Routes and prevalence of shedding of psittacine beak and feather disease virus.

Psittacine beak and feather disease (PBFD) virus was recovered from the feces and crop washings from various species of psittacine birds diagnosed with PBFD. High concentrations of the virus also could be demonstrated in feather dust collection from a room where 22 birds with active cases of PBFD were being housed. The virions recovered from the feces, crop, and feather dust were confirmed to be PBFD virus by ultrastructural, physical, or antigenic characteristics. Virus recovered from the feather dust and feces hemagglutinated cockatoo erythrocytes. The specificity of the agglutination was confirmed by hemagglutination inhibition, using rabbit antibodies against PBFD virus. During the test period, 26% (8 of 31) of the birds screened were found to be excreting PBFD virus in their feces, and 21% (3 of 14) of crop washings were positive for PBFD virus. Some birds in the sample group had active cases of diarrhea, whereas others had normal-appearing feces. Diarrhea was found to be the only significant indicator of whether a bird was likely to be excreting virus from the digestive tract. These findings suggest that exposure of susceptible birds to PBFD virus may occur from contact with contaminated feather dust, feces, or crop secretions. Viral particles that were morphologically similar to parvovirus (20- to 24 nm-icosahedral nonenveloped virions) also were recovered from feces of some of the birds.     

Severe leukopenia and liver necrosis in young African grey parrots (Psittacus erithacus erithacus) infected with psittacine circovirus

This paper describes the signs, clinical pathology, and postmortem findings in 14 young African grey parrots (Psittacus erithacus erithacus) that were naturally infected with psittacine beak and feather disease (PBFD) virus (psittacine circovirus). All but two of the parrots had severe leukopenia at clinical presentation. Two other parrots also had severe anemia. All birds died within 3 wk after presentation. Postmortem examination documented liver necrosis in 11 of 14 birds and secondary bacterial or fungal infections in 9 of 14 birds. Tests for Chlamydia psittaci, polyomavirus, and Salmonella sp. were negative. PBFD viral infection could be demonstrated in all birds by polymerase chain reaction. Supporting evidence of PBFD viral infection was gathered by histologic examination of the bursa of Fabricius, electron microscopy, and DNA in situ hybridization. Electron microscopic examination of both the bursa of Fabricius and liver revealed virus particles resembling circovirus. DNA in situ hybridization of six liver tissue samples confirmed the presence of PBFD virus and excluded the presence of avian polyomavirus. Our findings suggest that a specific presentation of peracute PBFD viral infection, characterized by severe leukopenia, anemia, or pancytopenia and liver necrosis in the absence of feather and beak abnormalities, may occur in young African grey parrots.     

Electron microscopical observations of psittacine beak and feather disease in an Umbrella cockatoo (Cacatua alba).

Psittacine beak and feather disease (PBFD) was diagnosed in an umbrella cockatoo (Cacatua alba) with severe feather dystrophy and loss. Electron microscopically, the intranuclear and intracytoplasmic inclusion bodies observed by light microscopy were composed of viral particles forming paracrystalline arrays, whorls, semicircles or concentric circles. Recovered viral particles from the skin and feather follicle tracts were icosahedral and 15 to 20 nm in diameter.     

Hemagglutination by psittacine beak and feather disease virus and use of hemagglutination inhibition for detection of antibodies against the virus.

Conditions for psittacine beak and feather disease (PBFD) virus hemagglutination and hemagglutination-inhibition (HI) test reactions are defined. The PBFD virus was found to hemagglutinate cockatoo and some guinea pig erythrocytes. The HI test was used to assay serum antibody titer in birds with active PBFD virus infections and in others that had been exposed to diseased birds. On the basis of HI antibody titers in psittacine birds that had been exposed to PBFD virus, but remained clinically normal, we suggest that some birds exposed to the virus are able to mount an effective immune response. Birds with active PBFD virus infections had lower antibody values than did birds that had been exposed to the virus, but remained clinically normal. On the basis of these findings, the ability to develop a suitable HI antibody response may be crucial in determining the disease status of susceptible birds exposed to the PBFD virus. If HI antibodies are found to have neutralizing activity, then the fact that a high HI titer was induced in birds inoculated with purified PBFD virus might suggest that an immunization program would be effective in preventing PBFD virus infections.     

