• Development and Reproduction
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• v.12 no.3
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• pp.207-213
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• 2008

In order to monitor the developmental features of embryos, larvae, and juveniles of chub mackerel, Scomber japonicus, the fertilized eggs were obtained by artificial insemination. The fertilized eggs were spherical in shape and floated separately. Their membrane and yolk having 1 oil globule were transparent. The transparent eggs, having one oil drop in the yolk, were $0.94{\sim}1.02\;mm$ (mean, $0.95{\pm}0.03\;mm$) in diameter. The fertilized eggs started hatching at 51 hrs after fertilization in $20{\pm}0.5^{\circ}C$ water. The total length of the hatched larvae was $2.52{\sim}3.0\;mm$ (mean, $2.75{\pm}0.04\;mm$). At hatching, the larva, with the mouth and anus not opened yet, had yolk sack, $28{\sim}31$ myomeres and eyes with melanophore. Yolk completely 2 days after hatching and the total length of post-larvae $3.12{\sim}3.63\;mm$ (mean, $3.39{\pm}0.05\;mm$). At the 18 days after hatching, the tip of tail became curved at the end and the stems for pectoral, dorsal, and caudal fins appeared. Juveniles, having all firm rays, was $44.12{\sim}58.72\;mm$ (mean $55.95{\pm}6.74\;mm$) in TL 25 days after hatching.

• Korean Journal of Veterinary Service
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• v.27 no.3
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• pp.281-288
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• 2004

As all other intensively farmed domestic species, most mortality in ostriches is closely to rearing conditions. While ostriches is also highly sensitive to stress, species-specific infectious disease play only a minor role. But investigation of ostrich's disease is not peformed almost in Korea. The study was performed to investigate the titers of antibody for Newcastle disease(ND), Infectious bronchitis(IB), Egg drop syndrome '76(EDS), Avian influenza(AI), salmonellosis, Mycoplasma gallisepticum infection(MG), Mycoplasma synoviae infection(MS), Infectious bursal disease(IBD), Brucellosis, Toxoplasmosis, Japanese encephalitis(JE), Porcine parvovirus infection, Encephalomyocarditis and Porcine reproductive respiratory syndrome (PRRS). The results obtained in the 62 ostrich sera slaughtered in Gyeongbuk province were summarized as follows: The average of antibody positive rates to ND, IB, EDS, AI(H9Nl), JE, Porcine parvovirus infection and Encephalomyocarditis by HI test were $75.8\%,\;100\%,\;0\%,\;0\%,\;51.6\%,\;50\%\;and\;56.5\%$ respectively. The antibody positive rates to salmonellosis, MG, MS by plate agglutination test were $12.9\%,\;25.8\%,\;and\;0\%$ respectively. Antibodies to disease agent such as IBD and AI by agar gel precipitation(AGP) test, Brucellosis by tube agglutination, toxoplasmosis by latex agglutination test and PRRS by IFA were all negative.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.539-549
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• 2004

Mean death time of inoculated embryonated egg is one of the methods to determine the virulence of the Newcastle disease viruses (NDV). Evaluation of tissue tropism of NDV in the host has been proposed as an another way to determine the pathogenicity of NDV based on the principal site of viral replication. To evaluate the tissue tropism among NDV, an immunohistochemistry(IHC) technique using monoclonal antibody was applied in one-day-old SPF chickens inoculated with different ND vaccine strains such as Ulster 2C, VG/GA and B1 viruses by eye drop instillation. The tissues used for this comparison were trachea, intestine, Harderian gland and cecal tonsil, which were collected at 0.5, 1, 2, 3, 5, 8, 10, 14 days post inoculation. Among test groups, chickens inoculated with B1 viurs, which is known to replicate in the respiratory system, have IHC positive staining mainly in the trachea and those inoculated with Ulster 2C have IHC positive staining mainly in the intestine. However, chickens inoculated with VG/GA strain have IHC positive staining in both the trachea and intestine. Therefore, a differences in tissue tropism among ND vaccine strains has been proved by the IHC technique. Based on this results, the IHC staining technique could be used to classify the NDV or to study the pathogenesis of NDV in chickens.

