母源半胱胺传递对母仔猪机体氧化应激损伤的干预效应研究

In modern pig production, many factors can cause oxidative stress on sows and piglets, which decrease the production performance and restrict the development of large-scale swine industry. Fertility of sows is a key factor to evaluate the productivity level of pig farms. Sows during pregnancy, delivery, lactation and piglets at weaning are easy to suffer oxidative stress. It has been a burning issue for researchers to effectively relieve oxidative stress of sows and piglets. Our previous study has revealed that cysteamine could relieve the oxidative stress on weanling piglets. In this project, we investigate the effect of cysteamine on oxidative stress of sows and piglets in various physiological periods, including sows at the late stage of pregnancy, at farrowing, during lactation and piglets during suckling period and at weaning. The aim of this study is to reveal the intervention mechanism of maternal cysteamine delivery on oxidative stress damage, and to provide a new theoretical basis for controlling oxidative stress, promoting the health and keeping the balance of the redox state in the body of sows and piglets.

在现代养猪生产中，许多因素会导致母仔猪机体遭遇氧化应激，引起生产性能降低，继而制约规模化养猪业发展。母猪的繁殖力是衡量猪场生产力水平的关键因素，处于妊娠、分娩、哺乳生理阶段的母猪以及处于断奶阶段的仔猪又极易遭受氧化应激，如何有效缓解母仔猪的氧化应激，一直是研究者们亟待解决的问题。本项目在前期揭示半胱胺具有缓解断奶仔猪机体氧化应激功能的基础上，将母仔猪作为研究整体，依据母仔一体化系统营养调控技术方法，结合建立猪乳腺上皮氧化应激模型，探讨了半胱胺对“妊娠后期母猪-分娩-泌乳母猪-哺乳仔猪-仔猪断奶”机体氧化应激的影响，从而揭示母源半胱胺传递对母仔猪机体氧化应激损伤的干预效应机制，为控制氧化应激，促进母仔猪机体健康，保持体内氧化还原状态平衡提供新的理论依据。

繁殖周期内高产母猪旺盛代谢和机体动员产生大量活性氧所诱导的氧化应激会损害胎猪的存活和出生后的生长发育。日粮来源的抗氧化剂可作为干预母仔猪的氧化应激和繁殖性能的潜在手段。因此，本项目首先比较了妊娠后期和泌乳期母猪补充两种抗氧化剂（半胱胺和N-乙酰半胱氨酸）对母仔猪氧化应激传递的干预效果及繁殖性能的影响; 随后，研究了不同水平半胱胺对母仔猪氧化应激和繁殖性能的干预效应；最后，以猪血管内皮细胞和滋养层细胞为体外模型，采用H2O2和呕吐毒素诱导氧化应激模型研究半胱胺对胎盘血管生成和屏障作用及其作用机理。主要结果如下：（1）500 mg/kg半胱胺和500 mg/kg N-乙酰半胱氨酸缓解了母仔猪-胎盘氧化应激，有效提高了胎盘线粒体生物合成和功能，母猪死胎率分别降低了5.4%和5.1%。其中，半胱胺改善母仔猪氧化应激和降低死胎率的效果优于N-乙酰半胱氨酸。（2）不同水平半胱胺对母仔猪的干预效应不存在明显剂量效应，但低剂量的半胱胺（100 mg/kg）在改善母仔猪氧化应激和提升繁殖性能的效果最优，在生产每头健仔的母猪饲料成本上可降低0.5元。（3）细胞试验揭示了半胱胺对H2O2和呕吐毒素诱导的氧化应激的内皮保护作用和胎盘屏障保护作用与STAT3信号的激活及下游分子（VEGF-A、Occludin和ZO-1）的表达有关。本研究结果不仅揭示了半胱胺可作为日粮来源抗氧化剂调控母仔猪氧化应激和胎盘功能的作用和机制，同时确定了生产中适宜的添加剂量（100mg/kg），为解决母猪繁殖障碍问题提出了科学有效的营养策略。