Extracutaneous viral inclusions in psittacine beak and feather disease

Thirty-five birds that died with naturally acquired psittacine beak and feather disease (PBFD) were necropsied to identify extracutaneous viral inclusions. Inclusions were found in various tissue sections from 34 of 35 birds. By immunoperoxidase staining, intranuclear and intracytoplasmic inclusion bodies were shown to contain PBFD viral antigen. Inclusion-bearing lesions were widely disseminated but often closely associated with the alimentary tract. Lesions within the palate, esophagus, crop, intestine, bursa of Fabricius, and liver probably serve as sources for viral shedding into the feces.     

Laboratory diagnosis of psittacine beak and feather disease by haemagglutination and haemagglutination inhibition

SUMMARY Simple and sensitive haemagglutination and haemagglutination Inhibition assays were developed for psittacine beak and feather disease (PBFD) virus and serum antibody, respectively. The assays were used in the examination of samples from 73 birds clinically affected with PBFD. High antigen titres (log₂ 9 to log₂ 12) were detected In feathers, faeces and cloacal contents of PBFD-affected birds. Antigen was not detected In either faecal or feather samples from 20 normal galahs (Eolophus roselcapillus) and 9 normal sulphur crested cockatoos (Cacatua galerita). After kaolin treatment and haemadsorption of serum, haemagglutination inhibition (HI) antibody titres could not be detected in serum from 42 PBFD-affected birds, whereas serum HI titres from 64 normal psittacine birds ranged from less than log₂ 1 to log₂ 8. Serum and yolk HI antibody responses of 6 PBFD virus-inoculated layer hens were measured. Pre-inoculation chicken sera contained high concentrations of non-specific haemagglutination inhibitors (not detected in chloroform-extracted yolk), which were removed by kaolin treatment and haemadsorption.     

福建省部分地区鹦鹉喙羽病的分子流行病学调查及其病原Cap蛋白抗原表位预测

为了解2017—2018年鹦鹉喙羽病在福建省某些地区鹦鹉中的流行情况,收集了福建省部分地区298份鹦鹉粪便样品,采用PCR方法进行粪便样品检测,对其中鹦鹉喙羽病病毒检测呈阳性的5个地区的样品进行衣壳蛋白(Cap)基因测序后比较其同源性,绘制系统进化树,分析氨基酸序列,并通过生物信息学及序列分析软件预测Cap蛋白二级结构及B细胞抗原表位。结果显示:鹦鹉喙羽病病毒的平均阳性率为41.28%,福州市某动物救助站和福州动物园的阳性率较高,分别为65.17%和64.29%,其次为三明动物园、福州市花鸟市场和福州市某鹦鹉繁殖基地,南平动物园的阳性率最低;所测5个毒株Cap基因与GenBank中新西兰株(AY518913)亲缘关系较近;Cap蛋白有丰富的二级结构和多处抗原指数较高的区域,具有潜在的B细胞抗原表位,位于5~27、110~127和141~153位氨基酸残基或其附近。研究结果对防控鹦鹉喙羽病,保障鹦鹉健康养殖有重要参考意义。     

Antibody response to and maternal immunity from an experimental psittacine beak and feather disease vaccine.

Adult umbrella cockatoos, Moluccan cockatoos, African grey parrots, and a yellow-headed Amazon parrot were inoculated IM or SC with beta-propiolactone-treated psittacine beak and feather disease (PBFD) virus. Thirty- to 45-day-old African grey parrot, umbrella cockatoo, and sulphur-crested cockatoo chicks also were vaccinated with the same inoculum. The hemagglutination inhibition (HI) and agar-gel diffusion tests were used to assay for post-vaccination development of anti-PBFD virus antibodies. All adult vaccinates seroconverted and had increases in HI and precipitating antibodies. The vaccinated chicks had increased concentrations of HI antibodies, but precipitating antibodies could not be detected. To demonstrate that chicks from vaccinated hens are protected from PBFD virus challenge, 3 African grey parrot chicks and 2 umbrella cockatoo chicks from vaccinated hens and 1 African grey parrot chick and 1 umbrella cockatoo chick from nonvaccinated hens were exposed to purified PBFD virus. Chicks from the vaccinated hens remained clinically normal during the 50-day test period. Chicks from the nonvaccinated hens developed clinical and histologic lesions of PBFD. Infected tissues from these birds were confirmed to contain viral antigen, using immunohistochemical staining techniques. The PBFD virus was recovered from the affected birds. These findings indicate that adult and 30- to 45-day-old psittacine birds will seroconvert following vaccination with beta-propiolactone-treated PBFD virus. Also, hens inoculated with beta-propiolactone-treated PBFD virus produce chicks that are, at least temporarily, resistant to virus challenge.     