• Korean Journal of Poultry Science
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• v.18 no.3
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• pp.151-159
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• 1991

As a part of investigation on causes of drop in egg production in domestic chicken breeding farm, bacteriological contamination on air, feed, drinking water and artificial insemination instruments of randomly selected three farms was surveyed. Total bacterial population in the air was very high in all of the chicken houses tested and was not significantly different among these farms . However, total bacterial counts in the air of the problem house having egg drop problem and colibacillosis was higher than normal house within the problem farm. Bacterial population in the assorted feed was low before or after administration on the normal farm while it was much more increased after administration than before administration on the problem farm. Bacterial population of the drinking water in the source of water supply was very low and has no differences among farms tested. Also, bacterial population in the normal farm was not significantly different between source of water supply and after administration. However, population of total bacteria and coliform bacteria after administration was increased. Bacterial population was much higher in the artificial insemination instrument of problem farm than normal farm. However, this bacterial population in the problem farm was decreased to those of normal farm after these instruments were sanitized.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.175-192
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• 1989

A total of 9, 012 cases was submitted for diagnosis of chicken diseases to Veterinary Research Institute, Rural Development Administration from domestic chicken farms during 18 years from 1971 to 1988. Of them, 6, 181 cases diagnosed as the infectious disease were investigated for the detection rate of infections on basis of you, season , and chicken age. The results obtained were summarized as followings：1. Detection rate or the infections was lowest as 49.3% in the year 1973, and highest as 78.6% in 1985 (average 68.6%). 2. Of infections detected, bacterial diseases were most frequent (32.6%), and followed in order by viral (26.3%), parasitic (7.7%), and fungal diseases (2.1%) in geneal. 3. The most frequently detected bacterial diseases in order of prevalence were mycoplasmosis (8.8%), colibacillosis (8.5%), and staphylococcosis (5.8%), and followed by salmonellosis pullorum disease , yolk sac disease, and salpingitis (0.8-1.5%). 4. In viral diseases, 7.5% of infections detected was lymphoid leukosis and 7.2%-Marek's disease, 4.4%-Newcastle disease, 2.0%-infectious laryngotracheitis, 1.7%-infectious bursal disease, and 1.0%-avian encephalomyelitis, while detection rate of infectious bronchitis, egg drop syndrome '76, and inclusion body hepatitis was less than 1.0%, respectively. 5. The most prevalent parasitic disease was coccidiosis (4.5%), followed by ascariasis (1.4%). The detection rate of other parasitic diseases including leucocytozoonosis, black head , heterakiasis, and ectoparasitosis was very as 0.2-0.7%, respectively： In fungal diseases, 2.0% of infections was detected as aspergillosis, and followed by candidiasis (0.1%). 6. Detection rate of the infections on basis of season was somewhat higher in summer. (27.7%), and autumn (27.7%) than in winter (23.5%), and spring (21.5%) in general. In bacterial, viral, and fungal diseases, there were the similar tendencies of detection rate as in infections, while parasitic diseases were much highly detected in summer (34.3%), and autumn (39.5%) than in any other season. 7. Among bacterial diseases colibacillosis was most frequently detected in summer, and staphylococcosis in autumn. In detection rate of viral diseases, Marek's disease, infectious laryngotracheitis, and infectious bursal disease was highest in summer, lymphold leukosis, fowl pox and egg drop syndrome '76 in autumn, and infectious trachitis in winter, repectively. The majority of important parasitic diseases including coccidiosis were highly detected in summer and autumn. 8. On basis of chicken age, detection rate of infections were highest in chicken of growing period between 30 and 150 days of age (41.4%), and followed by 35.3% in laying chicken over 150 days of age, and 17.3% in chicken of brooding age under 30 days of age. Bacterial, and parasitic diseases were most frequently detected in chicken of growing period, viral diseases in chicken of growing, and laying period as nearly equal rate of detection, and fungal diseases in chicken of brooding age.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.110-116
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• 2000

