日粮添加尿素对瘤胃上皮细胞增殖、凋亡以及吸收转运能力的影响

Effects of Dietary Urea Supplementon Rumen Epithelial Cell proliferation,apoptosis and Epithelial Absorption and Transportation

本研究探讨了在日粮中添加尿素替代部分豆粕对山羊瘤胃发酵、上皮细胞增殖、凋亡和吸收转运能力的影响。将18只波杂山羊随机分为3组(n=6),分别饲喂3种日粮:LC组(纯粗料)、MC组(30%精料)以及Urea组(1%DM缓释尿素替代部分豆粕+30%精料)。饲喂Urea组和MC组的山羊瘤胃中短链脂肪酸(SCFA)浓度、pH值均显著高于LC组,而该两组之间无显著差异;但Urea组在MC组的基础上进一步显著提高了瘤胃NH3和血浆尿素氮(BUN)浓度。因此日粮添加尿素对于瘤胃上皮中受瘤胃SCFA浓度、pH值调节的上皮生长、细胞周期、增殖凋亡相关基因和SCFA转运载体mRNA表达的影响与MC组相似,但对受瘤胃NH3调节的尿素转运、细胞内pH(pHi)调节相关蛋白mRNA表达则有显著的抑制效果,即显著高于LC组,但低于MC组。

This study investigated the effects of dietary urea supplement on goat rumen fermentation,epithelial cell proliferation&apoptosis,absorption and transportation of rumen epithelium.18 Boza goats were randomly divided into 3 groups(n=6)and fed with 3 different diets:LC group(only hay),MC group(30% concentrate)and Urea group(1%DM urea replacing soybean meal partly+30% concentrate).The short chain fatty acids(SCFA)concentration and pH in goats rumen in Urea group and MC group were significantly higher than LC group,but there was no significant difference between these two groups.Meanwhile,Urea group had even higher rumen NH3 and plasma urea-N(BUN)concentrations than MC group.Therefore,the effects of dietary urea supplement on epithelium growth,cell cycle,mRNA expression of cell proliferation,cell apoptosis related genes and SCFA transporters which dependent on ruminal SCFA concentration and pH were similar to those in MC group.Comparing with MC group,Urea group had significant inhibitory effects on urea transport across rumen epithelium and intro-cellular pH(pHi)regulator protein mRNA expression which dependent on ruminal ammonia concentration,but those were still significantly higher than LC group.