• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.166-171
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• 2002

The main objective of the present study is to estimate the crossbreeding parameters in respect to serum lysozyme level in broilers. The experiment involved a complete $4{\times}4$ diallel design using four synthetic broiler lines namely Coloured Synthetic Male Line (CSML), White Synthetic Male Line (WSML), Coloured Synthetic Female Line (CSFL) and Naked Neck Line (NNL). The lyophilised Micrococcus lysodeikticus suspension was used to detect the lysozyme level in the serum of birds. The data were analysed by least-squares method to find the effects of genetic and non-genetic factors using appropriate model. The crossbreeding parameters for this trait were estimated by complete diallel model assuming the effect of each synthetic line as fixed. The results indicated that additive and non-additive genetic variation attributed to minor genes at many loci is important for the genetic control of serum lysozyme level in chickens. Total non-additive components of variance also showed significant amount of heterosis in crossbred progenies, and therefore exploitation of non-additive component of variance is possible for improvement in serum lysozyme level in broilers. The overall results suggested that for commercial broiler production system, the selection for specialised line on the basis of serum lysozyme level and subsequent crossing of parent lines could enhance the immunocompetence status in relation to serum lysozyme level in crossbred chickens.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1447-1455
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• 2009

Two novel avian $\beta$-defensins (AvBDs) isolated from duck liver were characterized and their homologies with other AvBDs were analyzed. They were shown to be duck AvBD9 and AvBD10. The mRNA expression of the two genes was analyzed in 17 different tissues from 1-28-day-old ducks. AvBD9 was differentially expressed in the tissues, with especially high levels of expression in liver, kidney, crop, and trachea, whereas AvBD10 was only expressed in the liver and kidney of ducks at all the ages investigated. We produced and purified GST-tagged recombinant AvBD9 and AvBDI0 by expressing the two genes in Escherichia coli. Both recombinant proteins exhibited antimicrobial activity against several bacterial strains. The results revealed that both recombinant proteins retained their antimicrobial activities against Staphylococcus aureus under a range of different temperatures ($-70^{\circ}C-100^{\circ}C$) and pH values (pH 3-12).

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.207-214
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• 2005

The nonstructural protein 4 (NSP4) of rotavirus encoded by gene 10, plays an important role in rotavirus pathogenicity. In this study, NSP4 gene of avian rotavirus (AvRV-1, AvRV-2) was analyzed and expressed using baculovirus expression system. The sequence data indicated that the NSP4 gene of AvRV-1 and AvRV-2 were 727 bases in length, encoded one open reading frame of 169 amino acids beginning at base 41 and terminating at base 550, and had two glycosylation sites. Nucleotide sequences of NSP4 gene of AvRV-1 and AvRV-2 exhibited a high degree of homology ($88.1{\pm}7.6%$) with avian rotaviruses, namely Ty1, Ty3 and PO-13. Phylogenetic analysis showed that AvRV-1 and AvRV-2 belonged to genotype NSP4[E], which is widely found in group A avian rotaviruses. The baculovirus-expressed NSP4 migrated at 20-28 kDa and reacted with NSP4-specific antiserum by FA and Western blot. Furthermore, it was found to be a glycoprotein by using tunicamycin, which is a specific inhibitor of N-linked glycosylation.

• Journal of Veterinary Clinics
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• v.28 no.5
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• pp.530-532
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• 2011

A Eurasian jay (Garrulus glandarius) with lethargy, dyspnea, and poor physical condition was rescued and referred to the Animal Health Center, Seoul Zoo, Korea. The jay's eyelids were sealed with dark-colored hard scabs and it died the day after arrival. At necropsy, diphtheritic membranes on the tongue and oral mucosa were apparent, suggesting avian poxvirus infection based on the appearance of the oral diphtheritic lesions. PCR was conducted using a tissue sample to confirm the causative agent. The jay was diagnosed with an avian pox viral infection. This report describes the first case of a natural avian pox infection in a Eurasian jay in Korea.

