall results indicated that sperm deposited deep in one uterine horn fertilized ova nearly as frequently in the opposite oviduct as in the adjacent oviduct except in 14% of superovulating cattle.