环江香猪宫内生长受限孕体的营养素转运与代谢特性研究

Intrauterine growth retardation (IUGR) of fetus reduces the survival rate, growth performance, and carcass composition of offspring, which cause serious economic losses to the pig production. It is great significant to study the genesis mechanism and develop the control measures for IUGR to the pig industry. The piglets with IUGR present the serious changes of morphology, metabolism, and physiological functions of tissues and organs, but the development stage and sequence of these changes occurred is not clear. The pregnant Huanjiang mini-pigs on days 40, 75, and 110 after service were used in this study. In order to reveal the developmental variation of intestinal and placental transport ability for nutrients in IUGR fetus, the differences of biochemical parameters, nutrients and metabolites of allantoic and amniotic fluids in the normal fetus and IUGR fetus will be compared; in order to reveal the development variation of nutrient metabolism ability in IUGR fetus, the differences of the mRNA and protein expression levels and activities of nutrient-metabolic enzymes of placenta, jejunum, liver, and Longissimus muscle in the normal fetus and IUGR fetus will be determined. The key nutrients and their metabolites related to IUGR genesis will be screened out, and the effects of these nutrients and metabolites on proliferation activities, apoptosis, nutrient uptake and metabolism of porcine embryonic trophectoderm cells and their regulatory pathways will be explored. The aim of this study is to elucidate the physiological and biochemical mechanism of IUGR genesis at the nutrient transport and metabolism levels, and screen out the key nutrients and their metabolites related to IUGR genesis, in order to provide the basis for the high-efficient production of Chinese mini-pigs.

胎儿宫内生长迟缓（IUGR）会降低后代的成活率、生长性能和胴体组成，给养猪业带来严重损失，研究IUGR的发生机制与防治措施对养猪业具有重要意义。IUGR仔猪的器官形态结构与生理功能会发生改变，但其出现的发育阶段和先后顺序尚不清楚。本项目选用不同妊娠期的环江香猪，比较正常发育胎猪和IUGR胎猪羊水和尿囊液中生化参数、营养素及其代谢物的差异，揭示IUGR胎猪肠道和胎盘转运营养素能力的变化规律；测定正常发育胎猪和IUGR胎猪胎盘及其空肠、肝脏和背肌中营养素代谢酶表达和活性的差异，揭示IUGR胎猪代谢营养素能力的变化规律；筛选出与IUGR发生相关的营养素及其代谢物，并验证其对猪胚胎滋养外胚层细胞的增殖、凋亡、营养素转运和代谢的调控作用及其调节通路，从营养素转运和代谢层面阐明IUGR发生的生理生化机制，筛选出与IUGR发生相关的关键营养素及其代谢物，为研发我国小型猪高效生产技术提供依据。

胎儿的生长发育受多种因素影响，胎儿宫内生长迟缓（IUGR）会降低后代成活率、生长性能和胴体组成，给养猪业带来严重损失。研究IUGR发生机制与防治措施对提高养猪业经济效益具有重要意义。本项目研究了不同妊娠期环江香猪母猪的繁殖性能、体成分和血浆代谢组特征，不同妊娠期、不同体重胎猪体成分及其对应胎液代谢物、胎盘化学组成和转录组特征的差异性变化规律，并阐明了IUGR发生的生理生化机制，筛选出了多种孕体发育关键调控物质。结果表明：随妊娠期延长，母猪血浆ALT、ALB、AMM、CHE、HDL-C和BIL等生化参数及Leu、Ile、Glu、Tau和Orn等游离氨基酸（FAA）含量发生显著变化；胎猪体重、干物质和粗脂肪含量显著升高，氨基酸和脂肪酸（FA）含量发生显著变化；妊娠天数显著影响羊水和尿囊液生化参数和大部分FAA含量及胎盘多胺、FAA和FA含量；胎猪体重显著影响胎猪Lys、Glu、Tyr、NEAA、TAA和EAA等氨基酸及大部分FA含量，羊水和尿囊液部分生化参数和大部分FAA含量及胎盘精胺、FAA及C14:0、C17:0、C18:1n9c、C20:3n6和C20:4n6等含量。不同妊娠期母猪血浆差异代谢通路与氨基酸、FA和糖代谢相关，共同差异代谢通路为组氨酸代谢通路。不同妊娠期胎猪对应胎盘的差异基因主要富集在氨基酸合成和叶酸生物合成通路，而不同体重胎猪对应胎盘的差异基因主要富集在细胞色素P450对异种生物的代谢作用、IgA产生的肠道免疫网络、酪氨酸代谢和矿物质吸收等通路。WGCNA分析得出，CEP120、MECOM、GPR63、KCNJ13和DMGDH与体重呈正相关、与腐胺呈负相关，SNX31与体重呈负相关、与腐胺呈正相关。本项目研究结果不仅对提高胎猪存活率具有重要理论和实践意义，而且对指导其它哺乳动物妊娠期营养供给、预防IUGR发生具有重要参考价值。

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