| Summary: | 碩士 === 國立臺灣大學 === 獸醫學研究所 === 90 === Subgroup J avian leukosis virus (ALV-J) has become more and more important because its rapid horizontal spread, and it causes body weight suppression in commercial broilers. Since Taiwan broiler breeders are imported from other countries, we would like to know the situation of ALV-J infection in Taiwan broilers as the breeding companies claim that they have controlled the ALV-J infection in their breeders. Furthermore, there was no information on ALV-J infection in native chickens in Taiwan. Thus, the objectives of this study were to investigate the situation of ALV-J infection in broilers and native chickens in Taiwan. Because commercial ELISA kit had false positive reaction, virus isolation and RT-PCR were used for identification of ALV-J infection. We had totally investigated 8 commercial broiler flocks from a slaughter house, and 5 of them were infected with ALV-J (62.5%). We had investigated 4 native chicken flocks and 1 native chicken breeder flocks, and only the native chicken breeder showed ALV-J infection. Immunotolerant infection was suspected in the native breeder chickens since they showed viremia and lack of antibody (V+A-). The sequences of the gp85 gene of ALV-J isolates from breeders, broilers and native chickens were 94-100% identity among them. Phylogenetic trees showed that Taiwan isolates fell into two lineages. And it indicated those isolates had no relation to poultry flocks and breeders. Furthermore, Phylogenetic trees showed isolates could be grouped together by time they isolated, and virus variation could be saw during past 3 years (2000-2002). Thought commercial application of the eradication program over several years has resulted in a marked reduction in the prevalence of ALV-J in overseas breeding company, according to our research, Taiwan is still highly contaminated by ALV-J. So we have to control ALV-J infection strictly in Taiwan.
|
|---|
