Swine and Poultry Research Center, Shizuoka Prefectural Research Institute of Animal Industry, Kikugawa, Shizuoka, 439-0037, Japan.
J Anim Sci. 2012 Dec;90(13):4781-7. doi: 10.2527/jas.2012-5178. Epub 2012 Jul 24.
In the present study, we investigated the influence of exogenous estrogen on embryo survival after transfer into prepubertal gilts in which estrus had been induced. In the first experiment, estrus was induced in prepubertal gilts by the administration of 1,000 IU of eCG and 750 IU of hCG every 72 h. Several blastocysts were recovered on d 6 (d 0 is the day of hCG administration), and 1 embryo was transferred to the tip of 1 side of the uterine horn on d 6 (Control). In treated groups, after embryo transfer, 5 mg of estradiol benzoate (EB) was administered on d 11 (EB5mg-1) or d 11, d 13, and d 15 (EB5mg-3) or d 11, 12, 13, 14, and 15 (EB5mg-5) or 20 mg of estradiol dipropionate (EDP) was administered on d 11 (EDP20mg-1) or d 11 and d 14 (EDP20mg-2). Autopsy examinations were performed on d 53 to 60. Although nontreated gilts did not become pregnant, gilts in each of the estradiol-treated groups became pregnant. The greatest pregnancy rate (77.8%, 7/9) was obtained with EDP20mg-2 (EDP20mg-2 > control: P < 0.05). In a second experiment, 1 blastocyst was transferred to prepubertal gilts and treated with EDP20mg-2. Pregnancy in recipient pigs was confirmed by ultrasonography, and pigs were allowed to farrow. Embryo survival rate was high on d 30 of pregnancy (75%, 9/12) but had a tendency (P = 0.0995) to decline from d 30 to delivery (33.3%, 4/12). In a third experiment, prepubertal gilts were administered 5 mg of EDP on d 11 (EDB5mg-1) and d 11 and d 14 (EDP5mg-2). Autopsy examinations were performed on d 53 to 58. Pseudopregnancy rate was high for EDP5mg-2 (63.6%, 7/11) compared with EDP5mg-1 (0%, 0/11; P < 0.05). In a fourth experiment, prepubertal gilts were transferred 1 blastocyst and treated with EDP5mg-2. Pregnancy was confirmed in recipient pigs by ultrasonography, and pigs were subsequently allowed to farrow. Embryo survival rate remained unchanged from d 30 of pregnancy to delivery (66.7%; 8/12). One piglet died from dystocia, and 1 suffered from deformity involving double-breasted hooves and died 6 d after birth. There was no difference (P > 0.05) in survival rate on d 30 of pregnancy and weaning (50%, 6/12). Body weight at birth and at weaning did not differ from that reported in previous studies. In conclusion, this study showed that EDP5mg-2 treatment during early pregnancy leads to full-term development of a single embryo.
在本研究中，我们研究了外源雌激素对诱发发情的未成年小母猪胚胎移植后存活的影响。在第一个实验中，通过每隔 72 小时给予 1000IU 的 eCG 和 750IU 的 hCG 来诱导未成年小母猪发情。在第 6 天（hCG 给药日为 d0）回收了几个囊胚，并在第 6 天（对照组）将 1 个胚胎移植到子宫角的尖端。在处理组中，胚胎移植后，于第 11 天（EB5mg-1）或第 11、13 和 15 天（EB5mg-3）或第 11、12、13、14 和 15 天（EB5mg-5）给予 5mg 苯甲酸雌二醇（EB）或于第 11 天（EDP20mg-1）或第 11 和 14 天（EDP20mg-2）给予 20mg 雌二醇二丙酸酯（EDP）。于第 53 至 60 天进行剖检检查。虽然未处理的小母猪未怀孕，但在每个雌二醇处理组中的小母猪均怀孕。怀孕率最高（77.8%，7/9）的是 EDP20mg-2（EDP20mg-2>对照：P<0.05）。在第二个实验中，将 1 个囊胚移植到未成年小母猪，并使用 EDP20mg-2 处理。通过超声检查确认受体猪怀孕，并允许其分娩。在妊娠第 30 天，胚胎存活率很高（75%，9/12），但从第 30 天到分娩时（33.3%，4/12）有下降趋势（P=0.0995）。在第三个实验中，于第 11 天（EDB5mg-1）和第 11 天和第 14 天（EDP5mg-2）给予未成年小母猪 5mg 的 EDP。于第 53 至 58 天进行剖检检查。与 EDP5mg-1（0%，0/11）相比，EDP5mg-2 的假性怀孕率较高（63.6%，7/11；P<0.05）。在第四个实验中，将 1 个囊胚移植到未成年小母猪，并使用 EDP5mg-2 处理。通过超声检查确认受体猪怀孕，并允许其分娩。在妊娠第 30 天至分娩时，胚胎存活率保持不变（66.7%，8/12）。1 头仔猪因难产死亡，1 头仔猪因双蹄畸形而死亡，出生后 6 天死亡。妊娠第 30 天和断奶时的存活率没有差异（P>0.05）。出生体重和断奶体重与之前的研究报告没有差异。总之，本研究表明，EDP5mg-2 在妊娠早期的处理可导致单个胚胎足月发育。
