• Korean Journal of Poultry Science
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• v.46 no.3
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• pp.205-213
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• 2019

The objective of this experiment was to investigate the effect of dietary apparent metabolizable energy and protein concentrations on growth performance, carcass characteristics, and nutrient digestibility of Korean native ducks. In $2{\times}2$ factorial arrangement, 1-d-old Korean native ducks were completely randomized to experimental diets with 2,800 and 2,900 kcal of AMEn/kgofdiet, respectively, from 0 to 21 d of age. From 22 to 56 d of age, experimental diets 3,000 and 3,100 kcal of, and contained 16% and 17% CP, respectively. Feed and water were provided ad libitum. And BW gain were higher during 0 to 21 d (P<0.01) in AME 2,800 kcal/kg and CP 21% diet treatment than other treatments. As AME increased from 2,800 to 2,900 kcal/kg, feed intake was decreased (P<0.05) during 0 to 21 d. From 22 to 56 d of age, the, BW gain, feed intake and were not different among the treatments. Carcass ratio, relative weight per 100 of BW (wing, back, neck, breast, and leg), nutrient digestibility, meat color and nutrient composition in breast meat the treatments. In conclusion, diets with 2,800 kcal of AME/kg and 21% CP or with 3,000 kcal of AME/kg and 17% CP at 0 to 21 d and 22 to 56 d, respectively, were more efficient.

• Journal of Animal Science and Technology
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• v.54 no.5
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• pp.369-373
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• 2012

AMP-activated protein kinase (AMPK) maintains energy homeostasis in skeletal muscle. Nonetheless, its functional role on protein synthesis with different nutrient availability has not been elucidated. Therefore, the purpose of this study is to examine the effect of AMPK activity on protein content in C2C12 myotubes incubated with low (5 mM; LG) or high (25 mM; HG) glucose media. LG stimulated (p<0.05) AMPK and acetyl CoA carboxylase (ACC) activity compare to those in HG group. Total protein content was higher in myotubes cultured with HG than in those cultured with LG and further increased by AICAR (5-amino-1-${\beta}$-D-ribofuranosyl-imidazole-4-carboxamide). Myotubes cultured with HG showed 7.5% lower UbFL (Ubiquitin Firefly Luciferase)-to-SV40 (Simian virus40) ratio compared to those in LG. Glucose level did not change the phosphorylation level of mammalian target of rapamycin (mTOR). Interestingly, administration of AICAR significantly increased phosphorylation level of mTOR in myotubes cultured with LG but not in those with HG. Overall, this data indicate that AMPK activity and protein turnover are finely regulated in response to different glucose concentration.

• Korean Journal of Poultry Science
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• v.30 no.2
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• pp.101-106
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• 2003

In order to study the optimum daily protein allowance for broiler breeders of 24 to 64 weeks of age on a control-fed basis, an experiment was carried out with 400 hens of Arbor Acres strain. Four levels of protein allowances were used to supply 18 to 24g of protein per day in 2g increments. As the age of hens increased, a same stepwise increase and decrease in daily energy allotment was used in all treatments. Same amount of calcium, phosphorus, methionine and lysine were supplied in all treatments and throughout laying period. Hen-day egg production was highest in hens receiving 20g protein per day(p<0.05), but there was no significant difference among those fed daily protein ranging 18 to 22g, and increasing the daily protein allotment up to 24g resulted in a significant decrease(p<0.05). Average egg weight showed a trend to increase as the daily protein allowance increase(p<0.05), but no significant difference was found among the hens fed daily protein 20 to 24g. Feed and ME conversion was superior in hens receiving 20g daily protein(p<0.05). CP conversion was increased as the daily protein allowance increase(p<0.05), but there was no significant difference between hens receiving 18 and 20g daily protein. Feed cost required per egg or per kg egg was lowest in hens fed 20g daily protein. It could be concluded that the optimum daily protein allowance was 20g in all performances.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.246-253
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• 1997

