精胺调控哺乳仔猪肠道发育的代谢组学研究

One of the problems faced by the pig-raising industry in China is the fact that the defective development of suckling piglets' intestinal canals restricts their growth. Previous researches both home and abroad have indicated that spermine can promote the development of suckling piglets' intestinal canals and thus improve their growth performance. However, it is yet unclear how spermine influences the metabolism of piglets. The current project borrowed the research ideas of nutrimetabolomics, a newly-emerged interdisciplinary subject to systematically investigate into how suckling piglets' metabolome like intestinal mucosa and biofluid dynamically responds to spermine. It aims to answer the following questions: (1) What kind of influence will spermine has on the matabolomic process of suckling piglets? (2) Whether such influences are correlated with the development and maturity of piglets' intestinal canals? A qualitative and quantitative analysis will be carried out on the metabolite of endogenous small molecules, and combing the results with pattern recognition techniques (like PCA, PLS-DA, O-PLS-DA, etc.) based on multi-variable statistics and multivariate statistical analysis methods (like pearson correlation coefficient, etc.), biomarkers and potential key metabolic molecules will be selected.Metabolic network databases (KEGG, etc.) can be referred to in order to decide and investigate the metabolic procedures involved in the changes of related metabolites. Further techniques like RNA interference technique and RT-PCR will be used to verify the function of key metabolic molecules and thus to reveal the molecular mechanism underlying spermine's function for regulating the maturity of suckling piglets' intestinal canals. The research results are believed to be of practical value in their application in the pig-raising industry.

幼龄仔猪肠道发育不健全制约生长性能是当前我国养猪业生产难题之一。国内外文献表明：精胺促进哺乳仔猪肠道发育和改善了生长性能。但尚不清楚精胺如何影响哺乳仔猪的代谢活动。本项目借助营养代谢组学这一新兴交叉学科的创新研究思路，系统研究哺乳仔猪肠道黏膜、体液等代谢组对精胺作用的动态应答。旨在回答：精胺对哺乳仔猪代谢过程会产生怎样影响，这些影响与其肠道发育的相关关系如何等问题。对内源性小分子代谢产物进行定性定量分析，结合多变量统计为基础模式识别技术（PCA、PLS-DA、O-PLS-DA等）和多元统计分析（皮尔森相关系数分析等），筛选出与肠道发育相关的生物标志物和潜在的关键代谢分子。通过代谢网络数据库（KEGG等）确定和研究相关代谢物变化涉及的代谢途径。进一步采用RNA干扰技术、RT-PCR等技术对关键代谢分子进行功能性验证。揭示精胺调控幼龄哺乳仔猪肠道发育分子机制。研究结果在养猪业有实际应用价值。

幼龄动物肠道发育不健全制约着动物的生长发育及健康。研究表明精胺能促进哺乳动物肠道发育、改善其生长性能，但精胺及其前体物质对哺乳动物在早期断奶或氧化应激条件下机体代谢情况影响尚不清楚。据此，本项目借助营养代谢组学这一新兴交叉学科的创新研究思路，系统研究了动物肠道、体液等代谢组在精胺及其前体物质作用下的动态应答等。结果显示：1）精胺能显著提高哺乳仔猪断奶后肠道形态学、酶活，调控了血清氨基酸代谢，小肠能量代谢、氨基酸代谢以及微生物代谢，从而促进了肠道发育。2）精胺能降低仔猪血清、空肠、回肠、脾脏和胸腺中脂质过氧化和蛋白氧化，提高酶性和非酶性抗氧化系统活力；上调了空肠、回肠、脾脏和胸腺酶性抗氧化基因及Nrf2基因的mRNA水平，下调了Keap1基因的mRNA水平；精胺降低了仔猪血清中促炎症因子水平以及空肠、回肠、脾脏和胸腺促炎症因子的基因表达，提高了抗炎症因子和mTOR基因转录水平；精胺增加了脾脏和胸腺中cyclinA2基因表达，下降了p21和cyclinD3基因表达水平。3）精胺能提高哺乳和断奶仔鼠肠道发育，抗氧化能力以及调控其肠道脂质代谢、氨基酸代谢及微生物活力。4）精胺对氧化应激仔鼠肠道形态有改善作用；精胺能显著提高仔鼠肠道、脾脏和肝脏抗氧化能力，调控了回肠代谢。5）氧化应激条件下，精胺前体物质（精氨酸及精氨酸前体物）显著改善了大鼠肠道形态；精氨酸、谷氨酰胺和N-氨甲酰谷氨酸能降低大鼠肠道脂质过氧化，提高酶性和非酶性抗氧化物质活力；精氨酸、谷氨酰胺和N-氨甲酰谷氨酸能够显著改变大鼠血浆和尿液脂质、氨基酸和能量类代谢底物。这些研究结果表明，精胺及其前体物质能够促进动物肠道发育，提高机体抗氧化状态和免疫力，能有效调控断奶应激和氧化应激所造成的机体代谢异常，保护动物健康。项目结果不仅能科学阐明精胺与哺乳动物断奶后机体健康关系，还可为精胺能作为养猪业中的一种有效的机体保护添加剂提供理论依据。