Galvão K N, Santos J E P, Coscioni A C, Juchem S O, Chebel R C, Sischo W M, Villaseñor M
Veterinary Medicine Teaching and Research Center, University of California-Davis, Tulare 93274, USA.
J Dairy Sci. 2006 Jun;89(6):2056-64. doi: 10.3168/jds.S0022-0302(06)72273-1.
Objectives were to determine the effects of gossypol exposure during early embryo development on embryonic survival after transfer of frozen and thawed embryos to lactating dairy cows treated with human chorionic gonadotropin (hCG). Holstein cows (n = 269) were either treated or not treated with 3,300 IU of hCG on d 5 of the estrous cycle and received an embryo collected from heifers fed or not fed gossypol. Embryo donor heifers consumed either 0 or 12 g/d of free gossypol for 76 d prior to embryo collection, resulting in mean plasma gossypol concentrations of 0 and 7.38 microg/mL, respectively. Embryos were transferred on d 7 of the estrous cycle and pregnancy diagnosed 21 and 35 d later. Progesterone was analyzed in plasma collected on d 5 and 12 of the estrous cycle. Treatment with hCG increased the total luteal area on d 12 (818.0 vs. 461.1 mm2) because of increased number of corpora lutea (2.0 vs. 1.0) and increased area of the original corpora lutea (522.7 vs. 443.5 mm2). Plasma progesterone concentrations were similar between treatments on d 5, but increased by d 12 in hCG-treated cows (6.46 vs. 4.78 ng/ mL). Pregnancy rates on d 28 and 42 were not affected by hCG. However, after transfer into lactating cows, embryos collected from heifers not fed gossypol resulted in higher pregnancy rates at 28 d (33.3 vs. 23.1%) and 42 d (29.6 vs. 20.2%) of gestation compared with embryos collected from heifers fed gossypol. Our data suggest that the negative effects of gossypol on fertility are mediated by changes in embryo viability in spite of similar grade quality at transfer.
目的是确定在胚胎发育早期接触棉酚对冷冻解冻胚胎移植到用人绒毛膜促性腺激素（hCG）处理的泌乳奶牛后胚胎存活的影响。在发情周期的第5天，对269头荷斯坦奶牛进行3300国际单位hCG处理或不处理，并移植从饲喂或未饲喂棉酚的小母牛收集的胚胎。胚胎供体小母牛在胚胎收集前76天每天分别消耗0或12克游离棉酚，导致平均血浆棉酚浓度分别为0和7.38微克/毫升。在发情周期的第7天进行胚胎移植，并在21天和35天后诊断妊娠。在发情周期的第5天和第12天收集的血浆中分析孕酮。hCG处理增加了第12天的黄体总面积（818.0对461.1平方毫米），这是由于黄体数量增加（2.0对1.0）和原始黄体面积增加（522.7对443.5平方毫米）。第5天各处理间血浆孕酮浓度相似，但hCG处理的奶牛到第12天孕酮浓度升高（6.46对4.78纳克/毫升）。第28天和第42天的妊娠率不受hCG影响。然而，与从饲喂棉酚的小母牛收集的胚胎相比，移植到泌乳奶牛后，从未饲喂棉酚的小母牛收集的胚胎在妊娠28天（33.3%对23.1%）和42天（29.6%对20.2%）时妊娠率更高。我们的数据表明，尽管移植时胚胎等级质量相似，但棉酚对生育能力的负面影响是由胚胎活力的变化介导的。
