谷氨酰胺对热应激条件下肉鸡生产性能、肠道消化酶活和形态结构的保护作用

Protection of Glutamine Supplementation to Performance,Intestinal Enzyme Activity and Morphosis in Broiler under Heat Stress

研究外源性谷氨酰胺(Gln)对热应激条件下肉鸡生长性能、小肠消化酶活和形态结构的保护作用。240只35日龄健康AA鸡(公母各半)随机分成4组,每组3个重复。Ⅰ组为对照组(舍内气温23℃),饲喂基础日粮,Ⅱ、Ⅲ、Ⅳ组为热应激组(舍内气温28℃),分别饲喂基础日粮中添加0、0.5%和1.0%Gln的试验日粮,于42日龄时对肉鸡生产性能、消化酶活和小肠形态结构进行分析。研究结果表明,与对照组相比,热应激处理(Ⅱ组)降低了增重、采食量、饲料转化率,十二指肠和空肠的相对重、绒毛高度、肠腺长度和肌层厚度,空肠的绒毛宽度,回肠的绒毛高度和肠腺长度、淀粉酶和总蛋白酶活性(P<0.01或0.05);提高了十二指肠和空肠的固有层厚度(P<0.01或0.05)。与未添加Gln的热应激组(Ⅱ组)相比,0.5%和1.0%Gln明显缓解了热应激对以上各指标的影响(P<0.05或0.01),且并达到了与对照组(Ⅰ组)接近或不存在差异显著性(P>0.05)的水平。说明外源性Gln能有效保护本试验热应激条件下肉鸡的生产性能、消化酶活和小肠形态结构的正常。

The protective effects of glutamine （Gin） supplementation on growth performance, intestinal digestive enzyme activity and morphosis in broilers exposed to high ambient temperature were evaluated. 240 35 - day - old Arbor Acres broilers （half male and female） were randomly assigned to four treatment groups （3 repeat cages of 20 chicks per cage） in a completely randomized design. Broilers were kept in a temperature-controlled room at either 23 ℃ （no stress, NS, group Ⅰ） or 28 ℃ （heat stress, HT, other groups） for whole day and fed a basal diet or the basal diet supplemented with different levels of Gin （0, 0.5% and 1.0% Gin of diet for group Ⅱ,Ⅲand Ⅳ, respectively）. The growth performance, intestinal digestive enzyme activity and morphosis in 42 - day - old broiler were analyzed. Results show, compared with the NS, the 0 Gin supplementation in diet of HT group Ⅱ decreases body weight gain, feed intake, feed conversion rate, relative weight, villus height, intestinal gland length and muscle layer thickness of duodenum and jejunal, villus width of jejunal, villus height and intestinal gland length of ileum, amylase and gross protease activity （P 〈 0.01 or 0. 05）, and increases lamina propria thickness of duodenum and jejunal. Compared with the HT group Ⅱ （0% Gin）, 0.5% and 1.0% Gin supplementation alleviate heat stress - related deterioration in all the experimental indexes （P 〈 0.01 or P 〈 0.05） and there exists approximation or no difference （ P 〉 0.05） of most indexes among the NS group, HT group Ⅱ （0.5% Gin） and Ⅲ （1.0% Gln）. It is concluded that a combination of dietary Gin supplementation could obviously relieve heat stress - related deterioration in growth performance, digestive enzyme activity, and small intestine morphosis of broilers.