• Korean Journal of Veterinary Research
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• v.64 no.2
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• pp.13.1-13.6
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• 2024

Avian influenza A viruses (IAVs) present significant threats to both animal and human health through their potential for cross-species transmission and global spread. Clade 2.3.4.4 H5Nx highly pathogenic avian IAVs initially emerged in East Asia between 2013 and 2014. Since then, they have spread to Europe, Africa, and America via migratory bird flyways. However, beyond viral transmission primarily facilitated by migratory birds, the potential involvement of other intermediate factors for virus transmission remains poorly investigated. This study aimed to investigate the role of wild rodents as intermediary hosts in the ecology of avian IAVs in Gyeonggi province, South Korea. By capturing and analyzing 189 wild rodents near poultry farms and migratory bird habitats in 2013 and 2014 and employing serological assays and virus isolation techniques, we found no evidence of IAV infection among these populations. Our results suggest that wild rodents may not significantly contribute to the transmission dynamics of IAVs within these regions.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.385-392
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• 1999

A total of 420 chicken sera from various regions were tested for the presence of antibodies to avian rotavirus using indirect immunofluorescence assay (IFA). In broiler farms, rotavirus antibodies were detected from 20 farms among 30 farms tested and the positive rates were above 50% in 9 farms. In parent stock farms, rotavirus antibodies were detected from 5 farms among 14 farms tested. From sera collected in 7 layer farms rotavirus antibodies were not detected.

• Korean Journal of Veterinary Research
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• v.53 no.4
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• pp.193-197
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• 2013

Avian influenza viruses (AIV) have been isolated from a wide range of domestic and wild birds. Wild birds, predominantly ducks, geese and gulls form the reservoir of AIV in nature. The viruses in wild bird populations are a potential source of widespread infections in poultry. Active surveillance for AIV infection provides information regarding AIV distribution, and global AIV surveillance can play a key role in the early recognition of highly pathogenic avian influenza (HPAI). Since 2003 in Korea, there have been four H5N1 HPAI outbreaks caused by clade 2.5, 2.2 and 2.3.2. Therefore, improvement of AIV surveillance strategy is required to detect HPAI viruses effectively. This article deals with the major events establishing the role of wild birds in the natural history of influenza in Korea. We highlighted the need for continuous surveillance in wild birds and characterization of these viruses to understand AIV epidemiology and host ecology in Korea.

• Proceedings of the Korea Contents Association Conference
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• 2009.05a
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• pp.1130-1135
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• 2009

Avian Influenza is an infectious desease of birds. The infection can cause a wide spectrum of symptoms in birds, ranging from mild illness to a rapidly fatal diseases which might bring a tremendous economic loss to poultry farms[1]. It can also give fatal diseases to human. Therefore it is important to surveil wildbirds that are primary transportation of avian influenza. This report showed a relationship between avian influenza and a habitat of wildbirds using system dynamics, and concluded with suggestion for surveilance.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2005.11a
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• pp.80-81
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• 2005

The occurrence of HHS was confirmed for the first time in Korea from chickens submitted for diagnosis to our laboratory from broiler and baeksemi farms. Clinical signs included depression, inappetence, ruffled feathers and a increase in mortality. At necropsy, severe hydropericardium and hepatic necrosis was founded characteristically and the most remarkable microscopic changes were seen in the liver. These included basophilic intranuclear inclusion bodies in the hepatocytes, massive hemorrhages and necrosis in the liver parenchyma. We could also identify fowl adeno-virus(FAV) by polymerase chain reaction(PCR) and electro-microscopic confirmation. Abbreviation: HHS=hydropericardium hepatitis syndrome, EM=electron microscopy, FAV=fowl adenovirus, PCR=polymerase chain reaction.

• Journal of Veterinary Clinics
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• v.34 no.4
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• pp.310-312
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• 2017

A five-month-old African grey parrot was presented with alopecia, yellowish diarrhea, depression, and paralysis in the veterinary medical center, Chungbuk National University. The patient died 3 h later after hospitalization. For the accurate diagnosis, necropsy was performed and fungi were detected in the air sac. PCR was done for the viral detection which caused the alopecia, and for the species identification of fungi. Final diagnosis was a multi infection with avian circoviruses that caused psittacine beak and feather disease (PBFD), avian polyomavirus cause budgerigar fledgling disease (BFD), and Aspergillus fumigatus. This is the first report of a multi infection in South Korea.