Production and characterization of monoclonal antibodies to psittacine beak and feather disease virus.

Monoclonal antibodies specific for the virus that causes psittacine beak and feather disease (PBFD) were produced by fusing spleen cells from mice immunized with purified concentrated PBFD virus with mouse myeloma cell line Sp2/0. The resulting hybridomas were tested for reactivity against whole purified virus by an enzyme-linked immunosorbent assay (ELISA) system. Four clones, designated 15H8, 8E3, 11G12, and 2C3, were subcloned by limiting dilution. Isotyping indicated that clone 15H8 was secreting IgG, whereas the remaining clones secreted IgM. The secreted immunoglobulins were characterized by reactivity against purified PBFD virus using immunoblotting procedures, by immunohistochemical staining of virus-induced lesions in infected tissues, and by inhibition of PBFD virus agglutination of cockatoo erythrocytes. Antibodies secreted by clones 15H8 and 8E3 had the strongest activity against purified whole virus. Only immunoglobulin secreted by the clone 15H8 could be used to detect viral antigen in infected tissues. None of the monoclonal antibodies had hemagglutination-inhibition activity.     

The sensitivities of various erythrocytes in a haemagglutination assay for the detection of psittacine beak and feather disease virus

The erythrocytes of various species were tested in psittacine beak and feather disease (PBFD) virus haemagglutination (HA) and haemagglutination inhibition assays to determine which are suitable for use in these assays. HA activity was observed for erythrocytes of the salmon-crested cockatoo, the sulphur-crested cockatoo, the umbrella cockatoo, the goffin's cockatoo and the cockatiel, with differences amongst individuals within species, but not for erythrocytes of humans, the pig, the guinea pig, the chicken, the goose, the rose-ringed parakeet or the budgerigar. Anti-PBFD virus rabbit sera inhibited the virus-induced agglutination of erythrocytes, confirming the specificity of HA activity. This suggests that selection of suitable psittacine species as well as suitable individuals within a species is necessary when obtaining erythrocytes for the PBFD virus HA assay.     

Vaccination and challenge studies with psittacine beak and feather disease virus

SUMMARY: Psittacine beak and feather disease virus (PBFDV) was administered to adult galahs ( Eolophusroselcapillus ) by mouth or by intramuscular injection. Concentration of PBFDV antibodies in serum and excretion of PBFDV were monitored by haemagglutlnation inhibition (HI) and haemagglutination (HA) respectively. After oral administration, 17 of 18 galahs remained clinically normal and a small rise in antibody titre was detected in 3 of 18 birds. After intramuscular administration, antibody was detected in all birds. PBFDV was not detected in the feather dander of birds in either group. One bird developed diarrhoea and high faecal HA titres within 4 days of oral administration and then died. Adult and nestling cockatoos were vaccinated with an experimental inactivated double-oil emulsion vaccine. PBFDV antibody responses are comparable to those induced by a primary-oil emulsion vaccination regimen using Freund's adjuvants. Both vaccines protected nestlings. Three sibling wild-caught sulphur-crested cockatoos were vaccinated but died of PBFD before experimental challenge despite antibody responses in all birds. Unvaccinated control chicks developed acute PBFD within 4 weeks of challenge, probably from PBFDV-induced hepatitis since high concentrations of PBFDV were detected in their livers.     

A universal polymerase chain reaction for the detection of psittacine beak and feather disease virus.

