中文摘要：

本试验旨在研究妊娠后期胎儿宫内生长受限（Intrauterine growth retardation, IUGR）对蒙古绵羊胎儿胸腺及其T淋巴细胞发育的影响。选择健康的蒙古绵羊42只（经同期发情受孕），在妊娠90 d时选择6只母羊进行屠宰，其余按体质量随机分配到3个组：限制组1 （RG1,0.175 MJ·kgW-0.75·d-1（n=14））、限制组2 （RG2,0.33 MJ·kgW-0.75·d-1（n=12））和自由采食组（CG,0.67 MJ·kgW-0.75·d-1，（n=10）），进行不同能量水平饲养。至妊娠140 d，各组再选择6只母羊进行屠宰。结果表明，妊娠后期限饲母羊严重限制了限饲组胎儿体质量（P〈0.01），导致RG2（P〈0.05）、RG1组（P〈0.01）胎儿胸腺质量、胸腺皮质厚度、胸腺总DNA含量以及RG1组胎儿胸腺的皮质/髓质比值、总蛋白质含量显著低于CG组（P〈0.01）；RG1组胎儿胸腺的SOD酶活性（P〈0.05）、T-AOC浓度（P〈0.01）显著低于CG组，GSH-PX酶活性（P〈0.05）、MDA浓度（P〈0.05）显著高于CG组；RG2、RG1组胎儿的胸腺中CD4＋CD8＋双阳性T淋巴细胞均显著低于CG组（P〈0.05）。结果显示，妊娠后期IUGR严重影响了胎儿胸腺及其T淋巴细胞的生长发育，这必将影响IUGR胎儿细胞免疫能力及出生后的健康。

英文摘要：

This study investigated the effects of IUGR （Intrauterine growth retardation） during late pregnancy on the fetal thymus and the T cell lymphocyte development of Mongolia ovine. 42 Mongolia ewes mated at a synchronized estrus were selected and among them 6 ewes were slaughtered at the beginning of the experiment and the remaining 36 animals were allocated to three different groups： restricted group1 （RG1, 0.175 MJ·kgW-0.75·d-1, n=14）, restricted group2 （RG2, 0.33 MJ·kgW-0.75·d-1, n=12） and control group （CG, ad libitum, 0.67 MJ·kgW-0.75·d-1, n=10）. At 140 d of gestation, 6 ewes in each group were slaughtered and their fetuses were removed. The results showed that the fetal weight in both RG1 and RG2 groups were significantly reduced（P〈0.01） by maternal under-nutrition during late pregnancy, which led to fetal thymus weight, thymus cortical thickness, thymus DNA contents in RG1（P〈0.01） and RG2（P〈0.05） groups, and thymus cortical/medullary ratio, protein contents in RG1（P〈0.01） were decreased compared to that in CG group. The activities of SOD（P〈0.05） and the contents of T-AOC（P〈0.01） of fetal thymus in RG1 group were decreased, while the activities of GSH-PX and the contents of MDA were increased compared to CG group（P〈0.05）. Additionally, the CD4＋CD8＋ T lymphocyte subsets of fetal thymus were lower in both RG2 and RG1 groups than that in CG group（P〈0.05）. These results indicate that the fetal thymus and T lymphocyte are affected seriously by IUGR during late pregnancy, which may influence fetal immunity capability and postnatal health.