• Korean Journal of Poultry Science
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• v.38 no.1
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• pp.45-50
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• 2011

A case of aspergillosis in 39-day-old layer chickens having a history of gradual emaciation and subsequently death with nervous signs such as torticollis and lack of equilibrium was documented. Based on the results from serology and polymerase chain reaction (PCR) test, this flock was not affected with known viral or bacterial diseases. On postmortem examination of the affected birds, multiple white to yellow nodules measuring 1~5 mm in diameter were observed in the lungs, cerebrum, liver and kidney. Microscopically, these nodules were identified as granulomatous lesions characterized by mixed population of multinucleated giant cells and lymphocytes. By periodic acid-schiff staining and nucleotide sequencing analysis, Aspergillus flavus with characteristic septate and branched hyphae were identified in the granuloma of lung and cerebrum. This case was a chronic and multisystemic aspergillosis specialized to central nervous system caused by Aspergillus flavus infection in the layer flocks.

• Korean Journal of Poultry Science
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• v.38 no.4
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• pp.305-313
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• 2011

This study was conducted to investigate the effects of housing systems on the productivity and physiological response as stress indicators in White Leghorn chickens. The chickens subjected to the conventional cages had a significantly lower viability, hen-housed egg production, egg weight and body weight compared with those to the floor pens. However, the hens housed in the conventional cages had a shorter day of the first egg and a greater egg quality compared with those housed in the floor pens. In addition, this study was also investigated to identify biological markers for assessing the physiological response of chickens under stress conditions. As biological markers, the amount of telomeric DNA was analyzed by quantitative fluorescent in situ hybridization on the nuclei of cells. The DNA damage rate of lymphocytes was also quantified by the comet assay. The amount of telomeric DNA of the lymphocytes, kidney and spleen was significantly higher in the chickens under floor pens than those under conventional cages. The DNA damage also increased in chickens raised under conventional cages, as compared to the chickens under floor pens. As results, we conclude that the chickens housed in conventional cages have a greater stressful status than those housed in floor pens.

• Korean Journal of Poultry Science
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• v.39 no.4
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• pp.283-290
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• 2012

The objective of this study was to compare the growth performance between Korean native layer chickens and imported layer chickens at early rearing stage. Total number of chicks analyzed in this study was 276 and feeding period was conducted from July 24, 2012 for 10 weeks. Five strains including 2 Korean native strains: A=Korean Native Black (Chungcheongbuk-do) and B=Korean Native Yellowish Brown (Gyeongsangbuk-do) and 3 imported layer strains: C=White Leghorn (Gyeongsangnam-do), D=White Leghorn (Seoul), and E=Ameraucanas (Gyeongsangbuk-do) were used to analyze the following traits such as fertility, hatchability, body weight at a different growing stage, average body weight gain, and feed conversion ratio. The fertilities and hatchabilities of strains were 93.88% and 95.65% in strain A, 81.75% and 86.24% in strain B, 82.25% and 88.15% in strain C, 79.25% and 90.85% in strain D, and 71.50% and 88.11% in strain E, respectively. A viability was excellent in strains A and E to be more than 98% and was low in strain D to be 86.67% at a whole week. The strain A had greater body weight during growing stages (p<0.05) than the other strains. The shank length of strain D of $56.69{\pm}3.27mm$ was the highest value at 10 weeks of age among strains (p<0.05). The phenotypic correlation coefficients of strains A and D between an average body weight gain and a shank length were 0.63 and 0.73 during 0~2 wk, 0.70 and 0.55 during 2~4 wk, 0.55 and 0.54 during 4~6 wk, 0.50 and 0.24 during 6~8 wk, and 0.46 and 0.29 during 8~10 wk, respectively. The Korean native hens may have potential abilities to be used as an excellent seed stock for poultry industry.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.4
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• pp.471-482
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• 2009

Nutrient availability may control muscle growth directly and indirectly through its influence on regulatory factors. We analyzed the effects of nutrient availability on the breast muscle insulin-like growth factor system. Real time RT-PCR was used to quantify the level of transcription in breast muscle from Langshan (LS) layer and Arbor Acres (AA) broiler chickens subjected to different feeding regimens during embryonic and postnatal development. The AA chickens were fed AA diet (AA, control group) while the LS chickens were either fed LS diet (LL) or AA diet (LA). According to our results, insulin-like growth factor (IGF)-II (embryonic day 16 (E16) - postnatal day 42 (P42)), IGF-I receptor (IGF-IR, E18-P42), and IGF binding protein (IGFBP)-2 (E18-P42), -5 (E16-P14), -7 (E12-P0), and -3 (E12-P0) were positively correlated with IGF-I, while IGFBP-3 (P0-P28) was negatively correlated with IGF-I. In comparison, IGF-IR (E18-P42), IGFBP-2 (E18-P42), IGFBP-5 (E14-P0), and IGFBP-3 (E16-P0) were positively correlated with IGF-II, while IGF-IR (E10-E16) and IGFBP-3 (P0-P28) were negatively correlated with IGF-II. Moreover, IGFBP-2 (E16-P42), -7 (E10-E16), and -3 (E10-E16) were positively correlated with IGF-IR, while IGFBP-3 (P0-P28) was negatively correlated with IGF-IR. Finally, IGFBP-7 (E12-P0) was positively correlated with IGFBP-3, while IGFBP-2 (P0-P28) and -7 (P0-P42) were negatively correlated with IGFBP-3. Overall, the AA chickens exhibited higher levels of IGF-I, IGF-IR, and IGFBP-2 mRNA expression than the LL chickens, while the opposite was true for IGFBP-7. No strain differences in IGF-I, IGF-IR, and IGFBP-7 mRNA expression were detected between LA and AA chickens; however, a strain difference was observed for IGFBP-2. LA chickens exhibited higher levels of IGFBP-2 than LL chickens, while the opposite was true for IGFBP-7. Our data show the first evidence that certain genes may be correlated during specific developmental periods and that strain differences in the expression of those genes in LS and AA chickens are due to differential responses to the same diet.