Duck viral hepatitis is an acutic, highly infectious viral disease of young ducklings. The most practical means for controlling duck viral hepatitis is the vaccination of ducklings or of a breeding stock. We attempted to develop a vaccine strain of duck hepatitis virus (DHV) using a Korean isolate by serial chicken embryo passages. The propagation of DHV in chicken embryos was carried 140 passages. After the $50^{th}$ passage, of which the virus was non-pathogenic for ducklings, approximately every $20^{th}$ passage of the virus was tested for vaccinal efficacy. Both the $70^{th}$ and $90^{th}$ passage of the virus gave good protection against challenge infection to a DHV-DRL reference strain(type 1) and a virulent Korean isolate. The $110^{th}$, $125^{th}$ and $140^{th}$ passage of the virus were less protective than the $70^{th}$ and $90^{th}$ passage, which means that more than $110^{th}$ passage may lead to over-attenuation of the virus. Ducklings vaccinated with the chicken-embryo-adapted virus by oral, intramuscular or eye drop administration showed earlier resistance to challenge infection from 3 to 7 days postvaccination. Of the above methods, ducklings vaccinated intramuscularly presented the most rapid resistance against challenge. The minimum immune dose of the chicken-embryo-adapted virus in ducklings was also studied. Ducklings inoculated with a dose of $10^{2.0}\;ELD_{50}$ and below were not fully protected against challenge with a virulent DHV, showing a protection rate of 67% to 73%, but ducklings inoculated with a dose of $10^{3.0}\;ELD_{50}$ and over were completely protected. The virus yield of the chicken-embryo-adapted DHV was examined at 24hrs and 48hrs of the incubation time in the allantoic fluid, embryo head and embryo minus head of the embryonating egg. In all three components, the titer of the virus was higher at 48 hours than that at 24 hours after incubation. And the titer of the virus was higher in the embryo minus head, embryo head and the allantoic fluid, in order. Field trials for evaluating the efficacy of the attenuated DHV as a live vaccine were done in duck farms with about 25% mortality of flocks resulting from duck viral hepatitis. After the use of the experimental vaccine, the mortality due to duck viral hepatitis was dramatically reduced in the farms. These results indicated that the attenuated DHV using a Korean isolate could be a good candidate as a live vaccine strain of DHV in Korea.

• Journal of The Korean Association For Science Education
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• v.32 no.5
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• pp.903-927
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• 2012

The study aimed to analyze middle school students construction of physics inquiry problems for open inquiry from the viewpoint of variable isolation and clarification, and investigate students' difficulties during the processes of variable isolation and clarification to get implications for teaching and learning strategies for small group open inquiry activities which have been included in the 2007 national curriculum. The participants were 4 students who had attended an outreach program for the science gifted run by a university institution located in Seoul area. They performed an open inquiry on egg drop for 13 lessons for 30 hours. Level descriptions for variable isolation and clarification have been developed and applied to analyze students' inquiry problems and variables included by the problems. Students iterated inquiry processed 5 times and the inquiry problem showed progress gradually. Dependent variables have been isolated ahead and the levels of variable isolation and clarification showed higher than the independent variables. Many kinds of independent variables isolated extensively and the independent variables and control variables have been mingled. One of the reasons why students had some difficulties in isolation of independent variables could be the absence of theoretical models. The realities of school lab could restrict the variable isolation and clarification as well as topic selections. Some sensory or extensive variables such as broken eggs and drop height seem to be salient to be focused on as core variables. Lack of background knowledges could be one of the reasons for students' difficulties in variable clarification, such as theoretical definitions and operational definitions. As a result of lacking background knowledges, students could not construct theoretical models even though they could isolate and clarify variables as scientific lexical definitions. Some perceptions of inquiry as trial and error or reckless establishment of causal relations between variables could be accounted as one reason.

