Susceptibility of Various Parental Lines of Commercial White Leghorn Layers to Infection with a Naturally Occurring Recombinant Avian Leukosis Virus Containing Subgroup B Envelope and Subgroup J Long Terminal Repeat (original) (raw)
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Turkish Journal of Veterinary and Animal Sciences, 2006
The aim of this study was to investigate the presence of antibodies to ALV-J in broilers and broiler breeders. For this, 5 broiler units and 1 broiler breeding unit in the Marmara region were visited. Seventy 4-6-week-old chicks from the broiler units, consisting of 14 chicks from each broiler unit, were selected. Seventeen chickens from the broiler breeding unit were also selected. The chicks from the broiler units were necropsied and all internal organs were checked for the presence of tumors. Blood sera collected from all animals were analyzed for the presence of antibodies to avian leukosis virus subgroup-J (ALV-J) by a commercial ELISA (IDEXX). Growth retardation, depression, diarrhea and respiratory disorders were seen in chicks from the broiler units. No tumors were observed in the internal organs. However, pseudomembranes on the liver of 3 chicks and Gumboro-like lesions in the bursa of Fabricius in 5 chicks were seen. No antibodies to ALV-J were detected in any of the broiler chicks' sera. However, antibodies to ALV-J were detected in 13 (76%) of the17 broiler breeders, which indicates the necessity to apply eradication programs for ALV-J in breeding flocks in Turkey.
Avian Diseases, 2004
In Experiment 1, a monoclonal antibody against the envelope glycoprotein (gp85) of subgroup J avian leukosis virus (ALV-J) was used to study the distribution of ALV-J in various tissues of White Leghorn chickens inoculated as embryos with the strain ADOL-Hc1 of ALV-J. At 2 and 6 wk of age, various tissues from infected and control uninfected chickens were tested for the presence of ALV-J gp85 by immunohistochemistry. In Experiment 2, using the methyl green-pyronine (MGP) stain, sections of bursa of Fabricius (BF) from chickens of line 15I 5 3 7 1 , inoculated with ALV-J or Rous-associated virus-1 (RAV-1), a subgroup A ALV, at hatch were examined for transformation of bursal follicles at 4 and 10 wk of age. In Experiment 1, specific staining indicative of the presence of ALV-J gp85 was noted at both 2 and 6 wk of age in the adrenal gland, bursa, gonads, heart, kidney, liver, bone marrow, nerve, pancreas, proventriculus, spleen, and thymus. In Experiment 2, by 10 wk of age, transformed bursal follicles were detected in MGP-stained sections of BF in only one of five (20%) chickens inoculated with ALV-J at hatch, compared with five of five (100%) chickens inoculated with RAV-1. The data demonstrate distribution of ALV-J gp85 in various tissues of White Leghorn chickens experimentally inoculated as embryos with the virus. The data also confirm our previous observation that ALV-J is capable of inducing transformation of bursal follicles, albeit the incidence is less frequent than that induced by subgroup A ALV. C Corresponding author.
Avian Diseases, 2008
Primary chicken embryo fibroblasts (CEF) from special specific pathogen-free chicken lines are used for detection of contamination of adult or embryonic tissues, meconium, or tissue culture fluids with avian leukosis viruses (ALV). The suitability and efficiency of such tests depend on the susceptibility of CEF to the various subgroups of exogenous as well as endogenous ALV. The ideal CEF for such tests should be not only susceptible to all retroviruses, but also free of endogenous viruses so that such tests are immune to any interference that may occur between the endogenous and the tested (exogenous) viruses. CEF and/or chickens free of endogenous viruses are also desirable for gene transfer studies using retroviral vectors, such as RNA interference (RNAi) experiments and transgenic work. The absence of ev genes in CEF or chickens can empower clean detection of successful RNAi construct delivery or gene transfer. CEF free of ev genes are also essential reagents routinely used in growing and detecting unknown retroviruses in varied viral assays. This report documents the development of a new line of chickens, 0.TVB*S1, that is free of endogenous viruses and susceptible to all subgroups of ALV identified in chickens.
Hemangioma and Myelocytomas Induced by Avian Leukosis Virus Subgroup J in Commercial Layer Flocks
2009
An outbreak of hemangiomas and myelocytomas in 26 to 29-week-old egg-type chickens was observed in eastern China during late 2007. Mortality of the five flocks is 5~10%. Hemangiomas of various sizes were seen scattered over the trunk, claws, wings, and head. At necropsy, hemangiomas appeared in the pancreases, ovarian follicles and livers. In addition, numerous similar nodular lesions and resembling tumors were seen in the same tissues. Eighty-six serum samples from the five flocks were tested for the presence of ALV-J, ALV-A/B and REV antibodies by enzyme-linked immunosorbent assay (ELISA) technique. The overall seroprevalence of ALV-J antibodies was 61.63% (53/86), while ALV-A/B and REV antibodies were negative. Histologically, hemangiomas were typically cavernous hemangiomas with sponge-like architectures and myeloblastic infiltration, in which large multifocal islands of myeloblasts or myelocytes were observed. Immunohistochemistry with ALV-J and REV monoclonal antibodies revealed a diffuse presence of ALV-J antigen in hemangiomas, myelocytomas, bone marrow, liver, and other internal organs, especially in endothelial cells of small vessels, while there was no REV antigen. PCR analyses revealed the presence of ALV-J proviral sequences were more closely related to HPRS-103 than the to other Chinese field strains and ADOL-7501. No evidence of Marek's disease or lymphoid leukosis was found. The studies found that hemangiomas and myelocytomas appeared in same tissue at same time in layer chickens were induced by avian leukosis virus subgroup J (ALV-J).
