| Reticuloendotheliosis, which is caused by reticuloendotheliosis virus (REV), can lead tostunting syndrome, formation of acute reticular cells tumor, formation of chronic tumor inlymphoid tissue and other tissues in chickens, turkeys, ducks and other poultries. REVinfection can not only cause tumors, they can also cause atrophy of immune organs (likechicken thymus and bursal) of infected chicken. REV will make the chicken’s immunefunction decline, or even lost, lead to immunosuppression. The infection chickens arevulnerable to other virus diseases, bacterial diseases and easy to have secondary infection. Inour country, REV infection was reported to be very common in chicken flocks. In this study,we compared the production performance of REV infected chicken and healthy chicken froma chicken farm in Shaanxi province to investigate the effect of Reticuloendotheliosis on theage at first egg, the laying rate and death rate. In addition, we detected antibody titers of NDV,ALV-H9and ALV-H5(RE-4and RE-5) vaccine to acquire the influence of REV-infection onvaccine immunity effects. The objective of this project is to get the information for theprevention and control of reticuloendotheliosis. The test results are as follows:1. ELISA method was used to detect REV of the parental chickens and the commercialchickens of a large-scale chicken farm in Shaanxi province. The data indicated that theaverage positive rates of two parental chickens are19.29%and0.27%respectively; theaverage positive rates of two commercial chickens are15.49%and4.89%separately.2. Comparative study for production performance of a REV antibodies positive chickenand a REV negative chicken. Compared with the REV negative chickens, the age at first eggof the positive chickens was respectively later by4d. At week20and23, the laying rate of thepositive chickens fell slightly, but not significantly (P>0.05), in specific, the laying rate of REVpositive chickens and REV negative chickens fell by1.09and4.75respectively. But at week21and22, the difference is significant (P<0.05), they fell by8.08and9.17respectively. Fromweek24to26, the difference is very significant (P<0.01), they fell by12.35,28.62and17.09respectively. In terms of the number of death and elimination, from week1to week2, the number is all about20; the difference is not significantly (P>0.05). From week3to23, thenumber is less than10and less volatile, the difference is not significantly (P>0.05). But fromweek24to week26, the number of death and elimination of REV positive chickens is about50, the REV negative chickens is less than20, the difference is significant (P<0.05).3. To explore the effect of REV infection of chickens on vaccine immune effect. Serumsamples of positive and negative chickens were collected randomly, antibody concentration ofND, H9, H5(Re-4), H5(Re-5) were measured by HI and HA test. The results show that therewas significant difference on the impacts of immune effect of NDV vaccine at day55(P<0.05)and no significant difference at day95, day123, day148and day163(P>0.05). There wassignificant difference on the impacts of immune effect of ALV H9subtype vaccine at day55and day95(P<0.05) and no significant difference at day123, day148and day163(P>0.05).There was very significant difference on the impacts of immune effect of ALV H5subtype(RE-4) vaccine at day55(P<0.01) and significant difference at day95and day123(P<0.05)and no significant difference at day148and day163(P>0.05). There was great difference onthe impacts of immune effect of ALV H5subtype (RE-5) vaccine at day55(P<0.01) andsignificant difference at day95(P<0.05) and no significant difference at day123, day148andday163(P>0.05). It can be concluded that REV infection of ALV vaccine immuno-suppressive effect is more serious than the NDV vaccine. |
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