Nogueira Marcelo F Gouveia, Melo Danilas S, Carvalho Luciano M, Fuck Egon J, Trinca Luzia A, Barros Ciro Moraes
Department of Pharmacology, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brazil.
Theriogenology. 2004 May;61(7-8):1283-90. doi: 10.1016/j.theriogenology.2003.07.012.
The objective of this study was to evaluate the effects of equine chorionic gonadotropin (eCG) treatment on the number of induced accessory corpora lutea (CL), plasma progesterone concentrations and pregnancy rate in cross-bred heifers after transfer of frozen-thawed (1.5M ethylene glycol) embryos. All recipients received 500 microg PGF2alpha (dl-cloprostenol, i.m.) at random stages of the estrous cycle (Day 0) and were observed for estrus for 7 days. On Day 14, heifers detected in estrus between 2 and 7 days after PGF2alpha treatment were randomly allocated to four groups ( n=83 per group) and given 0 (control), 200, 400, or 600 IU of eCG. Two days later (Day 16), these recipients were given PGF2alpha and observed for estrus. Six to eight days after detection of estrus, plasma samples were collected to determine progesterone concentration and ultrasonography was performed to observe ovarian structures. Heifers with multiple CL or a single CL >15 mm in diameter received an embryo by direct transfer. Embryos of excellent and good quality were thawed and transferred to the recipients by the same veterinarian. Pregnancy was diagnosed by ultrasonography and confirmed by transrectal palpation 21 and 83 days after embryo transfer (ET), respectively. Plasma progesterone concentrations on the day of transfer (Day 7 of the estrous cycle) were 3.9+/-0.7, 4.2+/-0.4,6.0+/-0.4 and 7.8+/-0.6 ng/ml for groups Control, 200, 400, and 600, respectively (Control versus treated groups P=0.009; 200 versus 400 and 600 groups P=0.0001; and 400 versus 600 P=0.012 ). Conception rates 83 days after ET were 41.9, 50.0, 25.0, and 20.9% for groups Control, 200, 400, and 600, respectively (200 versus 400 and 600 groups P=0.0036 ). In conclusion, an increase in progesterone concentration, induced by eCG treatment, did not improve pregnancy rates in ET recipients. Conversely, there was a decline in conception rates in the animals with the highest plasma progesterone concentrations.
本研究的目的是评估马绒毛膜促性腺激素（eCG）处理对冻融（1.5M乙二醇）胚胎移植后的杂交小母牛诱导副黄体（CL）数量、血浆孕酮浓度和妊娠率的影响。所有受体在发情周期的随机阶段（第0天）接受500微克PGF2α（氯前列醇，肌肉注射），并观察7天的发情情况。在第14天，在PGF2α处理后2至7天检测到发情的小母牛被随机分为四组（每组n = 83），并分别给予0（对照组）、200、400或600国际单位的eCG。两天后（第16天），这些受体接受PGF2α并观察发情情况。在检测到发情后6至8天，采集血浆样本以测定孕酮浓度，并进行超声检查以观察卵巢结构。有多个CL或单个CL直径>15毫米的小母牛通过直接移植接受胚胎。优质和良好质量的胚胎由同一位兽医解冻并移植到受体中。分别在胚胎移植（ET）后21天和83天通过超声检查诊断妊娠，并通过直肠触诊确认。移植当天（发情周期第7天）对照组、200、400和600组的血浆孕酮浓度分别为3.9±0.7、4.2±0.4、6.0±0.4和7.8±0.6纳克/毫升（对照组与处理组P = 0.009；200组与400和600组P = 0.0001；400组与600组P = 0.012）。ET后83天的受孕率对照组、200、400和600组分别为41.9%、50.0%、25.0%和20.9%（200组与400和600组P = 0.0036）。总之，eCG处理诱导的孕酮浓度升高并未提高ET受体的妊娠率。相反，血浆孕酮浓度最高的动物受孕率下降。
