• Korean Journal of Veterinary Service
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• v.43 no.4
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• pp.257-259
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• 2020

Ornithobacterium rhinotracheale (ORT) causes pneumonia, airsacculitis, and pleuritis in chickens and other avian species. Little is known about the seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea. The purpose of this study was to determine the seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea from May to September 2019. A total of 460 chickens in 28 flocks were tested for antibodies to ORT by using commercial enzyme-linked immunosorbent assay (ELISA) kit. The seroprevalence of ORT antibodies in the flocks was 100% (28/28) and the overall seroprevalence in individual chickens was 98.91% (455/460). This survey indicated the high seroprevalence of ORT in layer chickens in Gyeonggi province, South Korea. Therefore, measures should be executed to control ORT in layer chickens in this province.

• Korean Journal of Veterinary Service
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• v.43 no.3
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• pp.197-200
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• 2020

This study was performed to determine the seroprevalence of reticuloendotheliosis virus (REV) infection in layer chickens in Gyeonggi province, South Korea. Serum samples were collected from 820 layer chickens on 56 flocks in Gyeonggi province. The samples were tested for specific antibodies against REV using commercial enzyme-linked immunosorbent assay (ELISA). The seroprevalence of REV antibodies in the flocks was 62.50% (95% Confidence interval (CI) 49.33~74.40) and the overall seroprevalence in individual chickens was 39.27% (95% CI 35.97~42.65). The results of the present survey indicate that REV infection is prevalent in layer chickens in Gyeonggi province, South Korea. Therefore, effective measures should be taken to prevent and control REV of layer chickens in this province.

• Korean Journal of Veterinary Service
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• v.18 no.2
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• pp.152-157
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• 1995

A total of 1050 layer and broiler chickens from 63 flocks of 21 poultry farms in South-Kyeonggi area, aged from 1 to 18 weeks, were investigated for the prevalence of Cryptosporidium baileyi infection from May 1992 to March 1993. The results have shown that 44 chickens(4.19%) were infected with C.(baileyi during the period of investigation) Fecal samples were treated by using Sheather's flotating technique and were examined under the light and phase contrast microscopy and then stained by Kinyoun method. Cryptosporidium oocysts were found in 35 out of 650 broilers(5.4%) and 9 out of 400 layer chickens(2.3%) aged mainly from 2 to 12 weeks. The regional infection rate were 4.7% in Pyeong-taek, 5.1% in An-sung and 2.3% in Yong-in, respectively. The average size of isolated oocyst was about $5.23{\times}4.92{\mu}m$ and the oocysts were orally inoculated into 2-day-old SPF chickens for the histological examination of oocyst in bursa of Fabricius. The study has concluded that C. baileyi infects chickens and oocysts were isolated in South-Kyeonggi area.

• Korean Journal of Veterinary Service
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• v.41 no.1
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• pp.21-27
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• 2018

Fowl adenovirus (FAdV) and chicken anemia virus (CAV) have gained much importance as an immunosuppressive and economically important emerging pathogen of poultry. This study was carried out to investigate the prevalence of FAdV and CAV infection in chickens. The groups were divided into Korean native chickens, broiler, layer hens and broiler breeder and set up groups according to age. As results, 12.5% of the native chicken, 2.5% of broiler and 6.7% of layer chicken were positive, respectively by PCR for FAdV. Serological test showed that 84.8%, 79.0%, 97.7% and 96.1% of chickens were positive for antibody to FAdV in native chickens, broiler, layer hens and broiler breeder. The prevalence of CAV infection were 20.0%, 7.5%, 16.7% and 10.0%, based on CAV gene detection by PCR. In serological test of CAV, 40.6%, 35.9%, 84.8% and 73.9% of chickens were positive in that groups.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.11
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• pp.1610-1615
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• 2008

Natto is a Japanese traditional soybean product fermented by Bacillus natto. The effects of dried fermented soybean (natto) supplement on egg production and egg qualities of layer chickens was studied with regard to the effective use of various waste foods in Japan. Dried natto, prepared by heating at $60^{\circ}C$, was added to a basic diet at a level of up to 3%. Forty 166-wk-old layer chickens (Rhode Island Red) were randomly divided into 4 groups and five layer chickens were used in each group with two replicates. Layer chickens in group 1 were fed a basic diet as the control. The remaining 3 groups were fed the basic diet supplemented with dried natto at levels of 1, 2, and 3% (w/w), respectively. The result did not show improvements in egg production or feed conversion ratio of layer chickens even when 3% dried natto was added to the control diet. The egg qualities including egg weight, eggshell strength and thickness, yolk color, yolk weight, albumen height, and Haugh unit were also not improved. However, the feeding of dried natto changed the cholesterol content in the egg yolk. The supplementation of dried natto showed the tendency to decrease the yolk cholesterol after 12-wk of feeding compared to the control diet though it did not change plasma cholesterol levels in the blood. On the other hand, yolk cholesterol decreased significantly after 12-wk of feeding 3% dried natto (p<0.05).

