• Korean Journal of Veterinary Service
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• v.46 no.3
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• pp.211-218
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• 2023

This study was carried out to investigate the prevalence and antimicrobial resistance of Salmonella serotypes in duck farms of Jeollanam-do Province, South Korea. A total of 1112 samples (breeder ducks, 286; broiler ducks, 826) were collected from 196 duck farms (breeder duck farms, 25; broiler duck farms, 171) between January 2018 and November 2019. The total prevalence of Salmonella serotypes was 45.4% (89/196) in the duck farms, with no significant difference between prevalence in breeder and broiler duck farms (48% and 45%, respectively; P>0.05). The most prevalent serotype among the 127 Salmonella isolates was Salmonella Typhimurium (20.5%) followed by Salmonella Albany (17.3%), Salmonella Hadar (15.7%), and Salmonella Enteritidis (11.8%). Maximum resistance was observed against penicillin (78.74%), followed by tetracycline (68.50%), and kanamycin (65.35%). Of the 127 isolates, 117 (92.13%) were resistant to ≥3 antimicrobials and 2 to all 18 antimicrobials. Our results demonstrate the presence of Salmonella strains and their resistance to multiple antimicrobials, thus indicating a public health concern in South Korea. The emergence of Salmonella stains that are resistant to multiple drugs highlight the need for careful use of antimicrobials in duck farms.

• Korean Journal of Veterinary Service
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• v.38 no.1
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• pp.61-64
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• 2015

Highly pathogenic avian influenza (HPAI) occurred in the breeder duck farms in Jeonbuk of in Korea on January to February 2014. Clinically, the most ducks showed various signs from depression, dropped egg production and feed consumption to even, death. The most commonly gross changes were hepatomegaly, splenomegaly, petechial and ecchymotic hemorrhage on the liver surface, a white stripe on the cardiac muscle, multifocal hemorrhagic foci in pancreas, and severely hemorrhagic embryos. The most significant signs of H5N8 virus was supposed to specific on ducks. The viral antigen was mainly detected in the endothelium of blood vessels of various organs and tissues, peripheral nerves, and neuronal cells. Based on the above results, we identified that HPAI H5N8 induced systemic infection in the adult breeder ducks.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.245-250
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• 2019

Newcastle disease (ND) is an infectious poultry disease that caused high mortality and reduced egg production. NDVs are regularly present in the domestic duck population. And ducks play a possible role in the maintenance and transmission of NDVs. While we were monitoring the Avian Influenza, NDVs were isolated from field samples by accident. So we analysed the biological and genetic characteristics of these viruses. Lentogenic NDVs were isolated from two farms among twenty breeder duck farms. The ages of ducks were 39 weeks old in the 'A' farm and 3~72 weeks old in the 'B' farm. And they were not inoculated with the NDVs vaccine. In the biological characteristics, the both viruses which separated from the farm 'A' and 'B' were thermostable. The amino acid sequence of a site from 112 to 119 in the fusion (F) protein was 'GKQGRLIG' which has monobasic motif in the samples of both farms. And this means the separated NDVs are lentogenic. Phylogenetic analysis was performed by entire nucleotide sequence of F protein. The virus strains from the A farm (MN095239) and the B farm (MN095240) belonged to class II genotype I. Using the analysis of whole F protein nucleic acid sequence, the MN095239 (GenBank) had homology with Ulster strain about 99.95% and the MN095239 (GenBank) had homology with KR/CK/KU_LBM255/09 strain about 99.89%. NDV surveillance is needed to investigate epidemiological relationship of domestic breeder duck isolates in Korea.

• 한국환경농학회:학술대회논문집
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• 2009.07a
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• pp.220-227
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• 2009

For last about 10 years, the Republic of Korea experienced 3 times of outbreaks of highly pathogenic avian influenza (HPAI) from 10 December 2003 to 30 April 2004 (a total number of 19 outbreaks), 22 November 2006 to 6 March 2007 (a total number of 7 outbreaks), and 1 April 2008 to 12 May 2008 (a total number of 33 outbreaks). Among the totally 59 outbreaks, the infected premises included 35 chicken farms, 17 duck farms, 1 quail farm, and 6 farms rearing mixed species. Control measures were applied according to the HPAI standard operation procedure including depopulation of all infected and suspected flocks, movement restrictions, and disinfection of the infected farms within a 500-meter radius. Including movement restrictions, stringent control measures were additionally applied to two designated zones: the protection zone was an area within a 3-kilometer radius of the outbreak farm, and the surveillance zone was an area between a 3- to 10-kilometer radius of the outbreak farm. Farms with dangerous contacts and/or all of poultry within the protection zone was subjected to preemptive culling. Epidemiological investigations were also carried out including trace-back and trace-forward investigations to identify possible sources of spread and dangerous contact farms. Investigation teams conducted on-site examination of farm premises and facilities, interview with farm owner and staff, and review of records. Genetic and pathogenic characteristics of the virus isolates, and the results of the various surveillance activities were also analyzed. HPAI surveillance conducted in Korea includes passive surveillance of investigating notified cases, and active surveillance of testing high risk groups and areas. HPAI is a notifiable disease in Korea and all suspect cases must be reported to the veterinary authorities. Cases reported for other poultry diseases that require differential diagnosis are also tested for HPAI. Active surveillance includes annual testing of breeder duck farms, broiler duck farms and wild bird surveillance, which is concentrated during the autumn and winter. Surveillance activities conducted prior to the outbreaks have shown no evidence of HPAI infection in Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.9
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• pp.1215-1224
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• 2017