The impact of endogenous Avian Leukosis Viruses (ALVE) on production traits in elite layer lines
Poultry Science, 2021
Avian Leukosis Virus subgroup E (ALVE) integrations are endogenous retroviral elements found in the chicken genome. The presence of ALVE has been reported to have negative impacts on multiple traits, including egg production and body weight. The recent development of rapid, inexpensive and specific ALVE detection methods has facilitated their characterization in elite commercial egg production lines across multiple generations. The presence of 20 ALVE was examined in 8 elite lines, from 3 different breeds. Seventeen of these ALVE (85%) were informative and found to be segregating in at least one of the lines. To test for an association between specific ALVE inserts and traits, a large genotype by phenotype study was undertaken. Genotypes were obtained for 500 to 1500 males per line, and the phenotypes used were siredaughter averages. Phenotype data were analyzed by line with a linear model that included the effects of generation, ALVE genotype and their interaction. If genotype effect was significant, the number of ALVE copies was fitted as a regression to estimate additive ALVE gene substitution effect. Significant associations between the presence of specific ALVE inserts and 18 commercially relevant performance and egg quality traits, including egg production, egg weight and albumen height, were observed. When an ALVE was segregating in more than one line, these associations did not always have the same impact (negative, positive or none) in each line. It is hypothesized that the presence of ALVE in the chicken genome may influence production traits by 3 mechanisms: viral protein production may modulate the immune system and impact overall production performance (virus effect); insertional mutagenesis caused by viral integration may cause direct gene alterations or affect gene regulation (gene effect); or the integration site may be within or adjacent to a quantitative trait region which impacts a performance trait (linkage disequilibrium, marker effect).
Avian Pathology, 1999
Avian leukosis retroviruses (ALV) cause lymphomas and other cancers in chickens. Previous studies have used enzyme-linked immunosorbent assays (ELISA) and indirect immuno¯uorescence assays (IFA) to detect ALV p27 group-speci® c antigens (GSA) in commercial chicken eggs. In the poultry industry eradication programme against exogenous ALV, ELISA assays are used to identify chickens infected with the virus. The inability of ELISA and IFA assays to discriminate between ALV GSA of endogenous or exogenous origin, and actual virus, have limited rigorous assessments of viral transmission dynamics. Here, we report the use of a newly developed reverse transcriptase-polymerase chain reaction (RT-PCR) assay, with direct sequencing of the RT-PCR product, to show endogenous and exogenous ALV in albumen from unfertilized chicken eggs. We found that 95% of 20 eggs from ALV-exposed commercial chickens and 14.2% of 240 egg samples from 20 randomly chosen New Orleans retail stores were ALV-positive by RT-PCR. In comparison, only 2.5% of the same egg samples from the retail stores were positive by ELISA. Corresponding direct sequencing of randomly chosen RT-PCR products showed that four of six egg samples contained endogenous ALV, while two of the six samples were positive for exogenous subgroup A ALV. The ® nding of endogenous subgroup E ALV in unfertilized chicken eggs emphasizes that the transmission of endogenous ALV is common and should be considered in the implementation of ALV eradication programmes by the poultry industry.
2016
The present study was designed with a view to identify the Avian Leukosis Virus (ALV) by direct Enzyme Linked Immunosorbent Assay (ELISA) as well as to know the prevalence of ALV in different age groups of layer birds at Dinajpur district of Bangladesh. The birds were categorized into three groups, namely group A (brooder) included bird aged 13 days, group B (grower) included bird aged 16 weeks and lastly group C (layer) included bird aged 32 weeks. In this study a total of 92 cloacal swab samples were examined and 13 positive cases of ALV was found among which 5, 4 and 4 positive samples were in grower, brooding and layer chickens respectively. This study showed that ALV positive cases were 14.13% in layer birds whereas 14.5% positive cases in Sonali chicken and 13.3% in case of Hy-Line brown chicken. The inoculation of cloacal swab was done into five 10 days old embryonated chicken eggs through yolk sac route. After 5 days of inoculation death of the all embryos with haemorrhage was observed indicating the prevalence of Avian Leukosis Virus in the study area of Bangladesh. Since Avian Leukosis Virus transmitted both horizontally and vertically therefore measures to prevent spread are more demanding.
Folia biologica, 2003
We have studied the pathogenic changes in Khaki Campbell ducks injected in mid embryogenesis with ALV subgroup C virus td daPR-C derived from a molecular clone. The employed duck flock was shown to be highly genetically homogeneous and was controlled for the absence of current infections. Clear symptoms of wasting disease, which appeared since one week post hatching, represented the early consequence of the virus infection. They were manifested by decreased body weight, including clear involution of thymic tissue and pronounced anaemia. Microscopically, thymuses of infected animals displayed lymphatic depletion, clearly visible in the lobular cortex. Similarly, in the bursa Fabricii follicles, a marked reduction of the cortical layer and a decrease in folicullar centres was revealed. A decrease in the antibody response correlated with bursa Fabricii atrophy. The clear signs of anaemia were confirmed by haematological measurements, red blood cell count, haematocrit value and haemoglo...