饲粮蛋白质来源对蛋鸡小肠液组成的影响

Effects of Dietary Protein Source on the Composition of Small Intestinal Fluid of Layer-type Cockerels

本试验旨在通过研究饲粮蛋白质来源对鸡肠液中消化酶活性及离子浓度的影响,为鸡饲料酶学生物学效价评定方法中小肠液的仿生酶谱设计提供决策依据。试验采用2×2完全随机设计,分别选用健康、体重相近的十二指肠瘘、空肠瘘成年海兰褐壳蛋公鸡各24只,将每种类型的荷术鸡随机分成2组,每组4个重复,每个重复3只鸡,分别饲喂玉米-豆粕型饲粮和玉米-豆粕-棉籽粕型饲粮。在试验期第31天、第33天、第35天的09:30至18:30间每隔3h收集1h十二指肠和空肠食糜,通过低温离心的方法制备肠液。结果表明,玉米-豆粕型饲粮条件下十二指肠液脂肪酶活性,Cl-的浓度及空肠液胰蛋白酶的活性显著地高于玉米-豆粕-棉籽粕型饲粮条件下的相应值(P<0.05),而十二指肠液Mg2+浓度和空肠液K+的浓度显著地低于玉米-豆粕-棉籽粕型饲粮条件下的相应值(P<0.05)。从不同肠段肠液组成的差异看,十二指肠液中淀粉酶和胰蛋白酶的活性,Na+、Mg2+的浓度及pH显著地低于空肠液中的相应值(P<0.05),而脂肪酶的活性,K+、Cl-的浓度显著地高于空肠液中的相应值(P<0.05)。这表明饲粮蛋白质来源对鸡肠液蛋白酶活性及电解质离子浓度有显著影响,不同肠段的肠液在组成上存在较大差异。

This study was conducted to investigate the effects of dietary protein source on the composition of small intestinal fluid in layer-type cockerels,which may provide biological basis for simulating small intestinal fluid in feedstuff evaluation using in vitro digestion approach.A 2×2 factorial completely randomized design was adopted.Twenty-four duodenal cannulated and 24 jejunal cannulated Hyline brown layer-type cockerels with similar weight were selected,and the cockerels of each cannulation type were divided into 2 groups with 4 replicates per group and 3 cokerels per replicate.Duodenal or jejunal digesta samples were collected for 1 h every 4 h from 09：30 to 18：30 on day 31,33,and 35 of the experiment.The intestinal fluid was made by centrifuging digesta samples at 4 ℃.The results showed that there were higher trypsin activity and Cl-concentration but lower K＋ concentration in jejunal fluid,and higher lipase activity but lower Mg2＋ concentration in duodenal fluid of cockerel fed corn-soybean meal diet than those of birds fed corn-soybean-cottonseed meal diet （P〈0.05）.The composition of the intestinal fluid from different position of the small intestine showed that the amylase and trypsin activities,Na＋ and Mg2＋ concentrations,and pH were lower,but lipase activity,K＋ and Cl-concentrations were higher in duodenal fluid than those in jejunal fluid （P〈0.05）.There were lower amylase and trypsin activities,but higher lipase activity in duodenal fluid than those in jejunal fluid （P〈0.05）.In conclusion,there were significant effects of dietary crude protein source on the digestive enzymes and ion concentrations in intestinal fluid and significant differences in the composition of intestinal fluid from different positions of the small intestine in layer-type cockerels.