The Influence Of Anti-Virus Drug And Thiamphenicol Against ALV-J Pathogenicity

Avian Leukosis J was recognized as one infectious neoplastic disease caused by Avian Leukosis virus J(ALV-J) and pathologically characterized by myelocytomas and hemangiomas. The first description of ALV-J in broiler was in England in 1988 by Payne L and, since then, it has been described in almost all white feather meat-type chicken all over the world. In China, ALV-J infection of meat-type chickens, which predominantly promotes the development of myelocytomas, was first reported by Yan Huang in 1999. However, the host range of ALV-J has expanded from meat-type chickens to egg-laying chickens beginning in 2004. Moreover, ALV-J infection of layer chickens was associated with novel tumor type-hemangiomas and promotes the development of a greater spectrum of tumors in chickens,as myelocytoma has also been implicated in some hemangioma cases. Although ALV-J infection caused the enormous economic loss of the poultry industry, there was no vacanation against this disease, only through the purification of the chicken flock. In order to speed up the purification of ALV-J infection and underlie the mechanism of the anti-ALV-J effect of drug, we carry out the activity experiments of ribavirin, moroxydine, astragalan and thiamphenicol against ALV-J in DF1 cell and SPF chickens.The experiments of ribavirin, moroxydine and astragalan on p27 expression influence of ALV-J(NX0101) were carried out by using the CCK 8 test kits detected for the maximum safe concentrations of drugs on DF1 cell and by using ALV-J p27 antigen ELISA test kit for p27 expression. The results showed that the maximum safe concentrations of Ribavirin,moroxydine and astragalan on DF1 cell are respectively 0.039 mg/m L, 0.0625 mg/m L and0.0625 mg/m L. Under the safe concentration scales of drug, the obvious inhibitory concentration against p27 expression of ribavirin was 0.0391mg/mL and astragalan0.0039-0.0625 mg/mL. However, various dose of moroxydine has no inhabitory effect on p27 expression. The aforementioned results showed that ribavirin and astragalan can inhabit the propogation of ALV-J.In order to further verify the early application of astragalan and thiamphenicol on the influence of ALV- J congenital infection, 7-day-old-SPF chicken was inoculated with 1000TCID50 ALV-J through the yolk sac and count the mortality of the SPF embryos during incubation. Then, 105 SPF chickens at 1 day of age were randomly assigned into three groups of 35 each. The experimental group was respectively given with astragalan(100mg/L) andthiamphenicol(100mg/L) lasting for five days, three times with 5 days of the internal, and the last group was negative control. A comprehensive evaluation about astragalan and thiamphenicol on the influence of ALV- J congenital infection was carried out by cloaca detoxification and viremia of ALV-J, vaccine immunization level of ND, the immune organ index and body weight, tumor incidence and histopathological examination. The results indicated that the two drugs had no significant influence on viremia elimination and occurrence of ALV-J antibody and the increase of ND antibody. Similarly, the weight difference between Astragalus group and virus group was not significant at the whole experimental process; Although early weight of thiamphenicol group was obviously higher than that of other two groups, its weight was lower than that of other two groups after 60 d.the significant deduction of peripheral blood leucocyte/lymphocyte at 6d and immune organ index of the spleen and bursa of fabricius at 42 d in thiamphenicol group was observed compared with the other two groups. Furthermore, tumors incidence at thiamphenicol group was the highest, 28.57%(10/35), followed by infection control group 20%(7/35) and astragalus group 11.43%(4/35), and tumor types also appeared diversification including the hemangioma, myelocytomas, lymphatic sarcoma, fibrosarcoma and adenocarcinoma.Therefore, the early application of thiamphenicol can lead to immunosuppression, promote the tumorigenic effect and diversify the tumor types of ALV-J.The second animal experiment lasted for 42 d. 45 SPF chickens at 1 day of age were randomly assigned into three groups of 15 each. The experimental group was respectively given with ribavirin(100mg/L) and moroxydine(100mg/L) lasting for five days, three times with 5 days of the internal, and the last group was negative control. A comprehensive evaluation about ribavirin and moroxydine on the influence of ALV- J congenital infection was carried out by cloaca detoxification and viremia of ALV-J, vaccine immunization level of ND/H9, the immune organ index and body weight. Although ribavirin had the inhibitory effect of ALV-J propagation and increase the ND/H9 antibody and weight body compared with the virus group, it had no significant influence on viremia elimination and occurrence of ALV-J antibody. In addition, moroxydine didn’t show anti-ALV-J activity either in vivo or in vitro.In conclusion, the astragalan can be an additional method for the ALV-J eradication in chinken in the future. However, the clinical application of thiamphenicol may contribute to the development of avian leukemia J.