A universal PCR assay was designed that consistently detected psittacine beak and feather disease virus (BFDV) in psittacine birds affected with psittacine beak and feather disease (PBFD) from different geographic regions across Australia. Primers within open reading frame 1 (ORF1) of the BFDV genome consistently amplified a 717 bp product from blood and/or feathers of 32 birds with PBFD lesions. The PCR did not amplify a product from the feathers or blood from 7 clinically normal psittacine birds. Primers based on regions outside of ORF1 did not consistently produce a PCR product, suggesting there was some genomic variation outside ORF1. The amplified ORF1 PCR products of 10 BFDV isolates, from different psittacine species and from various regions around Australia, were cloned and comparative DNA sequence analysis demonstrated 88-99% of the ORF1 fragments. The derived amino acid sequences of the amplified ORF1 fragments demonstrated similar identity between all 10 isolates. Within ORF1, there was complete conservation of the putative nucleotide binding site and marked conservation of 2 other motifs previously identified as essential components of the replication-associated proteins of other circoviruses and geminiviruses.     

Psittacine beak and feather disease: a first survey of the distribution of beak and feather disease virus inside the population of captive psittacine birds in Germany

Psittacine beak and feather disease (PBFD) is the most common viral disease of wild and captive psittacine birds. Here, we designed the first survey to investigate the existence of subclinical infections and the distribution of the causative agent named beak and feather disease virus (BFDV) inside the population of captive psittacine birds in Germany. DNA was isolated from feathers of 146 symptom-free birds from 19 different genera (all psittaformes) taken from 32 independent breeders from all over Germany. The presence of BFDV was analysed by performing polymerase chain reaction assays. Fifty-eight (39.2%) samples were found to be positive for BFDV. As expected, there was no significant predominance of one sex to be infected with BFDV.     

Psittacine beak and feather disease virus in budgerigars and ring-neck parakeets in South Africa

Psittacine beak and feather disease (PBFD) is a common disease of the psittacine species and is caused by the psittacine beak and feather disease virus (PBFDV). In this study the occurrence of the disease in ring-neck parakeets and budgerigars in South Africa suffering from feathering problems, using polymerase chain reaction as a diagnostic test was investigated. The genetic variation between viral isolates was also studied. Results indicate that PBFDV can be attributed to being the cause of feathering problems in some of the ring-neck parakeets and budgerigars in South Africa. Genetic variation of isolates occurs between species and individuals. A cheap and easy to use method of blood sample collection on filter paper for diagnostic purposes was also evaluated. It proved to be less stressful to the birds and did not inhibit further processes.     

Detection of pigeon circovirus by polymerase chain reaction

Pigeon circovirus was identified by polymerase chain reaction (PCR) in young pigeons belonging to 12 different lofts. Viral DNA was extracted from formalin-fed, paraffin-imbedded tissues containing primarily bursa and occasionally liver and spleen with a commercial kit. PCR primers were selected from a published sequence for columbid circovirus and evaluated in a PCR assay. The histopathologic examination of various tissues revealed basophilic globular intracytoplasmic inclusions in the mononuclear cells of the bursa of Fabricius and occasionally in the spleen characteristic for a circovirus. Transmission electron microscopy of a few bursas of Fabricius revealed virus particles measuring 18-21 nm. All the samples were negative by PCR for psittacine beak and feather disease (PBFD) virus and chicken infectious anemia virus. The primers for both pigeon circovirus and PBFD virus did not react in PCR with the chicken anemia virus DNA. Most of the circovirus-infected pigeons had concurrent infections of Escherichia coli, Salmonella, Pasteurella, Aspergillus, candidiasis, nematodiasis, or capillariasis.     

Beak and feather disease virus haemagglutinating activity using erythrocytes from African Grey parrots and Brown-headed parrots

Psittacine beak and feather disease (PBFD) is a common viral disease of wild and captive psittacine birds characterized by symmetric feather loss and beak deformities. The causative agent, beak and feather disease virus (BFDV), is a small, circular single-stranded DNA virus that belongs to the genus Circovirus. BFDV can be detected by PCR or the use of haemagglutination (HA) and haemagglutination inhibition (HI) assays that detect antigen and antibodies respectively. Erythrocytes from a limited number of psittacine species of Australian origin can be used in these tests. In South Africa, the high cost of these birds makes them difficult to obtain for experimental purposes. Investigation into the use of erythrocytes from African Grey parrots and Brown-headed parrots yielded positive results showing the haemagglutinating activity of their erythrocytes with purified BFDV obtained from confirmed clinical cases of the disease. The HA activity was further confirmed by the demonstration of HI using BFDV antiserum from three different African Grey parrots previously exposed to the virus and not showing clinical signs of the disease.     

