急性热应激对肉仔鸡肠道屏障分子、营养转运蛋白和腺苷酸活化蛋白激酶的影响

Effects of Acute Heat Stress on Intestinal Barrier Molecule,Nutrient Transporter and Adenosine Monophosphate Activated Protein Kinase of Broilers

本试验从肠道屏障、营养物质转运和腺苷酸活化蛋白激酶(AMPK)信号通路3个方面探究了急性热应激对肉仔鸡肠道功能的影响。试验选取80只体况基本一致的28日龄健康爱拔益加肉仔鸡,随机分成热应激组和对照组(每组8个重复,每个重复5只鸡)。热应激组08:00—18:00进行10 h急性热应激,室温为(35±1)℃,对照组室温为(23±1)℃。热应激结束后,每重复各取1只鸡采集血清和空肠黏膜样品。统计肉仔鸡生产性能,测定血清葡萄糖(GLU)、总胆固醇(TCHO)、甘油三酯(TG)和内毒素(ET)含量,检测空肠黏膜中闭合蛋白-1(claudin-1)、闭锁蛋白(occludin)、闭合小环蛋白-1 (ZO-1)、阳离子氨基酸转运蛋白-1(CAT-1)、小肽转运蛋白-1 (PepT-1)、葡萄糖转运蛋白-2 (GLUT-2)、肝激酶B1 (LKB1)和AMPKα1基因的相对表达量。结果表明:1)与对照组相比,急性热应激显著降低肉仔鸡的平均采食量和平均体增重(P<0.05),显著提高料重比(P<0.05)。2)与对照组相比,急性热应激显著提高肉仔鸡血清ET含量(P<0.05),对血清GLU、TG和TCHO含量无显著影响(P>0.05)。3)与对照组相比,肉仔鸡空肠黏膜ZO-1基因的相对表达量在急性热应激后显著上升(P<0.05),急性热应激对肉仔鸡空肠黏膜occludin和claudin-1基因的相对表达量无显著影响(P>0.05);急性热应激对肉仔鸡空肠黏膜CAT-1、PepT-1和GLUT-2基因的相对表达量无显著影响(P>0.05);急性热应激显著上调了肉仔鸡空肠黏膜LKB1基因的相对表达量(P <0.05),有上调肉仔鸡空肠黏膜AMPKα1基因相对表达量的趋势(P=0.060 3)。由此可知,急性热应激显著降低肉仔鸡生长性能,损伤肠道屏障,但对肠道氨基酸、小肽及GLU的转运没有造成影响;急性热应激影响肉仔鸡肠道LKB1基因的表达。

The study aimed to investigate the effects of acute heat stress on the intestinal function of broilers from three aspects as intestinal barrier,nutrient transport and adenosine monophosphate activated protein kinase(AMPK)signaling pathway.A total of 80 healthy 28-day-old Arbor Acres broilers with similar weight were randomly allocated into a heat stress group and a control group with 8 replicates per group and 5 chicks per replicate.The ambient temperature in the heat stress group was(35±1)℃from 08:00 to 18:00 for 10 hours heat stress treatment,and the ambient temperature in the control group was(23±1)℃.After the heat stress treatment,1 chick per replicate was sacrificed,and jejunum mucosa and serum samples were excised.Meanwhile the growth performance,the contents of serum glucose(GLU),total cholesterol(TCHO),triglyceride(TG)and endotoxin(ET),and the relative gene expression levels of occludin,claudin-1,zonula occluden-1(ZO-1),cationic amino acid transporters-1(CAT-1),peptide transporter-1(PepT-1),glucose transporter-2(GLUT-2),liver kinase B1(LKB1)and AMPKα1 in jejunum mucosa of broilers were detected.The results showed as follows:1)compared with the control group,acute heat stress significantly reduced the average body weight gain and the average feed intake(P<0.05),while significantly increased the ratio of feed to gain(P<0.05)of broilers.2)Compared with the control group,the acute heat stress significantly increased serum ET content(P<0.05),but no significant changes were detected on the contents of serum GLU,TG and TCHO(P >0.05)of broilers.3)Compared with the control group,the relative gene expression level of ZO-1 was significantly increased after acute heat stress(P<0.05),but the acute heat stress did not significantly affect the relative gene expression levels of claudin-1 and occludin in jejunum mucosa(P >0.05)of broilers;the acute heat stress did not significantly affect the relative gene expression levels of CAT-1,PepT-1 and GLUT-2 in jejunum mucosa of broilers(P >0.05);the relative gene expression level of LKB 1 in jejunum mucosa of broilers was significantly increased after acute heat stress(P<0.05),and the relative gene expression level of AMPKα1 in jejunum mucosa of broilers tended to be increased by the acute heat stress(P=0.060 3).In conclusion,the acute heat stress can significantly reduce the growth performance,damage the intestinal barrier,but do not affect the transport of amino acids,oligopeptide and GLU in intestine of broilers.Besides,the acute heat stress can affect the expression of LKB1 in jejunum mucosa of broilers.