• Asian-Australasian Journal of Animal Sciences
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• v.19 no.7
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• pp.1047-1053
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• 2006

The current study was designed to determine the effects of dietary docosahexaenoic acid (DHA) on fatty acid deposition in egg yolk and various tissues of laying Tsaiya ducks, and on the mRNA concentrations of hepatic lipogenesis-related transcription factors. Thirty laying ducks were randomly assigned to three treatments with diets based on corn-soybean meal (ME: 2803 kcal/kg; CP: 17.1%; Ca: 3.4%) supplemented with 0% (control diet), 0.5% or 2% algal DHA oil. The DHA content in egg yolks of the ducks was elevated significantly (p<0.01) with the supplementation of dietary DHA. The DHA percentage of the total fatty acids in the egg yolk of laying ducks was 0.5%, 1.3% and 3.4% for 0%, 0.5% and 2% algal DHA oil treatments, respectively, for the $1^{st}$ week, and 0.5%, 1.5% and 3.3% for the $2^{nd}$ week. Therefore, algal DHA oil can be utilized by laying Tsaiya ducks to enhance the egg-yolk DHA content. The concentrations of triacylglycerol (TG) and cholesterol in plasma of laying Tsaiya ducks were not affected by dietary DHA treatments (p>0.05). The DHA concentration in plasma, liver, and skeletal muscle was increased with the addition of dietary algal DHA oil (p<0.05). The mRNA abundance of sterol regulatory element binding protein 1 (SREBP1) and SREBP2 in the livers of laying Tsaiya ducks was not affected by dietary DHA, suggesting that the expression of these transcription factors is tightly controlled and not sensitive to DHA treatments.

• Journal of Nutrition and Health
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• v.47 no.6
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• pp.385-393
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• 2014

Purpose: The aim of this study is to examine the effects of egg consumption and suggest proper guidelines for consumption of eggs by determining the relationship between eggs and cholesterol. Methods: Literature review was conducted on the relationship between nutritional, functional properties of eggs and serum cholesterol, as well as cardiovascular disease. Results: Eggs, which are a good protein food with complete amino acid composition, contain vitamin A, riboflavin, vitamin $B1_2$, folic acid, vitamin D, vitamin E, vitamin K, calcium, iron, choline, selenium, ${\beta}$-carotene, lutein, zeaxanthin, etc. However the egg yolk has a high cholesterol content, which is associated with chronic diseases, including heart disease and hypertension. As a result, its intake is subject to regulation. Outbreak of heart disease by yolk intake can show different results depending on the characteristics of the subjects, amount of egg intake, and the implications of other foods eaten. It is difficult to determine whether eggs are beneficial, as they are the main supplying source for other major nutritive elements as well. Several research studies insist that when cholesterol intake increases by 100 mg, the level of serum cholesterol increases by 2.2~4.5 mg/dL and when serum cholesterol increases by 1%, the risk of heart disease increases by 2%. This indicates that a large intake of eggs can increase the risk of heart disease. Although the cholesterol of egg yolk and serum cholesterol are correlated, it is insufficient to conclude that only cholesterol and not other components are related to heart disease. In fact, other components in egg such as various unsaturated fatty acids and phospholipids could be related as well. Rather than concluding egg as a 'good' or 'bad' food according to its cholesterol content, it is important to define egg as a part of dietary patterns. Conclusion: Generalizing an indiscriminate and uniform amount of egg intake for all seems inadequate. However, patients with diabetes or heart disease should pay particular attention to the amount of egg intake. As for the norm, eating egg with vegetables as a substitute for other animal products seems beneficial.

• Food Science of Animal Resources
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• v.32 no.2
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• pp.162-167
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• 2012

Phosvitin was extracted from a chicken egg yolk and the iron-binding, along with antioxidative activity of the extracted phosvitin, was determined after mixing with ground beef at the concentrations of 100 and 500 mg/kg of meat. The electrophoretic pattern of the extracted phosvitin on SDS-PAGE was found to be identical to that of the standard phosvitin. The extracted phosvitin at $1,000{\mu}g$/mL showed an ability to bind approximately 65% of the iron in a 3 mM iron solution. Lipid oxidation was inhibited in the ground beef mixed with 500 mg/kg of the extracted phosvitin, during storage at $4^{\circ}C$ compared to that of the control (p<0.05). Additionally, color stability of ground beef containing the extracted phosvitin was enhanced (p<0.05). The pH, cooking loss, texture, and sensory properties of the ground beef were not affected, by adding up to 500 mg/kg of the extracted phosvitin. This result suggests that the phosvitin extracted from egg yolk could be used as an antioxidant reagent. In particular, phosvitin would be more amenable for use in meat products because it is a natural protein derived from animal products.