蒸煮酶解羽毛粉的营养价值及其在肉鸭上的能量和氨基酸利用率评定

本试验旨在研究采用真代谢能(TME)法评定3种蒸煮酶解羽毛粉对于肉鸭的能量和氨基酸营养价值,为合理开发和利用羽毛粉蛋白质资源提供基础数据。3种羽毛粉(Ⅰ~Ⅲ)分别为42日龄樱桃谷肉鸭羽毛粉、550日龄罗曼蛋鸡羽毛粉和100日龄三黄肉鸡羽毛粉。试验选取20只7周龄樱桃谷肉鸭,随机分为4个处理,每个处理5个重复,每个重复1只肉鸭,单笼饲养。处理1(T1)为测定羽毛粉Ⅰ,处理2(T2)为测定羽毛粉Ⅱ,处理3(T3)为测定羽毛粉Ⅲ,处理4(T4)为饥饿处理。试验期为7 d。结果表明:1)以干物质(DM)为基础,羽毛粉Ⅰ、Ⅱ、Ⅲ的总能(GE)分别为21.31、21.02和20.18 MJ/kg,表观代谢能(AME)分别为13.71、12.29和12.10 k J/kg,TM E分别为14.83、13.42和13.22 M J/kg。2)以DM为基础,羽毛粉Ⅰ、Ⅱ、Ⅲ的粗蛋白质(CP)含量分别为91.05%、87.31%和91.06%;羽毛粉Ⅰ、Ⅱ、Ⅲ的总氨基酸(TAA)含量都在80%以上,但不同羽毛粉的氨基酸含量差异较大。3)羽毛粉Ⅰ、Ⅱ、Ⅲ的TAA表观可代谢率分别为81.51%、73.07%和76.85%,TAA真可代谢率分别为85.09%、76.89%和80.43%。3种羽毛粉的表观可利用氨基酸和真可利用氨基酸含量也存在显著差异(P0.05)。由此可见,利用TM E法测定毛粉能量与氨基酸的营养价值,发现3种羽毛粉的代谢能(M E)、表观可利用氨基酸和真可利用氨基酸存在明显差异。羽毛粉Ⅰ的GE、ME、CP及TAA代谢率均高于羽毛粉Ⅱ和羽毛粉Ⅲ。     

Growth performance, carcass characteristics, nutrient digestibility and fecal odorous compounds in growing-finishing pigs fed diets containing hydrolyzed feather meal

This study was designed to determine the effects of hydrolyzed feather meal inclusion on growth performance, carcass characteristics, nutrient digestibility and fecal odorous compounds in modern lean growth genotype pigs. Two hundred forty pigs (BW = 23.2 +/- 1.3 kg) were allotted based on BW and sex to a 2 x 6 factorial arrangement of treatments (four pens per treatment; five pigs per pen) in a randomized complete block design. Factors consisted of 1) sex (barrows or gilts) and 2) dietary treatment (0, 2, 4, 6, 8, or 10% hydrolyzed feather meal). Diets were formulated to contain 1.00, 0.90, 0.75, or 0.60% apparent ileal digestible lysine for phases 1 to 4, respectively, with other amino acids provided at an ideal ratio. Available P and ME were kept constant within each phase. No significant interactions between feather meal inclusion and sex were observed for growth performance (P > 0.15). Body weight gain was reduced (P < 0.05) for pigs fed 10% feather meal compared to pigs fed 0, 4, or 8% feather meal. Feed intake of pigs fed 10% feather meal was reduced (P < 0.05) compared to pigs fed 0 or 4% feather meal. Ultrasound backfat measurements tended (P = 0.12) to increase with increasing levels of feather meal. Daily lean gain was less (P < 0.05) in pigs fed 10% feather meal than in pigs fed either 0, 2, 4, or 8% feather meal. Digestibility of N measured on wk 9 decreased quadratically (P < 0.001) with increasing levels of feather meal. Phosphorus digestibility increased in a linear fashion (P < 0.02), however, the improvement in P digestibility with increasing levels of feather meal was more pronounced in barrows compared to gilts (interaction, P < 0.05). Fecal samples obtained from pigs fed 0, 4, or 8% feather meal were analyzed for odorous compounds. Concentrations of butanoic, pentanoic, and 3-methylbutanoic acid were greater (P < 0.05) and concentrations of 3-methylphenol, 4-methylphenol, indole, and decane were less (P < 0.05) in feces from pigs fed feather meal. These results suggest that feather meal can be included in diets for growing-finishing pigs at a rate of 8%. Excretion of N in feces increased but P excretion decreased with increasing levels of feather meal. Odorous compounds in feces can be affected by the inclusion of hydrolyzed feather meal, but the exact impact of these changes on odor perception remains to be elucidated.     

