本试验旨在建立肠出血性大肠杆菌O157:H7(E.coli)感染肉鸡动物模型.将100只麻黄羽肉鸡饲喂至7日龄,挑选健康、体质量均一的鸡随机分为6组:空白对照组、A组(1×107 cfu/mL E.coli感染组)、B组(1×108 cfu/mL E.coli感染组)、C组(1×109 cfu/mL E.coli感染组)、D组(1×1010 cfu/mL E.coli感染组)、E组(1×1011 cfu/mL E.coli感染组),每组设3个重复,每个重复5只鸡.感染组每只肉鸡气管滴注大肠杆菌菌悬液0.5 mL,空白对照组肉鸡气管滴注相同体积的磷酸缓冲液(PBS).分别在试验开始前与感染后7d记录肉鸡的体质量,试验期间记录肉鸡的采食量,并观察其临床变化.在感染后7d对肉鸡颈静脉采血以检测肝功能.解剖摘取肉鸡肝脏、脾脏和结肠组织,计算肝脏和脾脏脏器指数,并对肝脏、脾脏和结肠进行载菌量检测和组织病理学观察.结果显示,与空白对照组相比,感染大肠杆菌后肉鸡的料重比和肝脏指数、脾脏指数显著升高(P<0.05),肝脏、脾脏中均检测出大肠杆菌,结肠中大肠杆菌数量明显增多.A～E组肉鸡血清中丙氨酸氨基转移酶(ALT)、总胆红素(T-BiL-V)含量均显著高于空白对照组(P<0.05);D组与E组肉鸡血清中天门冬氨酸氨基转移酶(AST)含量显著高于空白对照组(P<0.05);D组、E组肉鸡血清中总胆汁酸(TBA)含量显著低于空白对照组(P<0.05).病理组织学观察显示,C～E组肉鸡肝脏眼观呈绿棕色,并存在白色坏死点,镜检发现浆液性渗出和红细胞、炎性细胞浸润现象;E组肉鸡脾脏出现明显的毛细血管玻璃样变和毛细血管充血现象;C～E组肉鸡结肠绒毛萎缩、肠壁变薄,同时,D组、E组肉鸡结肠出现毛细血管充血现象.气管滴注可以用于构建鸡的肠出血性大肠杆菌模型,此模型可显著诱导肉鸡肝脏和结肠损伤.
The purpose was to establish a broiler model infected by enterohemorrhagic Escherichia coli O157:H7.One hundred one-day-old Mahuang broilers were randomly divided into 6 groups:control group,group A(1×107 cfu/mL E.coli infection group),group B(1×108 cfu/mL E.coli infection group),group C(1×109 cfu/mL E.coli infection group),group D(1×1010 cfu/mL E.coli infection group)and group E(1×1011 cfu/mL E.coli infection group),with 3 replicates per group and 5 broilers per replicate.Feeding to 7 days of age,broilers in E.coli groups were infected with 0.5 mL E.coli by tracheal instillation,while those in the control group were given the same volume of phosphoric acid buffer(PBS).The body weight before the experiment and 7 days after E.coli infection and the feed intake were recorded,and the clinical changes were observed during the experiment.7 days after infection,blood sample was collected from the jugular vein to detect liver function.The organ index of liver and spleen were calculated.The bacteria carrying capacity and histopathology were observed in liver,spleen and colon.Compared with control group,feed to gain ratio,liver index and spleen index in E.coli broilers were significantly increased(P<0.05).E.coli was detected in liver and spleen,and the number of E.coli in colon increased significantly.Compared with control group,the content of ALT(alanine aminotransferase)and T-bilirubin(total bilirubin)in all E.coli groups were significantly enhanced(P<0.05),and AST(aspartate aminotransferase)content also increased and the TBA(total bile acid)decreased in group D and group E(P<0.05).The histopathological results showed that the broiler liver color in groups C,D and E was greenish brown with white necrotic spots,serous exudation and infiltration of red blood and inflammatory cells by microscopy.The spleen in group E showed obvious capillary hyalinosis and capillary congestion.Intestinal villi atrophy and intestinal wall thinning were observed in groups C,D and E,and capillary congestion was observed in groups D and E.Tracheal instillation can be used to establish a model of E.coli in chickens,which can cause obvious liver and colon damage.
牟芮玮;郭琰娜;卢梦涵;梁少姗;杨绵泽;何永明;唐陆平
佛山科学技术学院生命科学与工程学院,广东佛山 528225
畜牧业
肠出血性大肠埃希菌;气管滴注;肉鸡;动物模型
enterohemorrhagic Escherichia coli;tracheal instillation;broiler;animal model
《中兽医医药杂志》 2024 (003)
21-27 / 7
广东省现代农业产业技术体系创新团队建设专项资金(2022KJ119,2023KJ119)
10.13823/j.cnki.jtcvm.2024.017
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