• Asian-Australasian Journal of Animal Sciences
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• v.11 no.6
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• pp.713-717
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• 1998

The synergistic effect of fetal calf serum (FCS) and chicken embryo extract (CEE) on protein synthesis of chicken embryo myoblasts was examined. Myoblasts were derived from chicken embryo cultured for 14 days by trypsin digestion and cultured in 5% $CO^2/95%$ air at $37^{\circ}C$. When myoblasts were cultured at the low level of cell density (20-50% of well), CEE enhanced the ability of FCS to stimulate protein synthesis of myoblasts. However, there was no significant effect of CEE to stimulate protein synthesis of myoblasts cultured at high level of cell density (100% of well).

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.336-342
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• 2009

Avian embryos at high altitude are independent of maternal protection against hypoxia, which is contrary to mammals. It is well known that chronic hypoxic exposure at key points can significantly impact on avian development. Tibetan Chicken, a Chinese indigenous breed, living in Tibetan areas with an altitude of 2.2 to 4.1 thousand meters, has an adaptive mechanism to hypoxia. In the present study, fertilized eggs of Tibetan Chicken were incubated under 13% and 21% oxygen concentration. Two lowland chicken breeds, Shouguang Chicken, an indigenous chicken breed in Shandong Province of China, and Dwarf Recessive White Chicken, an imported breed in Beijing, were used as control groups. The embryo mass and some organs such as brain, heart, liver, stomach and eye weight in the three species were measured at Hamburger-Hamilton stage 39, 41, 43 and 45 under hypoxic and normal conditions. The results showed that in hypoxia Tibetan Chicken significantly differed from the two lowland chicken breeds in embryo mass at Hamburger-Hamilton stage 41, 43 and 45 (p<0.01). In particular, Dwarf Recessive White Chicken and Shouguang Chicken showed retarded growth in hypoxic incubation (p<0.01), whereas Tibetan Chicken showed no significant difference between hypoxic and normal conditions (p>0.05). In addition, heart and the other organs showed different susceptibility to hypoxia at the studied stages. In conclusion, chronic hypoxia induced a change in the embryo development of the three different species and Tibetan Chicken showed adaptation to hypoxia. Of note, the embryo developmental physiology of Tibetan Chicken in response to hypoxia will shed light on the process of physiological acclimation or evolutionary adaptation as well as the study of clinical disease.

• Journal of Embryo Transfer
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• v.33 no.1
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• pp.31-40
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• 2018

Developmental aspects of chicken embryos showed dramatic difference compared with those of mammals and consequently, such difference in various developmental events leads to different feasibility in both clinical and industrial application. We have concentrated on the studies for using of chicken bone marrow cells and currently we found number of unique cellular properties. Through this article, we reviewed characteristics and cell signaling of osteogenic cells during endochondral ossification in chicken long bone.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.2
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• pp.319-323
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• 1993

The effect of bovine growth hormone digested with trypsin on whole-body protein synthesis in vitro of chicken embryos was investigated by using a whole-embryo culture system. Bovine growth hormone at 5.3 and 530 ng/ml was digested partially and completely with trypsin for 4 min and 18 h, respectively. After culturing chicken embryos with a synthetic medium containing $L-[4-^3H]$ pheylalanine, whole-embryo protein synthesis was determined from the ratio of specific radioactivities of free and protein-bound pheylalanine. Whole-embryo protein synthesis of the control group cultured with no bovine growth hormone was $49.5{\pm}2.2%/d$. There was no significant interaction between digestion time and the concentration of trypsin-digested bovine growth hormone. Tryptic digestion of bovine growth hormone increased fractional synthesis rates of whole-body protein compared to the 0-min groups, and there was no significant difference between the 4-min and 18-h groups. The higher concentration (530 ng/ml) of trypsin-digested bovine growth hormone was more effective in enhancing whole-embryo protein synthesis than the lower concentration (5.3 ng/ml).