• Animal Bioscience
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• v.34 no.2
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• pp.256-264
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• 2021

Objective: The purpose of this experiment was to investigate the effects of the Agaricus bisporus stem residue (ABSR) on the performance, nutrients digestibility, antioxidant activity of laying hens, and its effects on egg storage to determine the appropriate dosage of ABSR, so as to provide a scientific basis for the effective utilization of ABSR. Methods: A total of 384 53-wk-old Nongda III layers were randomly divided into six treatments, four replicates in each treatment and 16 birds in each replicate. The control treatment was fed with basic diet, while experimental treatments were fed with diets of 2%, 4%, 6%, 8%, and 10% ABSR respectively. The experimental period was 56 d. Results: The results showed that compared with the control treatment, ABSR had no significant effect on laying performance (p>0.05). The crude protein and total energy digestibility of experimental treatments was significantly higher than those of control treatment (p<0.05). When eggs were stored for 1 wk, 2 wk, and 3 wk at 25℃, there were no significant differences in egg storage between the experimental treatments and the control treatment (p>0.05). The superoxide dismutase (SOD) activity and glutathione peroxidase (GSH-Px) activity in the serum of the experimental treatments were significantly higher than those of the control treatment (p<0.05), and the malonaldehyde (MDA) content did not change dramatically. SOD activity in yolk of experimental treatments was significantly higher than that in control treatment (p<0.05); MDA content in yolk was markedly lower than that in control treatment (p<0.05). The activity of GSH-Px and SOD in yolk of experimental treatments was significantly higher than that of control treatment stored at 25℃ for 21 d, and the content of MDA was significantly lower than that of control treatment (p<0.05). Conclusion: ABSR can be used to improve the antioxidant activity of laying hens without affecting laying performance.

• Journal of Nutrition and Health
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• v.31 no.3
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• pp.243-252
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• 1998

This study was conducted to investigated the short-term effects of early weaning and protein intake on organ and cell growth, nitrogen metabolism and physiological functions of rats. Five groups of early weaned rats separated from the dam on the 15th day postpartum were each given one five diets consisting of either one of the three levels of casein-low(8%), -normal (16%), and -high(32%), or a normal level (16%) of isolated soy protein(ISP) or egg yolk protein, for 7 days. The normal weaned rats were fed maternal breast milk for three weeks from birth. On the 22nd day postpartum , all the rats were sacrificed . The weight gain of the early weaned rats, especially the ones fed high protein, was observed to be significantly lower than that of the normal weaned rats. By the 15th day, of early weaning and especially in the ISP-fed rats, the total DNA contents of liver and kidney, which may be said to represent an index of cell numbers, significantly decreased, but their fresh and dry weight and protein/DNA ratio, allegedly representing an index of cell size, significantly increased , not affecting the cell number and cell size of brain. There were no differences in total serum protein and albumin concentrations between early and normal weaned rats. In the early weaned rats observed , the serum urea N and $\alpha$-amino N concentrations significantly increased in high protein-fed rats, and decreased in low protein-fed rats. Another observation was that no significant difference was noticed as regards to serum GOT activity, total bilirubin, uric acid, and creatinine concentration, which may represent indices of liver and kidney functions, among rat groups, GPT activity was an exception . These results suggest that premature weaning and the quality and quantity of dietary protein significantly affect organ and cell growth and nitrogen metabolism but does not seriously affect physiological functions in the neonatal development of rats.

• Korean Journal of Poultry Science
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• v.51 no.2
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• pp.27-37
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• 2024

The poultry plays a crucial role in the animal industry, providing humans with efficient, high-quality animal protein. The rapid growth and short generational intervals of broilers offer significant benefits compared to other economic animals. This growth and increased muscle mass in modern commercial broilers result from advancements in breeding. However, the high productivity of contemporary broilers indicates they are approaching their physiological limits, with excessive fat accumulation becoming a significant industry issue. This not only reduces lean meat yield and feed efficiency but also negatively impacts consumers, especially due to problematic abdominal fat, which consumes more energy than lean meat production. Laying hens, reared for extended periods, maintain high productivity, producing a substantial number of eggs. This productivity in laying hens, akin to broilers, stems from genetic selection and breeding. For egg production, laying hens require physiological support for necessary nutrients. In this context, yolk fat accumulation is a critical physiological process. Lipoproteins, essential in avian lipid metabolism, are vital for yolk and body fat accumulation. Understanding these lipoproteins and their metabolism is key to developing healthier, more productive animals, offering economic benefits to farmers and improved nutritional quality to consumers. This review focuses on the physiological aspects of dietary fat transport, fatty acid biosynthesis in the liver, fat accumulation in the abdomen and muscles, and lipid deposition in egg yolks in chickens. It also highlights recent research trends in the regulation of fat metabolism in poultry.

