中文摘要：

为探讨应激对肉仔鸡生产性能影响的机理,本试验用地塞米松模拟应激条件下所分泌的糖皮质激素对肉仔鸡空肠二糖酶及黏膜形态的影响。试验选取21日龄体重相近的Arbor Acres（AA）肉仔鸡36只,随机分为4个处理,其中3个试验组每只腹部皮下注射糖皮质激素类药物地塞米松生理盐水注射液1 mL（地塞米松剂量分别为0.1、1和5 mg/kgBW）,对照组注射等体积的生理盐水,连续注射7 d。结果表明：（1）地塞米松显著抑制了肉仔鸡体增重（P〈0.05）,且随剂量的增大抑制效应增强;（2）地塞米松对肉仔鸡空肠黏膜蔗糖酶和麦芽糖酶活性无显著影响（P〉0.05）;（3）不同剂量的地塞米松显著降低了肉仔鸡空肠绒毛高度、吸收面积和绒毛高度/隐窝深度的比值（P〈0.05）,5 mg/kgBW地塞米松注射组显著增加了空肠隐窝深度（P〈0.05）,但地塞米松未对肉仔鸡空肠绒毛宽度和固有层厚度产生显著影响（P〉0.05）。从本试验结果可推测应激对肉仔鸡生长的抑制可能与糖皮质激素的释放能够降低肠道绒毛高度、吸收面积及增加隐窝深度而损害了肠道的吸收功能有关。

英文摘要：

In order to explore the mechanism by which stress affects the growth of broilers,this trail was designed to investigate the effect of glucocorticoid,one hormone released when animal stressed,on disacchridase activities and mucosa morphology in jejunum of broilers.Thirty-six 21-day-old Arbor Acres broilers with similar weight was randomly assigned into four groups,three of which was injected with 1 mL dexamethasone-saline solution（containing dexamethasone 0.1,1 and 5 mg/kg BW,respectively）.The dexamethasone is a kind of drug like glucocorticoid.The control group was injected with 1 mL saline solution.The result showed that（1） The dexamethasone restrained the growth of broilers significantly,and the effect is depended on the dose of dexamethasone（P〈0.05）.（2） There is no significant differences found in both sucrase and maltase activities between control group and injected groups（P〉0.05）.（3） The dexamethasone decreased the villus height,the absorption area and the value of villus height/crypt depth in broilers＇ jejunum significantly（P〈0.05）.The crypt depth of the group injected with dexamethasone 5 mg/kg BW was significantly deeper than that of control group（P〈0.05）.But dexamethasone don＇t have significant effect on the villus width and lamina propria mucosae thickness（P〉0.05）.The results suggest that the reason of growth restrain of broilers caused by stress may be related to the secretion of glucocorticoid which gives rise to the decreases of villus height,absorption area and the increase of crypt depth,and then impairs the absorption function of intestine.