Department of Animal Science and Center for Animal Biotechnology and Genomics, Texas A&M University, College Station, TX 77843-2471, USA.
J Anim Sci. 2012 Jan;90(1):159-70. doi: 10.2527/jas.2011-4180. Epub 2011 Aug 12.
This study was designed to characterize development of the ovine conceptus throughout gestation to establish the temporal relationships in metabolites, electrolytes, fluid volumes within the placenta, and hormonal changes with fetal growth. Length and weight of placentae, weight of cotyledons, and uterine weight increased between d 25 and 80 of gestation in advance of increases in fetal growth between d 80 and 140 of gestation. Allantoic fluid volumes changed (P < 0.01) between d 25 (21 mL) and 40 (91 mL), decreased to d 70 (32 mL), and then increased to d 140 (438 mL). Concentrations and total amounts of proteins in allantoic fluid were reduced between d 25 and 50, but total protein increased (P < 0.01) from d 40 (63 mg) to d 140 (2,991 mg). Concentrations of fructose in allantoic fluid varied between 2 and 6 mg/mL throughout gestation, but total fructose increased (P < 0.01) between d 25 (46 mg) and d 120 (679 mg). Concentrations of glucose ranged from 0.1 to 0.3 mg/mL, and total glucose increased (P < 0.05) from d 25 (3 mg) to d 140 (63 mg) of gestation. Amniotic fluid volume increased (P < 0.01) between d 30 and 140. Concentrations of estrogens in allantoic fluid, maternal uterine artery, and uterine vein increased (P < 0.01) with advancing pregnancy, and concentrations of progesterone in allantoic fluid (P < 0.07) and plasma (P < 0.05) were affected by day of gestation. Concentrations of glucose were greater (P < 0.05) in uterine artery than uterine vein, but concentrations of electrolytes and osmolarity of plasma were not affected by day of gestation. Increases in weights of fetal organs were proportional to increases in fetal weight during gestation. Results of the present study of conceptus growth and development highlight areas of needed research and provide benchmarks for comparisons when evaluating effects of various treatments, environmental conditions, and epigenetics on successful outcomes of pregnancy in sheep.
本研究旨在描述绵羊胚胎在整个妊娠期的发育情况，以确定代谢物、电解质、胎盘内液体量和激素变化与胎儿生长之间的时间关系。在妊娠第 80 天至 140 天胎儿生长之前，胎盘的长度和重量、胎叶的重量和子宫的重量增加。羊膜液体积在妊娠第 25 天（21 毫升）和第 40 天（91 毫升）之间发生变化（P < 0.01），减少到妊娠第 70 天（32 毫升），然后增加到妊娠第 140 天（438 毫升）。羊膜液中蛋白质的浓度和总量在妊娠第 25 天至 50 天之间减少，但从妊娠第 40 天（63 毫克）到第 140 天（2991 毫克），总蛋白增加（P < 0.01）。整个妊娠期羊膜液中果糖的浓度在 2 至 6 毫克/毫升之间变化，但总果糖增加（P < 0.01），从妊娠第 25 天（46 毫克）到第 120 天（679 毫克）。葡萄糖浓度在 0.1 至 0.3 毫克/毫升之间，总葡萄糖从妊娠第 25 天（3 毫克）增加到妊娠第 140 天（63 毫克）（P < 0.05）。羊水量在妊娠第 30 天至第 140 天之间增加（P < 0.01）。羊膜液、母体子宫动脉和子宫静脉中的雌激素浓度随着妊娠的进展而增加（P < 0.01），而羊膜液（P < 0.07）和血浆（P < 0.05）中的孕酮浓度则受到妊娠天数的影响。子宫动脉中的葡萄糖浓度高于子宫静脉（P < 0.05），但电解质和血浆渗透压浓度不受妊娠天数的影响。胎儿器官重量的增加与胎儿体重的增加成正比。本研究对胚胎生长和发育的结果强调了需要研究的领域，并为评估各种治疗方法、环境条件和表观遗传学对绵羊妊娠成功的影响提供了基准。
