Pregnancy in sheep is a physiological condition characterized by a significant increase in energy demand to ensure adequate foetal growth and development, making them susceptible to oxidative stress. The aim of this study was to analyse the markers of oxidative stress in sheep during pregnancy, parturition and close to peripartum (up to 48 h postpartum), comparing single with twin gestation. Sixty healthy Dorper ewes from 2 to 5 years’ old raised under semi-intensive management were used in this study. Ewes were grouped based on foetal number: Group 1, with single pregnancy (n = 30); Group 2, with a twin pregnancy (n = 30). Blood samples were collected nine times: after artificial insemination (D0, control); at 30 days (D30), 90 days (D90), 120 days (D120), 130 days (D130), and 140 days (D140) of pregnancy; on the day of delivery (DD); at 24 h (PD1) and 48 h (PD2) post-delivery. The concentrations of reduced thiol groups (-SH, P = 0.0155), the enzymatic activities of superoxide dismutase (SOD, P = 0.0009), glutathione peroxidase (GSH-Px, P = 0.0110) and catalase (CAT, P = 0.0001) differed according to fetal number by time. Twin gestation decreased concentration of thiobarbituric acid reactive substances (TBARS; P = 0.0278), and TBARS had differed over time (P < 0.0001), but a fetal number by time interaction was not detected (P = 0.2413). Overall, at peripartum period, there was a higher concentration of SOD and glutathione (-SH and GSH-Px), revealing changes on oxidation and antioxidant activity. TBARS concentration was affected by the number of foetus, considering all experimental periods. In conclusion, as gestation progress, the challenges related to the antioxidant status are more pronounced, especially for twin pregnancy, at the final third of gestation.

绵羊怀孕是一种生理状况，其特征是能量需求显着增加，以确保适当的胎儿生长和发育，使它们容易受到氧化应激的影响。这项研究的目的是分析妊娠，分娩和接近产期（产后48小时）内绵羊的氧化应激标志物，比较单胎和双胎妊娠。在这项研究中，使用了半精养下养育的2至5岁的60头健康的多珀母羊。母羊根据胎儿数量进行分组：第1组，单胎妊娠（n = 30）；第1组。第2组，双胎妊娠（n = 30）。采集血样九次：人工授精后（D0，对照）；在怀孕30天（D30），90天（D90），120天（D120），130天（D130）和140天（D140）时; 在交货当天（DD）；分娩后24小时（PD1）和48小时（PD2）。还原巯基的浓度（-SH，P  = 0.0155），超氧化物歧化酶（SOD，P  = 0.0009），谷胱甘肽过氧化物酶（GSH-Px，P  = 0.0110）和过氧化氢酶（CAT，P  = 0.0001）的酶活性随时间而异。双胎妊娠降低了硫代巴比妥酸反应性物质的浓度（TBARS；P  = 0.0278），TBARS随时间变化（P  <0.0001），但未检测到按时间相互作用的胎儿数（P = 0.2413）。总体而言，在围产期，SOD和谷胱甘肽（-SH和GSH-Px）的浓度较高，表明其氧化和抗氧化活性发生了变化。考虑到所有实验时期，TBARS浓度受胎儿数量的影响。总之，随着妊娠的进行，与抗氧化剂状态有关的挑战更加明显，特别是对于双胞胎妊娠，在妊娠的最后三分之一。