玉米和玉米淀粉对断奶仔猪肠道屏障的影响

Effect of maize and maize starch on intestinal barrier of weaned piglets

旨在探究玉米和玉米淀粉对断奶仔猪肠道屏障的影响及其分子机制。将72只28日龄断奶大白猪随机分为2组,每组2个重复(公、母各半),每个重复18只,分4栏饲养。分别饲喂玉米饲料和玉米淀粉饲料,预饲7d,正式试验21d。试验结束时检测断奶仔猪的生长性能、血清生化指标、消化道pH值、肠道绒毛形态、相关基因和信号通路的表达。结果显示,淀粉组仔猪平均日增质量和体质量显著低于玉米组(P<0.05),平均日采食量减少。血液生化检测结果显示,与玉米组相比,淀粉组血清谷草转氨酶(AST)、乳酸脱氢酶(LDH)的活性及总蛋白(TP)、白蛋白(ALB)、甘油三酯(TG)含量显著降低(P<0.05),γ-谷氨酰转肽酶(γ-GT)的活性、高密度脂蛋白胆固醇(HDL-C)和总胆固醇(TC)含量极显著降低(P<0.01),表明机体代谢受到抑制。淀粉组十二指肠pH值极显著上升(P<0.01),且HE切片显示十二指肠绒毛密度和细胞数明显减少。QRT-PCR检测肠道黏膜相关基因结果显示,与玉米组相比,淀粉组尾型同源盒基因(CDX2)和肿瘤坏死因子(TNFα)mRNA表达量显著下调(P<0.05),增殖细胞核抗原(PCNA)、闭锁蛋白(OCLN)和闭合蛋白(CLDN1)mRNA表达量极显著下调(P<0.01),表明肠道屏障发育受到抑制。Wnt信号通路活性检测显示,淀粉组Wnt家族成员10b(Wnt10b)、β-连环蛋白(β-catenin)和细胞周期大蛋白(Cyclin D1)mRNA表达量极显著下调(P<0.01),与蛋白检测结果相符,表明仔猪肠道黏膜Wnt/β-catenin信号通路活性受到抑制。综上所述,相对于玉米饲料,玉米淀粉饲料会抑制Wnt/β-catenin信号通路抑制肠道屏障的发育影响肠道健康,进而影响仔猪的生长性能。比较2组饲料的营养成分,其中淀粉组中性洗涤纤维(NDF)含量低于玉米组,其可能是抑制Wnt/β-catenin信号通路影响肠屏障发育的主要因素之一。

This experiment aimed to investigate the effect of maize and maize starch on the intestinal barrier of weaned piglets.Seventy-two 28-day-old weaned Large White pigs were randomly divided into two groups of two replicates each(half male and half female),18pigs in each replicate,and kept in four pens.The piglets were fed maize and maize starch diets,pre-fed for 7d,and formally tested for 21d.At the end of the experiment,the growth performance,serum biochemical indexes,digestive pH,intestinal morphology,expression of related genes,and signaling pathways of the weaned piglets were detected.The results showed that the average daily weight gain and body mass of piglets in the maize starch group were significantly lower than those in the maize group(P<0.05),and the average daily feed intake was reduced.The results of the biochemical blood assay revealed that the levels of serum total protein(TP),albumin(ALB),glutamate transaminase(AST),lactate dehydrogenase(LDH),and triglyceride(TG)were significantly lower(P<0.05)in the maize starch group compared with the maize group.Furthermore,the levels ofγ-glutamyl transpeptidase(γ-GT),high-density lipoprotein cholesterol(HDL-C),and total cholesterol(TC)were highly significantly lower(P<0.01),indicating that the metabolism of the organism was inhibited.The pH of the duodenum was significantly increased in the maize starch group(P<0.01),and HE sections showed a significant decrease in duodenal villus density0 m374 and cell count.qRT-PCR assay for intestinal mucosa-related genes showed that caudal type homeobox 2(CDX2)and tumor necrosis factor(TNF)relative mRNA levels were significantly downregulated(P<0.05),and proliferating cell nuclear antigen(PCNA),occludin(OCLN)and claudins(CLDN1)relative mRNA levels was highly significantly downregulated(P<0.01).The Wnt signaling pathway activity assay showed that the relative mRNA levels of Wnt10b,β-catenin,and cyclin D1were highly significantly downregulated(P<0.01)in the maize starch group compared with the maize group,which was consistent with the protein assay results,indicating that the Wnt signaling pathway activity in piglet intestinal mucosa was inhibited.In conclusion,a maize starch diet can inhibit intestinal mucosa development by suppressing the Wnt/β-catenin signaling pathway and affecting intestinal health,affecting piglet growth performance.