The Study of Egg Quality and Infected State in "817" Breeding Chicken Infected by Newcastle Disease Virus
|Keywords||Atypical Newcastle disease “817” Breeding birds Diagnosis Carryingvirus Virus isolation|
Newcastle disease (ND) caused by Newcastle disease virus (NDV) is an acute,highly contagious and deadly infectious disease. In our country and even the world,ND have made serious economic loss. When breeding hens infected by NDV virulentstrain, they would appear a untypical clinical symptoms and autopsy change, such aslow mortality rate, inhibiting layers rate, declining the rate of fertilization, highembryo mortality, and more weak young chicks. To validate the contact between theappearance of egg and output rate, fertilization rate, hatching rate, the rate of youngrelations and to test whether new layers carry virus and the proportion whenNewcastle disease virus infection breeding hens. We make this study to identify thequality of the egg in the different period from rehabilitation hens of atypical ND. Italso can lay a theoretical basis for studying etiology of ND.In this study, we diagnosis two “817” chicken group suspected infection atypicalND by usingcomprehensive methods including pathology, serology and etiologicalmethods.The results show that: two chicken group have same clinical symptoms,breathing difficulty, gastrointestinal clinical change and reducing ability of layingeggs; some serious chicken appear gastrointestinal and respiratory hemorrhagiccatarrhal inflammation changes, follicle congestion and hemorrhage, tubal atrophy.,which are consistent with symptoms and autopsy change caused by NDV infection;and we also observed some histopathological changes that can prove NDV infectionsuch as encephalitis, lymphoid tissue necrosis, etc.; Significant rise of the testing HIantibody titer after NDV infection; Separation, identification and immune tissuepathology detection of NDV prove positive. All of the results of NDV infection canindicate NDV infection. Through the above comprehensive diagnosis methods, wediagnose the two “817” chicken atypical group NDV infection.After feed intake of the above two chicken group returned to normal,110eggs each were randomly taken at14d,28d after rehabilitation. Each10of110weretested ND antibody and the rest200eggs hatching after disinfection treatment.Fromthe third day of hatching, we remove the white eggs, die embryo and take detailedrecords. Remove allantoic fluid and keep it in-20℃, Live embryo were taken into-20℃refrigerator to death at the20th d. remove allantoic fluid, processing embryo inbechtop and keep them in-20℃. Will get the disease material separately carried onthe virus serology experiment, NDV separation identification and Real-time RT-PCR testing methods. The results show that the hatching egg have high yolk antibodytiter, shell quality and shape of white egg are abnormal, allantoic fluid do not havehemagglutination ability, disease material are negative by Real-time RT-PCRtesting methods. However the disease materials were vaccinated MDCK cells andBHK-21,14cases of them can appear CPE.The test results show that “817” chicken meat in infection atypical ND, in a longtime, its output kind the egg quality decline, fertilization rate and hatching rate drop,yield weak young rate increased significantly. If the yolk protein antibody levelshigher, the virus-positive rate of eggs is very low, detection of protein sample limitedcircumstances it is difficult to detect NDV. The chickens were pathogenesis in earlytime, this is mainly with eggs, incubation and hatching process by the NDV pollution.Embryonic or embryonic viscera disease material inoculated MDCK andBHK-21cells which can cause obvious CPE, but Newcastle disease virus was notdetected, and specific induced reasons to be further studied.Test results for the correct evaluation of atypical ND illness breeder andNewcastle disease pathogenesis has certain reference value.