| Avian leukosis virus (ALV) designates a variety of transmissible benign and malignantneoplasms of chickens caused by members that belong to the family Retroviridae. It can causechickens’ subclinical infection and production performance decrease. In China, it was recentlydiscovered that ALV has spread to indigenous varieties of poultry; a serious threat has beenraised by the ALV to the safety of the local breed resources and great challenges have beenmade to conservation and breeding. At the present stage, the purification project for AL inChina is direct detection of the ALV p27antigen in albumen from hens and cloacal swabsfrom cocks in protospecies flocks, and aseptic anticoagulant bloods from both hens and cockswhich were detected ALVp27antigen positive in protospecies are collected for DF1cellinoculation for ALVp27antigen detection after a9-d culture; The ALV p27antigen-positivesamples are then washed out. Because the sources and test material handling differ, the levelof infection, which is determined through ALV p27antigen detection, is likely different; thus,purification efficiency is influenced.In this study, the infection status of BR chickens and the effect of ALV on BR chickenswere evaluated, which were through the detection of ALV infection rates and polymorphisms,the antigen localization of diseased tissue, the virus of the cell culture with both of the IFAand PCR detection. At the same time, the comparison between the ELISA detection results ofthe ALVp27antigen, from different samples and different treatment methods of the samesample in the core BR chickens, and ALV purification schemes commonly used in ourcountry presently was studied. The study showed that there were co-infection with ALV-J andALV-E in local strain BR chickens, and the co-infection of ALV-J and ALV-E could seriouslyimpact the production performance; the purification project for AL for cocks in China isinsufficient for full detection, and it is necessary to test the sperm both directly and after thesamples have been cultured in DF1cells. When the ALV p27antigen was directly detected,the albumen and cloacal swabs from hens are not sufficient as independent detection materials,and both sample types should be tested.1An Evaluation of the Infection Status in and Effect of Avian Leukosis Virus on LocalBR Chickens BR chickens, a famous variety native to China, have a long history; their eggs and meatare both delicious. Generally, the age at first egg of BR chickens is around one hundred days,and they have a stable production performance, with the egg number between130and180each year. However, they have been in increasingly serious danger.of the ALV in the recentyears. Therefore, in this study, the ALV infection status of local BR chickens was evaluated.In addition, the effect of ALV infection on production performance was explored. The p27antigen level was determined in391cloacal swabs from roosters and in1147eggs from henscollected from the protospecies;36.6%(143/391) and10.7%(118/1147), respectively, werepositive. In addition,10sick hens subjected to clinical observation were found to havepathological changes, including hemangioma and splenomegaly. Chicken embryo fibroblasts(CEFs) were inoculated with leukocytes from the10sick hens, and60%(6/10) and70%(7/10)were found to be positive for ALV-J and ALV-A, respectively. Additionally, positive signalsfor both ALV-J and ALV-A were prevalent in paraffin-embedded sections of the liver andovaries. Exogenous ALV-J (BR09J) and endogenous ALV-E (BR09E) were identified in thesame chicken by PCR. At day165, there was a marked but not significant difference in theegg weight and body weight of the hens between the ALV-positive individuals and thenegative individuals (p>0.05), whereas the egg numbers were significantly different (78.83vs.68.83, p<0.01). This report is the first on a natural case of co-infection with ALV-J andALV-E in Chinese native variety, and the co-infection of ALV-J and ALV-E was demonstratedto seriously reduce the production performance. Therefore, purification must be implementedto protect the local poultry varieties and prevent economic and diversity losses.2A study on testing materials for Avian Leucosis Purification in ChickensTo supplement the purification project for avian leucosis (AL) in China, ALV detectionmaterials were improved and compared. In this study,23hens and cocks were randomlyselected from infected chickens. Sperm, cloacal swabs, and aseptic anticoagulant bloodsamples were collected from each cock; albumen, cloacal swabs, and aseptic anticoagulantblood samples were collected from each hen. The ALV antigen was directly detected for eachsample. The ALV antigen was also detected after DF1cells were inoculated with the samples.For the cocks, through direct detection, the ALVp27antigen-positive rate in sperm was highest(47.8%), which was followed by aseptic anticoagulant bloods (39.1%) and cloacal swabs withthe lowest rate (30.4%), After the samples were cultured for9d in DF1, theALVp27antigen-positive rate in aseptic anticoagulant bloods was21.7%, which is higher thanfor both sperm (17.4%) and cloacal swabs (17.4%); however, the ALV positive samples from aseptic anticoagulant bloods did not fully contain all the ALV-positive sperm samples. For thehens, by direct detection, the ALV p27antigen positive rate in both albumens and cloacalswabs was (73.9%), and it was higher than that of aseptic anticoagulant bloods (43.5%), whilethe positive samples from both albumens and cloacal swabs were not the same. After thesamples were cultured for9d in DF1, the ALVp27antigen-positive rate was highest (13.0%) inthe aseptic anticoagulant bloods, which contained all the positive samples of albumen (4.3%)and cloacal swabs (0%). This study indicates that the purification project for AL for cocks inChina is insufficient for full detection, and it is necessary to test the sperm both directly andafter the samples have been cultured in DF1cells. When the ALV p27antigen was directlydetected, the albumen and cloacal swabs from hens are not sufficient as independent detectionmaterials, and both sample types should be tested. |
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