This study was conducted to investigate the effect of protein kinds and levels on lipid metabolism in hypercholesterolemia rats. Male Sprague Dawley rats were administrated 1% cholesterol and 0.25% sodium cholate to induce hypercholesterolemia and were fed on diet containing two levels(7, 20%) of casein and soy protein respectively. The rats were sacrified after 5 weeks of feeding periods. Total lipid content in serum was decreased in proportion to level of protein and soy protein was more effective than casein in lipid-lowering effect. Serum triglyceride content was significantly decreased in proportion to level of protein and did not show significance by protein kind. Serum phospholipid content was more significantly decreased in 20% protein groups than that of 7% protein groups. Total cholesterol content in serum was significantly decreased by protein and were decreased in proportion to level of soy protein. Free cholesterol content did not show significance by protein level. The degree of decrease predominated in soy protein groups. Serum HDL-cholesterol content and RL-cholesterol were increased in proportion to level of protein and effect of soy protein was not more significantly than that of casein. Atherogenic index was significantly decreased in proportion to level of protein and soy protein groups were more effective. Serum LDL-, VLDL-cholesterol contents were more significantly decreased in 20% protein groups than that of 7% protein groups. Serum $\beta$-lipoprotein and chylomicrone-cholesterol contents also showed significantly decrease by soy protein.

• Korean Journal of Poultry Science
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• v.43 no.4
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• pp.219-228
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• 2016

A total of 720 slow-growing Korean meat-type (Hanhyop 3) chicken were used to evaluate the effect of stocking densities and dietary protein levels on growth performance, meat quality, bone mineral composition, and serum corticosterone. Three (6.3, 9.5, and $12.6birds/m^2$) stocking densities and two dietary protein levels (19% and 18%) were factorially ($3{\times}2$) arranged for six treatments. Overall body weight gain (BWG) was highest (p<0.001) at the lowest stocking density ($6.3birds/m^2$). The feed intake (FI) of birds at the highest density ($12.6birds/m^2$) was lower than that of birds at the other densities, but resulted in better feed/gain (F/G). Among 18% protein groups, the overall FI of birds at $9.5birds/m^2$ was higher than that at the lowest density; therefore, birds at $9.5birds/m^2$ had poorer F/G than birds at the lowest density during days 61~75. Difference in F/G among densities was only significant (p<0.05) during days 61~75 but not significant (p>0.05) during days 41~60. Although there were no significant differences (p>0.05) in BWG and F/G between 19% and 18% dietary protein levels, FI of the 18% protein diet was less (p<0.05) than that of the 19% diet. Although there was no difference (p>0.05) in meat TBARS values, meat color differed (p<0.05) with stocking density and dietary protein levels. There was no effect (p>0.05) of stocking density and dietary protein levels on bone mineral composition. Serum corticosterone concentration increased (p<0.05) with increasing stock density but was not affected (p>0.05) by dietary protein levels. This study indicated that a density of $12.6birds/m^2$ is not recommended for slow-growing chickens. Between 19% and 18% dietary protein levels, 18% would be recommended for the Korean Hanhyop 3 chicken in the finishing stage.

• Journal of Nutrition and Health
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• v.21 no.1
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• pp.36-46
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• 1988

This study was carried out to investigate the effects of different protein and fat levels on the growth and on immune response in rats. In experiment 1, Sprague-Dawly male rats were fed diets containing 6%, 15%, or 30% casein with 2 levels of fat(2% and 30%) at each protein level. In experiment 2 and 3, rats were devided into 8 diet groups ; 4 different sources of proteins(casein, meat protein, fish protein, and gluten) were used at 15% level of the diet with 2% or 30% of dietary fat. The results show as follows 1) The rats in 6% casein group showed lower body weight gain and organ weight than those in 15% and 30% casein groups. There was no significant difference between 15% and 30% casein groups. In experiment 2, the gluten diet group showed the lowest growth rate and epididymal fat pad weight among 4 different dietary protein groups regardless the level of dietary fat. 2) There was no significant difference in immune response according to the sources and levels of dietary protein. However, the rats fed high fat diet showed the lower plaque-forming cell response than those fed low fat diet regardless dietary protein.

