含硫氨基酸对断奶仔猪肠道功能与上皮更新的影响及机制研究

断奶应激是制约断奶仔猪生长的重要因素,影响了仔猪小肠上皮细胞更新及肠道功能的发挥。含硫氨基酸不仅是蛋白质的组成成分，而且在机体重要物质合成和抗氧化方面也发挥关键作用。研究表明含硫氨基酸能够改善新生仔猪肠道抗氧化能力和形态结构、促进小肠上皮细胞增殖。我们的前期研究表明，氧化损伤是影响断奶仔猪肠道功能一个重要因素，且含硫氨基酸可以改善过氧化氢对猪小肠上皮细胞IPEC-1造成的氧化损伤。然而，含硫氨基酸对断奶仔猪肠道功能与上皮细胞更新的影响尚不清楚。因此，本项目以21日龄断奶仔猪为试验对象，研究含硫氨基酸对断奶仔猪小肠粘膜形态结构、刷状缘消化酶活性、营养物质转运与转运载体表达、肠道上皮屏障与紧密连接蛋白表达的影响，并通过免疫组化和蛋白质组学等手段进一步研究含硫氨基酸对仔猪小肠上皮更新的影响及其内在机制，为确定断奶仔猪肠道理想含硫氨基酸需要量和完善仔猪肠道损伤的营养干预手段提供科学依据。

Weaning stress, which jeopardizes intestinal epithelial cell turnover and intestinal function, is an important factor resulting in growth retardation of piglets. Besides the role in protein synthesis, sulfur amino acids (SAA) play key roles in important molecules biosynthesis and anti-oxidant capacity. It was reported that SAA were able to improve intestinal anti-oxidant capacity and morphology and enhance epithelial cells proliferation of neonatal piglets. Our previous studies showed that oxidative damage was one of the causes of intestinal dysfunction, and SAA has beneficial effects on hydroperoxide-damaged IPEC-1 cells. However, the effects of SAA on intestinal functions and epithelial turnover of weaning piglets are still unclear.Therefore, the present project will focus on the effects of SAA on the intestinal morphology, activities of enzymes associated with the digestive functions, nutrients transportation and transporters expression, barrier function and tight junction protein expression of 21 days weaning piglets. The effect of SAA on epithelial cell turnover and the potential mechanism were also tested using immunohistochemistry and proteomics. Our results will provide scientific basis for intestinal SAA requirement in weaning piglets and improving nutritional means for repairing injury intestine of piglets.