• Applied Microscopy
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• v.26 no.2
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• pp.123-136
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• 1996

To investigate the effect of aflatoxin $B_1$, on survival rate and ultrastructure of liver during chick embryogenesis electron microscopic methods were used. After injection of aflatoxin $B_1$ into the yolk, ultrastructural changes in the liver of chicken embryo were observed. The results were as followed. 1. 12-day old chicken embryos were treated with single injection of aflatoxin $B_1$ with the dose of $0.0005{\mu}g,\;0.005{\mu}g,\;0.05{\mu}g,\;0.5{\mu}g,\;2.5{\mu}g,\;5.0{\mu}g$ each. Chicken embryos treated with the dose of $0.5{\mu}g$ of aflatoxin $B_1$ had survival rate of 22%. The embryos treated with $2.5{\mu}g$ of aflatoxin $B_1$ hardly survived. 2. Chicken embryos treated with $0.05{\mu}g$ of afatoxin $B_1$ had hatched in 30%, but once hatched, they all survived. 3. After administration of $0.05{\mu}g$ of aflatoxin $B_1$ into the 12-day old chicken embryo, the electron microscopic studies were examined during development stages. The nuclei of hapatocytes became irregularly shaped and the structures of endoplasmic reticulum were changed to spherical types at 20-day old chicken embryo. Also, mitochondria became to be dilated and severe fibrosis was induced in the cytoplasm. However, the hepatocytes became almost normal in 30-day old young chicken.

• Korean Journal of Poultry Science
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• v.32 no.4
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• pp.225-229
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• 2005

Microinjection of recombinant retrovirus beneath the blastoderm of non-incubated chicken embryo is now the most widespread method for generating transgenic chickens, but transgenesis rates are very low. So to improve this problem, we first introduced retrovirus vector carrying RSV-GFP gene to an one-cell embryo culture system. To investigate whether retrovirus could work on an one-cell chicken embryo, we microinjected the concentrated retrovirus stocks into the germinal disc of one cell or stage-X chicken embryos. Analysis of reporter gene expression on day 4 embryos showed that GFP expression was observed in the only stage-X chicken embryo but was not in the one-cell embryo group. These results suggest that retrovirus system is the most efficient method to generate transgenic chickens in the stage-X embryo.

• Asian-Australasian Journal of Animal Sciences
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• v.6 no.4
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• pp.581-589
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• 1993

A plasmid vector, $RSVLTR/{\beta}G2$, containing lacZ gene under the control of the RSVLTR promoter were transfected into chicken embryo fibroblasts by three different transfection methods. Calcium phosphate, lipsome and DEAE-dextran techniques were applied for transfection of chicken cells. A histochemical assay with X-gal was used as a simple method for screening transfected cells. Plasmid $RSVLTR/{\beta}G2$ was expressed proficiently in the chicken embryo fibroblast. Calcium phosphate-DNA precipitate transfection resulted in the highest efficiency for transient expression of $RSVLTR/{\beta}G2$. Transfected cells formed colonies on the 9th day of incubation indicating stable transformation of the inserted plasmid.

• YAKHAK HOEJI
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• v.33 no.1
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• pp.39-45
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• 1989

Effects of dammarane glycosides of Panax ginseng on primary cultured chicken embryonic brain cells were studied by microscopic observation and determination of the activity of pyruvate dehydrogenase complex (PDHC). Brain cells were prepared from the brain of 10-day-old chicken embryo and cultured with either a standard medium consisted of 85% Dulbecco's Modified Eagle Medium (DMEM), 10% horse serum and 5% chicken embryonic extracts or a deficient medium consisted of 90% DMEM and 10% horse serum. It was observed that dammarane glycosides of Panax ginseng seemed to show the tendency to stimulate the neurite outgrowth of brain cells which were cultured with a deficient medium under microscopic observation. The activity of PDHC in brain cells cultured with a deficient medium was increased by dammarane glycosides of Panax ginseng.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.1
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• pp.17-20
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• 2001

The effect of chicken IGF-I on protein synthesis of chicken embryo myoblasts cultured in serum-free medium was examined. When myoblasts were expanded to approximate 20-30% of well, the medium was changed to the serum-free medium including 0, 2, 20, 200 or 2000 ng/ml of recombinant chicken IGF-I. The culture medium including 10% fetal calf serum (FCS) was used as positive control. After 1 day of incubation, protein synthesis was measured by the incorporation of [$^3H$]-L-leucine. Thereafter cells were continued to incubate for further 18 hours, and the radioactivity in the protein was measured as an index of protein synthesis. The values for protein synthesis cultured in the serum-free medium without chicken IGF-I or with 2000 ng/ml of chicken IGF-I were the lowest. Protein synthesis was elevated with increasing chicken IGF-I concentration from 0 to 20 ng/ml. The values for protein synthesis in the 20 ng/ml and 200 ng/ml IGF-I groups were about half of that of the FCS group. The present study revealed that the potency of chicken IGF-I at the levels of 20 to 200 ng/ml to stimulate myoblast protein synthesis was about half of that of 10% FCS.

• 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.