• Korean Journal of Poultry Science
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• v.16 no.3
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• pp.139-147
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• 1989

An experiment was carried out to investigate the effects of dietary energy levels and protein feeding systems on the performance of laying hens. Total 960 White Leghorn pullets were alloted in 10 treatments consisted of 1 metabolizable energy levels (2,900 and 2,600 kcal/kg) and 5 protein feeding systems (17-17-15%, 17-15-13%, 15-15-15%15-15-13% and 15-13-13% in phase I, II and/or III, respectively) from 20 to 80 weeks or age. As metabolizable energy level increased from 2,600 to 2.900 kcal/kg of diet, e99 Productions in phase I and II were not different but decreased in phase III. Egg weight was not different, but daily feed intake and viability were decreased in phase I, II and III. Feed conversions in phase I and II were improved but in phase III it was not different. On the other hand, as dietary Protein level increased from 13 to 17%, egg production and egg weight were increased, and feed conversion was improved , but daily feed intake and viability were not affected by the dietary protein level. For the laying period of 60 weeks, metabolizable energy level of 2,600 kcal/kg of diet and 17, 15 and 13% dietary protein levels in phase I, II and III, respectively, were considered to be adequate to support the optimum productivity.

• Proceedings of the Korean Society of Life Science Conference
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• 2000.12a
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• pp.39-43
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• 2000

HBV는 인체에 감염하여 간염, 간경변 및 간암을 유발하는 hepadnaviruses의 일종으로써 임상적으로 매우 중요한 바이러스이다. 그러나 이 바이러스에 의한 간암(HCC)의 발생 메커니즘은 아직 불확실하다. 최근에는 HBV의 X 단백질(HBx)이 간암 발생에 중요한 역할을 수행하는 것으로 보고되고 있다. HBx 단백질은 전사 활성인자(transcriptional activator)로써 숙주세포의 유전자발현에 영향을 미치어 세포증식 및 분화에 영향을 줄 수 있다. 본 연구에서는 HBx 단백질이 NIH 3T3 cell의 증식 및 형질전환에 미치는 영향을 조사하였다. HBx 단백질을 발현하는 세포주는 정상세포에 비하여 증식 속도가 2배 정도 빠르며, soft agar assay 결과에 의하면 대조군과 비교하여 더 많은 수의 colony를 형성하였다. 또한, 이들 HBx 발현 세포들은 접촉 저해 능력을 상실하여 HBx가 세포 형질 전환 능력을 가짐을 알수 있다 또한 HBx 발현 세포주에 있어서 p21의 RNA 및 protein수준이 정상세포에 비하여 낮으므로 HBx에 의한 증식 촉진 및 세포 형질 전환이 p21을 매개하여 이루어 짐을 알 수 있었다. HBx에 의한 p21 유전자의 발현 감소는 p21의 전사 수준에서 이루어지며 이는 p53-비의존적 경로에 의하여 이루어졌다.

• Journal of the Korean Society of Food Science and Nutrition
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• v.18 no.4
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• pp.389-397
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• 1989

This study was designed to investigate the effects of dietary protein level on Pb, Fe, and Cu accumulation of the tissue of the Pb-administered rats. The dietary protein levels were 6% 15%, and 40% and the lead-exposed rats were given 2,000 ppm-Pb drinking water solution. After 3 weeks, half of the each group rats were sacrificed and the rest were sacrificed 4 weeks later. Hematocrit, hemoglobin, R8C content in blood were lower in Pb-administered groups than in Pb-free group. Protein levels of serum and liver in 6% casein Pb-administered group were lower than in control group. Pb contents of serum, liver, and kidney were significantly increased in 6% casein-Pb administered group. Fe contents of serum and kidney were increased in 40% casein Pb-administered group, whereas in liver, 6% casein Pb-administered group was higher than others.

• Korean Journal of Agricultural Science
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• v.8 no.1
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• pp.44-50
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• 1981

This experiments was carried out to evaluate the effect of nitrogen retention on different levels of crude protein intake according to live weight, and the crude protein and urea content in serum of the Korean native goat. The results obtained are as follows: 1. When the female goat at 8 months age (14kg) had taken nitrogen free diet, the content of endogenous urinary nitrogen was 1.29g and endogenous fecal nitrogen was 1.27g per day. Therefore, the goat needs minimum level of crude protein per day. 2. When the thermometer checked below-$10^{\circ}C$, the nitrogen retention rate showed minus reaction in spite of 20% crude protein level. This suggested that the low temperature was consumed higher energy to maintain the body. 3. The nitrogen retention rate of the pregnant female goat of 20kg live weight, however, decreased as compared with the growing goat and was 17~20%. 4. According to the levels of crude protein were lower, crude protein and urinary nitrogen contents in serum were greatly decreased.