Objective: To assess the differences in ovarian transcriptomes in Shan Ma ducks between their peak and late stages of egg production, and to obtain new transcriptomic data of these egg-producing ducks. Methods: The Illumina HiSeq 2000 system was used for high throughput sequencing of ovarian transcriptomes from Shan Ma ducks at their peak or late stages of egg production. Results: Greater than 93% of the sequencing data had a base quality score (Q score) that was not less than 20 (Q20). From ducks at their peak stage of egg production, 42,782,676 reads were obtained, with 4,307,499,083 bp sequenced. From ducks at their late stage of egg production, 45,316,166 reads were obtained, with 4,562,063,363 bp sequenced. A comparison of the two datasets identified 2,002 differentially expressed genes, with 790 upregulated and 1,212 downregulated. Further analysis showed that 1,645 of the 2,002 differentially expressed genes were annotated in the non-redundant (NR) database, with 646 upregulated and 999 downregulated. Among the differentially expressed genes with annotations in the NR database, 696 genes were functionally annotated in the clusters of orthologous groups of proteins database, involving 25 functional categories. One thousand two hundred four of the differentially expressed genes with annotations in the NR database were functionally annotated in the gene ontology (GO) database, and could be divided into three domains and 56 categories. The three domains were cellular component, molecular function, and biological process. Among the genes identified in the GO database, 451 are involved in development and reproduction. Analysis of the differentially expressed genes with annotations in the NR database against the Kyoto encyclopedia of genes and genomes database revealed that 446 of the genes could be assigned to 175 metabolic pathways, of which the peroxisome proliferator-activated receptor signaling pathway, insulin signaling pathway, fructose and mannose metabolic pathways, gonadotropin releasing hormone signaling pathway and transforming growth factor beta signaling pathway were significantly enriched. Conclusion: The differences in ovarian transcriptomes in Shan Ma ducks between their peak and late stages of egg production were elucidated, which greatly enriched the ovarian transcriptomic information of egg-producing ducks.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.133-137
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• 2009

This study was conducted to evaluate the performance of Cherry Valley and Grimaud strain. A total of two hundred eighty eight, one day old duck breeders (Cherry Valley and Grimaud strain) were randomly divided into two groups with 4 replicates of 36 birds each and fed a commercially available diet for 24 weeks. Overall body weight gain was significantly higher in Cherry Valley (3,064 g) than in Grimaud strain (2,851 g). Feed intake was significantly increased in Grimaud strain compared with Cherry Valley strain (p<0.05). Viability of Grimaud strain showed 100.0% and was higher than that of Cherry Valley strain. Uniformity was not statistically different between Cherry Valley and Grimaud strains.

• Journal of Mushroom
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• v.16 no.1
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• pp.51-56
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• 2018

In Korea, the oak mushroom (Lentinula edodes) is highly preferred by consumers in the food industry and makes up about 97.7% of the total forest mushroom production. This indicates that the oak mushroom is an important non-timber forest product in Korea. Recently, the breeding and development of new cultivars of L. edodes have been actively initiated, and the development of molecular markers that are able to identify and discriminate the new cultivars is crucial for protecting the breeder's rights. This study was carried out to develop a cleaved amplified polymorphic sequence (CAPS) marker for the identification and discrimination of a new cultivar, Sanmaru 2ho from the 37 other oak mushroom cultivars. A single nucleotide polymorphism (SNP) was identified at the $1,803,483^{rd}$ position of scaffold2 in the genome of Sanmaru 2ho. The amplified DNA containing the SNP of Sanmaru 2ho was uniquely not cleaved by the restriction enzyme, Hha I, and thus Sanmaru 2ho was successfully distinguished from the other oak mushroom cultivars.

• Korean Journal of Poultry Science
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• v.31 no.2
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• pp.119-128
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• 2004

Highly Pathogenic Avian Influenza (HPAI) is a very acute systemic disease in poultry, particularly in chickens and turkeys caused by HPAI viruses. An outbreak of HPAI caused by subtype H5N1, was first reported in a broiler breeder farm on December 10, 2003 in Korea, although there had been twenty one outbreaks of the disease reported in the world before. Since mid-December 2003, eight Asian countries have confirmed outbreaks of HPAI due to the same subtype. The outbreak has also resulted in at least twenty three fatal human cases in Vietnam and Thailand as of May 17, 2004 according to the WHO. Regarding the first outbreak of recent Asian HPAI, it has been suspected that some Asian countries with the exception of Korea and Japan veiled the fact of HPAI outbreaks since the last half of 2003, even though it was first reported in Korea. There have been total nineteen outbreaks of HPAI among chicken and duck farms in 10 provinces in Korea since Dec. 2003 and approximately 5,280,000 birds were slaughtered from 392 farms for eradication of the disease and preemptive culling. The origin of the H5Nl HPAI virus introduced into the country are unknown and still under epidemiological investigation. Current status of outbreaks and characteristics of HPAI will be reviewed and discussed on the basis of genetic, virological, clinicopathological, and ecological aspect, as well as future measures for surveillance and prevention of the disease in Korea.