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.96-102
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• 1990

The immune responses of commercial layer chickens against Newcastle disease(ND) were compared among different administration methods and times of vaccination during 4 weeks of age. A total of 372 day-old chickens were divided into 4 groups of 93 birds each. Each of 3 groups was received a commercially available B$_1$live vaccine via drinking water, eye instillation or spray method at one, 14 and 28 days of age. One group was used as an unvaccinated control. At two and 4 weeks after each time of vaccination, 15 birds from each group were collected randomly out and challenged with virulent ND virus at the dose of $10^5E1D_{50}$ per bird. Ten to 15 birds from each group were bled at two weeks intervals from day old to 8 weeks of age for hemagglutination inhibition antibody titer, The protection rate was generally low regardless of the times of vaccination although two or more times vaccination gave higher protection than once vaccination. The low protection was considered due to low titer of the vaccine used since the vaccine titer was less than $10^{3.5}EID_{50}$ per bird. Spray method gave better protection compared to eye instillation or drinking water method which resulted in lowest response. Majority of birds showed clinical signs of ND between 3 and 6 days after challenge. Death occured one or two days after onset of symptoms. Major clinical signs observed were depression(94%), anorexia(84%), diarrhoea(29%), difficult breath(15%) and torticollis(10%). Hemorrhagic lesions on post mortem were seen in duodenum(51%), trachea(35%), illeum(13%), ceacal tonsil(11%), proventriculus(10%) and some other odrgans.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.3
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• pp.341-349
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• 2019

Objective: Internal organs indirectly affect economic performance and well-being of animals. Study of internal organs during later layer period will allow full utilization of layer hens. Hence, we conducted a genome-wide association study (GWAS) to identify potential quantitative trait loci or genes that potentially contribute to internal organ weight. Methods: A total of 1,512 chickens originating from White Leghorn and Dongxiang Blue-Shelled chickens were genotyped using high-density Affymetrix 600 K single nucleotide polymorphism (SNP) array. We conducted a GWAS, linkage disequilibrium analysis, and heritability estimated based on SNP information by using GEMMA, Haploview and GCTA software. Results: Our results displayed that internal organ weights show moderate to high (0.283 to 0.640) heritability. Variance partitioned across chromosomes and chromosome lengths had a linear relationship for liver weight and gizzard weight ($R^2=0.493$, 0.753). A total of 23 highly significant SNPs that associated with all internal organ weights were mainly located on Gallus gallus autosome (GGA) 1 and GGA4. Six SNPs on GGA2 affected heart weight. After the final analysis, five top SNPs were in or near genes 5-Hydroxytryptamine receptor 2A, general transcription factor IIF polypeptide 2, WD repeat and FYVE domain containing 2, non-SMC condensin I complex subunit G, and sonic hedgehog, which were considered as candidate genes having a pervasive role in internal organ weights. Conclusion: Our findings provide an understanding of the underlying genetic architecture of internal organs and are beneficial in the selection of chickens.

• Korean Journal of Veterinary Research
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• v.50 no.4
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• pp.323-326
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• 2010

Candidiasis is a mycosis caused by the mycelial yeast of the Candida genus which is opportunistic pathogen of humans, animals, and birds. Under some conditions such as prolonged antibiotic therapy, overcrowding, and immunosuppression, the opportunistic Candida can cause disease. Chicken candidiasis is sporadically occurred and characterized by unsatisfactory growth, listlessness, roughness of feathers, and death. A case of 23 weeks old layer with history of increased mortality and anemia was submitted to our Lab. At necropsy, the characteristic lesions were observed in the crop and proventriculus. The whitish pseudomembrane, that are peeled easily, was found in the crop. Proventriculus was swollen and the mucosa was covered with hemorrhagic exudate. The histological changes of the affected crop are epithelial hyperplasia, hydropic degeneration, and mycelia formation. Smears made from the necrotic mucosal surfaces of the crop revealed the presence of large number of yeast cells and mycelia. Pure cultures of yeast colonies were obtained from the potato dextrose agar. The yeast cells were identified as Candida albicans by gene sequencing. To our knowledge, this is the first report of candidiasis in chickens with anemia in Korea.