• Korean Journal of Poultry Science
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• v.30 no.1
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• pp.55-59
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• 2003

A necrotizing skeletal myopathy was diagnosed in three flocks of 30,000 thirty-eight-week-old layer breeder chickens. The mortality attributed to the myopathy was 17.7%, 12.3% and 21.1% in flock A, B and C, respectively. Clinically, chickens were showed depression, anorexia, posterior paresis, inability to rise, incoordination, reluctance to move, and leg trembling and weakness. The most striking findings at necropsy was pale streaking in the muscles of the thighs and legs. Microscopic lesions included myofiber degeneration and necrosis with massive cellular proliferation interpreted as sarcolemmal nuclei proliferation. Plasma creatine kinase, asparte aminotransferase and akaline phosphatase were markedly elevated. In conclusion, author suggested that submitted chickens were affected by ionophores poisoning.

• Korean Journal of Veterinary Service
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• v.22 no.3
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• pp.221-237
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• 1999

To investigate the specificity of rapid slide agglutination test for pullorum-gallinarum diseases and to obtain a basic data for avian salmonellosis control, salmonella isolation was peformed for the layer chickens positively reacted in pullonlm-typhoid agglutination test. The biochemical, serological and antimicrobial properties of the isolates were examined. The results obtained through this study were summarized as follows; 1. Of 2,384 chickens tested by the agglutination test, 606 chickens (25.4%) were positive reactors. 154 of 606 reactors and 49 of the non-reacting chickens were investigated for salmonella isolation, resulting in isolation of 68 strains of salmonellae from 27 chickens. 2. By organs, the isolation frequency from liver, cecum, spleen, ovary and gall bladder showed 8.9% (18 strains), 8.9% (18 strains), 7.4% (15 strains), 4.4% (9 strains) and 3.9% (8 strains), respectively. 3. By culture medium the combination of selenite broth and MacConkey agar revealed the highest isolation rate and the enrichment culture by delayed secondary enrichment culture method was found the most effective for salmonella isolation. 4. The serotypes of 68 salmonella isolates were identified as 3 strains of S pullorum, 24 strains of S gallinarum, 15 strains of S typhimurium, 8 strains of S enteritidis, 7 strains of S paratyphi A, 5 strains of S typhimurium and 6 strains of the other salmonellae. 5. The serotypes of 8 salmonella strains isolated from 49 chickens non-reacting in pullorum-typhoid agglutination test were identified as 3 strains of S typhimurium and 5 strains of S infantis. 6. When 24 chickens of which 68 strains of salmonellae isolated were examined by microplate agglutination test, the average antibody titer for pullorum antigen was $2^{5.25}$. The chickens at antibody titer between $2^3$ and $2^5$ showed the higher frequency of isolation as compared with the chickens at the other titers. 7. When salmonella isolates were tested the antimicrobial drug sensitivity by disk diffusion method, S paratyphi A were highly sensitive by 100% to ATM and GM, S typhimurium, by 88% to AM, CIP, IMP and TN, S infantis, by 100% to AM, CRO, ENR and PIP, S enteritidis,by 100% to IMP and PIP, S pullorum, by 100% to ATM, CRO, ENR and PIP and S gallinarum, by 92% to CRO, CIP and PIP.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.10
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• pp.1445-1450
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• 2005