• The Korean Journal of Zoology
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• v.30 no.1
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• pp.10-28
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• 1987

Changes of protein synthesis in the isolated egg chambers were studied during oogenesis of Drosophila melanogaster. Protein synthesis did not change much in quantity except that the activity was slightly enhanced at the stages 11 and 12, when new structures such as vitelline membranes and yolk granules were made, but considerably changed in quality during oogenesis. Protein synthesis was believed to occur mainly in the follicle cells, and a number of stage-specific proteins were found to differ at various stages. The observations suggest that proteins synthesized in the cells within chambers as well as those from the outside of the chambers might be directly required for the growth and maturation of oocytes in Drosophila.

• The Korean Journal of Zoology
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• v.26 no.4
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• pp.283-294
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• 1983

In order to study the change of protein synthesis in developing chick embryo under the influence of carcinogenic substances, we introduced a kind of potent carcinogen, 4-nitroquinoline-1-oxide (4 NQO) to the yolk sac of developing chick embryo. There are changes of synthetic pattern of protein abreast with proceeding of development is each tissue. Protein synthesis in samples which was treated with 4NQO was decreased as compared with untreated control samples. There are tissue specificity in 4NQO effect, showing the apparent decreasing at the 24 hr after drug treatment in the lung and gizzard muscle but not in heart muscle. The results in the present study suggested that 4NQO treated samples was decreased as compared with control samples. From the above data we could know that 4NQO also affected the synthesis of glycosaminoglycan.

• The Korean Journal of Zoology
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• v.28 no.4
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• pp.257-278
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• 1985

The effect of aromatic amino acids such as phenylalaine, tryptophan and tyrosine on somitogenesis at the early stage of chick embryo has been investigated morphologically using light and electron microscopy. Micrographs of aromatic amino acid injected chick embryo showed that an incomplete somite segmentation occurred and some decremental effect on the nervous system were observed. Somites were poorly developed and their size were variable. Electron micrograph of somatic cells from aromatic amino acid injected chick embryo showed that chromatins were coagulated, some of mitochondria were damaged, and nucleus were transformed considerably in some cases. The protein and nucleic acid levels and some enzyme activities of 15-day chick embryo which received the injection of 1mg of aromatic amino acid in 0.05 ml of saline 24 hours after the incubation were analyzed. Protein, DNA and RNA levels of the test group were not lowered significantly but the activities of enzymes for basic metabolism, such as lactate dehydrogenase, succinate dehydrogenase, malate dehydrogenase and glucose 6-phosphate dehydrogenase were considerably lowered as compared with those of control. From the present expeerimental results, it was tentatively suggested that the administration of amino acid might slow down the yolk granule degradation probably by feed back mechanism resulting in the disturbance of amino acid balance in the cell, which might give rise to impair normal metabolic pattern leading to abnormal somitogenesis to chick embryo at very early stage of development.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.277-286
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• 2001

Improvement and possible commercialization of a home-made electroporation apparatus(home-made) were further tried to establish a simple and effective introduction of foreign gene into sperm followed by in vitro fertilization. Expressions of introduced pJJ9 and pNT plasmids were shown in all fertilized eggs with electroporated spermatozoa. In particular, with this gene transfer system all the fry showed a consistently transient expression in the syncytium of the yolk sac. This fact is important since some required, minute quantity of human proteins can be produced from the established transient expression on the yolk sac of all fry derived from in vitro fertilization with electroporated spermatozoa. To explore tissue-specific expression in fish, which we will use a similar system later, we targeted the nerve tissue to see whether tissue-specific promoter is working in fish properly. pNT plasmid containing a nerve cell-specific tubulin promoter gene demonstrated consistently exact targeted expressions among the developing nerve cells in later stages of embryos and hatched fry. Finally, liver-specific genes are now being cloned by using already selected primers for useful human protein gene fusion.