• Korean Journal of Poultry Science
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• v.36 no.2
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• pp.165-175
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• 2009

Fatty liver-hemorrhagic syndrome (FLHS) is a common nutritional disease in commercial layers and breeders. The most important clinical sign of FLHS is a sudden drop in egg production and increased mortality which causes significant economic loss in the poultry industry. However, the current diagnostic method for FLHS is based on the gross findings at necropsy which is not helpful to reduce the economic loss because of lateness of diagnosis. Therefore, we need early diagnosis and diagnostic methods before chickens were affected by FLHS. In this study we tried to evaluate the effectiveness of clinical pathology including blood chemistry as an early diagnostic method for FLHS in commercial chickens. Profiles of blood biochemistry were compared between two flocks selected in the same commercial layer farm based on the presence of FLHS clinical sings. A flock with clinical signs of FLHS was designated as FLHS and other flock without clinical signs of FLHS as Non-FLHS. Several parameters of blood biochemistry were selected and compared between FLHS and Non-FLHS to evaluate the possibility of early diagnosis. Average concentrations of serum cholesterol, serum calcium, aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and creatine kinase (CK) were $139.4\;{\pm}\;87.2$ (mg/dL), $24.5\;{\pm}\;5.4$ (mg/dL), $153.6\;{\pm}\;23.1$ (IU/L), $1238.3\;{\pm}\;475.2$ (IU/L) and $1107.3\;{\pm}\;422.8$ (IU/L) in Non-FLHS flock, respectively, and $210.2\;{\pm}\;173.2$ (mg/dL), $25.2\;{\pm}\;4.1$ (mg/dL), $174.3\;{\pm}\;53.5$ (IU/L), $1694.9\;{\pm}\;691.3$ (IU/L) and $1104.9\;{\pm}\;472.9$ (IU/L) in FLHS flock, respectively. The activities of serum cholesterol, AST and LDH except CK, were significantly higher in FLHS than those in Non-FLHS flock (p<0.05). Some birds of FLHS flock showed 2~17 times greater than in Non-FLHS flock. For the definitive diagnosis of FLHS in the flocks tested for blood chemistry, we analyzed fat content and histological lesion score in the liver sampled from both FLHS and Non-FLHS flock. Average liver fat contents based on dry weight were $16.1\;{\pm}\;0.4$ (%) in Non-FLHS flock and were $21.6\;{\pm}\;16.0$ (%) in FLHS flock. These result confirmed that FLHS flock was definitely affected by FLHS. The above results suggest that selected parameters of blood biochemistry, particularly AST, could be useful to diagnose FLHS before significant liver damage occurred in commercial layers.

• Korean Journal of Animal Reproduction
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• v.25 no.2
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• pp.163-169
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• 2001

OSBA(oocytes-sperm binding assay) is a tool developed for rapid test of optimal condition of IVF medium and protein source by binding ability of mouse sperm and egg. Mouse oocyte-cumulus complexes were prepared by removing of the cumulus cells with 0.1% hyaluronidase. 10$\pm$2 oocytes per 30 ${mu}ell$ medium drop were inseminated with 3 ${mu}ell$ sperm suspension and were cultured f3r 3 hours and 24 hours, respectively. And the oocytes were recovered gently and the No. of sperm bound on oocytes were counted. In the Exp. 1, the ratio of oocytes bound with one sperm at least were 60.2%(50/83), 2%(2/77) and 100%(79/79) in the medium with no protein, FBS(15%, v/v) and BSA(0.4%. w/v), respectively, Fetal bovine serum(FBS) seriously inhibited sperm binding on oocyte, although bovine serum albumin(BSA) promoted the binding ability. The inhibiting effect of FBS was dependent on the concentration of FBS. The sperm binding ability according to oocyte maturity was tested in the Exp. 2. There was no significant difference between Met. II (mature) and Met. I (intermediate mature) oocytes in the number of oocytes bound with sperm and the number of sperm bound on oocytes. Finally, in Exp. 3, two batches of Ham's F10 medium with good and poor quality by OSBA were tested (The ratios of embryos developed from PN 1-cell stage to hatched blastocyst; 25% vs. 70%). In the medium with good quality, sperm binding ability was significantly increased (P ＜ 0.05). The ratio of oocytes bound with one sperm at least was 66% and 90% in the medium with poor and good quality, respectively. Conclusively, It was possible to test IVF medium condition rapidly and easily by OSBA.