• Korean Journal of Veterinary Research
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• v.51 no.3
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• pp.209-216
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• 2011

Four strains of fowl adenovirus (FAdV) were isolated from 4 flocks of broiler or layer chickens affected by hydropericardium syndrome in Korea. These FAdVs were classified as serotype 4 by restriction fragment length polymorphism patterns of hexon genes and whole genomes. The virus exhibited cytopathic effects consisting of rounding, ballooning and clustering in primary chicken embryo liver cell cultures. In transmission electron microscopy, virus particles in hexagonal shape aggregated exclusively in the nuclei of hepatocytes of the chickens as the typical appearances in adenovirus infections. Buoyant density of the virus in cesium chloride (CsCl) was 1.34 g/mL. The virus was stable to chloroform, ether, 50~70% ethanol, acidic condition at pH 3, 0.25% trypsin (1 : 250), heat at $50^{\circ}C$ for 30 min, but labile to 100% ethanol, heat at $52{\sim}60^{\circ}C$ for 30 min, 1 M $MgCl_2$ at $50^{\circ}C$ for 1 h, 1 : 2,000 formalin (37%). All of the physicochemical properties pertained to the characteristics of adenoviruses. Eight viral polypeptides were determined in CsCl-purified virus by sodium dodecyl sulfate-polyacrylamide gel electrophoresis.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.8
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• pp.1102-1107
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• 2003

The ES cell can provide a useful system for studying differentiation and development in vitro and a powerful tool for producing transgenic animalds. To investigate the culture condition of chicken embryonic stem (CES) cells which can retain their multipotentiality or totipotency, three kinds of feeder layer cells, SNL cells, primary mice embryonic fibroblasts (PMEF) cells and primary chicken embryonic fibroblasts (PCEF) cells, were used as the feeder cells in media of DMEM supplemented with leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF) and stem cell factor (SCF) for co-culture with blastoderm cells from stage X embryos of chicken. The alkaline phosphatase (AKP) test, differentiation experiment in vitro and chimeric chicken production were carried out. The results showed that culture on feeder layer of PMEF yielded high quality CES cell colonies. The typical CES cells clone shape revealed as follows: nested aggregation (clone) with clear edge and round surface as well as close arrangement within the clone. Strong alkaline phosphatase (AKP) reactive cells were observed in the fourth passage cells. On the other hand, the fourth passage CES cells could differentiate into various cells in the absence of feeder layer cells and LIF in vitro. The third and fourth passage cells were injected into the subgerminal cavity of recipient embryos at stage X. Of 269 Hailan embryos injected with CES cells of Shouguang Chickens, 8.2% (22/269) survived to hatching, 5 feather chimeras had been produced. This suggests that an effective culture system established in this study can promote the growth of CES cells and maintain them in the state of undifferentiated and development, which lays a solid foundation for the application of CES cells and may provide an alternative tool for genetic modification of chickens.

• Korean Journal of Veterinary Service
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• v.35 no.1
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• pp.9-17
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• 2012

The objective of the present study was to isolate and identify infectious bursal disease viruses (IBDVs) from broiler and layer chickens of outbreaks of infectious bursal disease (IBD) in three districts of Bangladesh. A total of 70 bursal samples were collected from dead broiler (n=40) and layer (n=30) chickens showing specific lesions of IBD from seven commercial poultry farms of three different districts (Mymensingh, Chittagong and Tangail) of Bangladesh during the year 2007. Five representative bursal samples from each farm were used for the isolation of IBDVs using 9-day-old embryonated eggs of seronegative flock of layer birds and for identification the samples were subjected to agar gel immunodiffusion test (AGIDT), immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Out of 35 bursal samples, IBDVs were successfully isolated from 28 (80%) samples. By AGIDT, 32 (91.4%) samples were found positive for IBDV antigen. Results of AGIDT clearly indicated that IBDVs detected in 29 bursal samples of six affected farms were identical to each other but not to IBDVs present in the remaining three samples of another farm. Indirect immunoperoxidase staining of the bursal sections revealed the presence of IBDV antigen in 32 (91.4%) samples and the IBDV antigen was detected mainly in the cortex of the lymphoid follicles of the bursal tissues. In histopathology, cell depletion, atrophy and necrosis were observed in many bursal follicles with severe edema of interfollicular septa. Of the 35 bursal samples, 34 (97.1%) samples generated 254 bp product by RT-PCR. In conclusion, the results of virus isolation and identification by AGIDT, IHC and the analysis of viral genome by RT-PCR confirmed the outbreaks of acute IBD in commercial poultry of Bangladesh. Moreover, histopathological findings and results of AGIDT gave a clear indication that the isolates from six outbreaks were different from classical strain and it seems to be of very virulent strain. On the other hand, the isolates from the other outbreak were similar to the classical strain.