The Isolation And The Envelope Gene Sequence Analysis Of Avian Leukosis Virus Subgroup J In Anhui Province From 2012 To 2014

Subgroup J of avian leukosis was a kind of new Avian leukosis subgroups caused by Avian leukosis virus subgroup J(ALV-J),which was first isolated from broilers in the end of the 1980 s.The main clinical symptoms caused by ALV-J were immune and growth suppression.In recent years,the disease was widely popular in poultry industry in China and brought huge damage to the poultry industry.33 sick chickens from eight counties in Anhui Province between 2012 and 2014 were detected with the established method of ALV-J gp85 gene Polymerase Chain Reaction(PCR),the amount of ALV-J sick chickens was 16;598 anal swabs and 360 chicken egg white samples came from three farms in Anhui Province were detected with the method of ALV p27 antigen enzyme-linked immunosorbent assay(ELISA)test,the results showed that the ALV positive rates of anal swabs and chicken egg white samples were 33.4% and 10.58% respectively;the positive samples tested by PCR and ELISA would be inoculated to chicken embryo fibroblasts(CEF)to isolate ALV strains,the ALV virus strains were identified by the method of PCR,the results showed that 19 ALV-J strains were isolated successfully;the envelope protein gene gp85 and gp37 gene sequences were amplified by specific PCR method and be sequenced by biology company,on the basis,16 different ALV-J reference strains were selected from GenBank to conduct the gp85 and gp37 gene sequence homology alignment analysis,the gene evolutionary trees drawn,and the amino acid sequence alignment analysis with the isolated ALV-J strains,the gp85 gene sequence alignment results suggested that the homology between isolates and reference strains was 85.3%~98.1%,the homology between 19 ALV-J isolates was 91.9%~99.9%,the homology between the 19 isolates and the British prototype strain HPRS-103 was 87.6%~98.6%,with the combination results of gp85 gene genetic phylogenetic tree,showed that 18 isolates in the study were in a large evolutionary branching,which showed a close relationship to the prototype strain,the gp85 gene amino acid sequence alignment results showed different deletions and mutations arose in the location of 110~120,140~150 and 188~193 of the amino acid sequences,the amino acid sequence analysis of AH11-05 strain suggested that,there was a inserted sequence-GGGAACCTT-at the position between 579 bp and 589 bp,the gp37 gene sequence alignment results were consistent with the gp85 gene sequence alignment results on the whole,it was worth noting that the homology of gp37 gene sequence was relatively high,and there was no gene insertion or deletion.In the study,the prevalence of ALV-J in different type of chickens and different regions in Anhui Province in the recent three years was investigated,and 19 ALV-J strains were isolated successfully,which provided the fundamental for the further study of envelope protein gene mutation of ALV-J,and the preventive measures for the popularity of ALV-J in Anhui Province.