家鸡羽色性状遗传调控机制研究进展

自然界中鸟类呈现出丰富的羽毛颜色,羽色性状在躲避天敌、捕食、求偶及抵御紫外线等方面都具有重要作用。对鸡羽毛颜色性状的研究有助于加强品种区分、识别,在育种工作中建立品种间的显著标识和保障同一品种外观整齐尤为重要。羽毛颜色是禽类表型遗传研究的重要组成部分,它主要由黑色素和类胡萝卜素所决定。目前鸡羽毛颜色性状遗传调控机制的研究大多集中在黑色素相关通路,其中,Wnt、KIT/KITL和EDN3/EDNRB等信号通路对黑素细胞的生长发育、迁移和分化具有重要的调控作用,α-MSH/ASIP-MC1R信号通路负责调控黑色素的合成。已有研究显示,通过全基因组范围内的遗传变异检测技术挖掘与羽色性状相关的基因和变异位点,可以揭示黑羽、麻羽、显性白羽、隐形白羽、常染色体白化、银羽、性连锁不完全白化、深棕色羽、淡紫色羽(灰羽)、非依赖酪氨酸酶的隐性白羽、斑点羽和性连锁横斑羽(芦花羽)等多种羽色性状的遗传调控机制。此外,以图灵模型为理论基础可以解释复杂羽色图案的形成机制。作者通过总结黑色素相关调控通路与图灵模型对家鸡羽毛颜色性状的遗传调控机制,对近年来已经确定基因座的家鸡羽毛颜色性状相关研究展开综述,以期为鸡羽色分子机制研究以及在育种过程中开展鸡羽色性状标记辅助选择提供参考。     

High virus titer in feather pulp of chickens infected with subgroup J avian leukosis virus

Subgroup J avian leukosis viruses (ALVs), which are a recombinant virus between exogenous and endogenous ALVs, can spread by either vertical or horizontal transmission. Exogenous and endogenous ALVs can be detected in feather pulp. In this study, virus titers in feather pulp of chickens infected with subgroup J ALV were compared with those of plasma and cloacal swab. All of the broiler chickens inoculated with subgroup J ALV at 1 day old were positive for virus from feather pulp during the experimental period of between 2 wk and 8 wk of age. Virus titers in feather pulp of some broiler chickens infected with subgroup J ALV were very high, ranging from 10(7) to 10(8) infective units per 0.2 ml. Virus titers in feather pulp were usually the highest among the samples of plasma, cloacal swab, and feather pulp tested. In another experiment in which layer chickens were inoculated with subgroup J ALV at 1 day old, virus was detected in feather pulp from 2 wk until 18 wk of age, and virus persisted longer in feather pulp than in plasma. Almost all of the layer chickens tested were positive for virus by polymerase chain reaction (PCR) with DNA extracted from feather pulp samples at 2, 4, and 10 wk of age, and the PCR from feather pulp was more sensitive than virus isolation from plasma, cloacal swab, and feather pulp. All above results indicate that samples of feather pulp can be useful for virus isolation and PCR to confirm subgroup J ALV infection.