This experiment was conducted to evaluate the effect of feed withdrawal (F) and heat acclimatization (A) on malebroiler and -layer chickens responses to acute heat stress (AHS) at four weeks of age. Totals of ninety male chicks of broiler or layer type were randomly allocated into 30 pens of grower batteries with raised wire floors. Chicks were subjected to F and A three times a week through the first three weeks of age. At each time, feed withdrawal and heat acclimatization (T = $35^{\circ}C$) lasted for six and four hours, respectively. Feed consumption (FC), body weight (BW), and feed conversion ratio (FCR) were recorded weekly for broiler type chickens only. At four weeks of age, all groups of chickens were exposed to AHS (T = $39{\pm}1^{\circ}C$) for three hours. Before and after AHS challenge, body temperature (Tb), heterophil (H), and lymphocyte (L) counts were recorded, and H/L ratio was calculated. Antibody (Ab) response to sheep red blood cells (SRBC) was assessed from all treatments without being exposed to AHS. Group F of broiler-type chickens weighed less (p<0.05) compared to control group. Also, both A and F groups of broiler-type chickens consumed less (p<0.05) feed when compared to control group. Acute heat stress elevated Tb of all treatment groups, however the increase was more profound (p<0.001) in broiler chicks. Broiler chicks of both A and F groups showed a tendency to have higher (p = 0.08) Tb when compared to control group. Acute heat stress elevated (p<0.001) H/L ratio in both types of chickens. Broiler chicks maintained higher (p<0.001) H/L ratio. Both F and A groups reduced (p<0.01) the level of elevation in H/L ratio compared to control groups of both types of chickens. Neither A nor F group affected the Ab production in response to SRBC. However, there was a tendency towards higher Ab responses in F group when compared to other groups in both types of chickens. Results of the present study demonstrate that previous history of feed withdrawal or episodes of heat exposures improved chicks'physiological withstanding of AHS and a tendency to improved humoral immune response.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.12
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• pp.1805-1811
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• 2016

The goal of this study was to estimate the emissions of greenhouse gases (GHG), namely methane ($CH_4$), nitrous oxide ($N_2O$), and carbon dioxide ($CO_2$) from poultry and pig production in South Korea over the last 10 years (2005 through 2014). The calculations of GHG emissions were based on Intergovernmental Panel on Climate Change (IPCC) guidelines. Over the study period, the $CH_4$ emission from manure management decreased in layer chickens, nursery to finishing pigs and gestating to lactating sows, but there was a gradual increase in $CH_4$ emission from broiler chickens and male breeding pigs. Both sows and nursery to finishing pigs were associated with greater emissions from enteric fermentation than the boars, especially in 2009. Layer chickens produced lower direct and indirect $N_2O$ emissions from 2009 to 2014, whereas the average direct and indirect $N_2O$ emissions from manure management for broiler chickens were 12.48 and $4.93Gg\;CO_2-eq/yr$, respectively. Annual direct and indirect $N_2O$ emissions for broiler chickens tended to decrease in 2014. Average $CO_2$ emission from direct on-farm energy uses for broiler and layer chickens were 46.62 and $136.56Gg\;CO_2-eq/yr$, respectively. For pig sectors, the $N_2O$ emission from direct and indirect sources gradually increased, but they decreased for breeding pigs. Carbon dioxide emission from direct on-farm energy uses reached a maximum of $53.93Gg\;CO_2-eq/yr$ in 2009, but this total gradually declined in 2010 and 2011. For boars, the greatest $CO_2$ emission occurred in 2012 and was $9.44Gg\;CO_2-eq/yr$. Indirect $N_2O$ emission was the largest component of GHG emissions in broilers. In layer chickens, the largest contributing factor to GHG emissions was $CO_2$ from direct on-farm energy uses. For pig production, the largest component of GHG emissions was $CH_4$ from manure management, followed by $CO_2$ emission from direct on-farm energy use and $CH_4$ enteric fermentation emission, which accounted for 8.47, 2.85, and $2.82Gg-CO_2/yr$, respectively. The greatest GHG emission intensity occurred in female breeding sows relative to boars. Overall, it is an important issue for the poultry and pig industry of South Korea to reduce GHG emissions with the effective approaches for the sustainability of agricultural practices.

• Journal of Microbiology and Biotechnology
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• v.23 no.10
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• pp.1478-1483
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• 2013

In this study the isolation and characterization of three bacteriophages (ST4, L13, and SG3) infecting Salmonella gallinarum were carried out. They were further tested for their in vivo efficacy in phage therapy. All three phages belong to the Siphoviridae family with isometric heads and non-contractile tails. They have a broad host range among serovars of Salmonella enterica. The burst sizes were observed to be 1670, 80, and 28 for ST4, L13, and SG3, respectively. The in vivo efficacy of the phages was tested in chickens. Layer chickens were challenged with S. gallinarum, whereas contact chickens were cohabited without direct challenge. Each bacteriophage was orally inoculated in the form of feed additives. Mortality was observed and S. gallinarum was periodically re-isolated from the livers, spleens, and cecums of the chickens. Bacterial re-isolation from the organs and mortality decreased significantly in both challenged and contact chickens treated with the bacteriophages compared with untreated chickens serving as the control. The three bacteriophages may be effective alternatives to antibiotics for the control of fowl typhoid disease in chickens.