• Asian-Australasian Journal of Animal Sciences
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• 제17권10호
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• pp.1447-1451
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• 2004

An experiment was conducted to determine the effects of different dietary crude protein (CP) levels on growth performance, nutrient utilization, small intestine protease activity and immunity index of weaner to 2 month-old New Zealand rabbits. Eighty weaner rabbits were allocated in individual cages to five treatments in which they were fed diets with CP at 14%, 16%, 18%, 20% and 22%, respectively. The growth performance and nutrient digestibility of rabbits increased firstly when dietary CP increased, then decreased. The average daily gain was the highest and feed conversion rate was the lowest when dietary CP reached 20%, namely 34.9 g/d and 2.74:1, respectively. Maximum CP digestibility was 72.1% in the 18% CP group, maximum crude fiber digestibility of 28.4% occurred in the 16% CP group and was significantly different from other treatments (p<0.01), apparent digestibility of Lys and Val followed the same trend as CP digestibility, and reached their maximum when dietary CP was 18%. Apparent digestibility of Cys, Tyr, Leu and Thr also had a similar trend to CP digestibility. Nitrogen retention (RN) increased with CP level (p>0.05), and was highest for 20% CP treatment (1.5 g/d). The effect of CP level on the rate of digestible nitrogen (DN) converted RN was small. The spleen index, thymus index, chymotrypsin and trypsin activities in small intestine were highest when dietary CP was 16%, which were 1.0, 2.8, 15.7 U/g and 125.7 U/g, respectively. There was no significant difference among treatments (p>0.05). According to the above results, the appropriate dietary CP level from weaner to 2 month-old meat rabbits was 18-20%.

• 한국수산과학회지
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• 제29권4호
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• pp.464-473
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• 1996

쥐노래미의 단백질 요구량을 조사하기 위해 카제인과 북양어분을 단백질원으로 하여, 사료의 단백질 함량이 30, 40, 50, $60\%$가 되도록 조정한 4종의 실험사료와 사료의 적정 에너지 함량을 조사하기 위해 가용에너지/단백질 (EP) 비가 9, 10, 11, 12인 4종의 실험 사료를 각각 설계하여 사육실험을 실시하였다. 29g 전후의 쥐노래미를 2개월간 사료의 단백질 함량별로 2반복으로 사육 실험한 결과, 증체율 및 사료효율은 모두 단백질 $50\%$ 사료에서 가장 좋았고, 단백질 $60\%$ 사료에서 성장효과는 오히려 감소하여 4개 실험구 중에서 가장 낮은 값을 나타내었다 (P<0.05). 수학적인 방법으로 이차회귀곡선상에서 증체율을 지표로 하여 단백질요구량을 추정한 결과 최대 단백질 요구량이 $45\%$로 나타났다. 일일사료섭취율은 실험구간에 서로 차이가 없었으나, 단백질섭취율은 사료의 단백질 함량이 증가됨에 따라 증가하는 경향을 보였으며, 단백질효율은 사료 단백질 함량이 증가될수록 유의하게 감소하였다(P<0.05). 가장 성장이 좋았던 실험구의 일일단백질섭취율이 어체중 100g 당 1.7g 이였으며, 이차회귀곡선상에서는 일일단백질 요구량이 어체중 100g당 1.5g으로 나타났다. 전어체의 수분함량은 사료 단백질 함량 $40\~60\%$구간에서는 차이가 없었으나, 사료 단백질 $30\%$구는 $40\%$구보다 유의하게 낮은 값을 보였다(P<0.05). 단백질과 회분 함량은 실험구간에 차이가 없었으며, 지질 함량은 단백질 $30\%$ 실험구가 가장 높았고, $40\%$ 실험구가 가장 낮았다(P<0.05) E/P 비가 다른 사료로 사육 실험한 결과, 증체율, 사료효율 및 단백질효율이 E/P 비가 12인 실험구가 다른 실험구보다 높은 값을 보였다. 전어체의 수분, 단백질 및 회분 함량은 사료의 에너지 함량에 영향을 받지 않았으나, 지질 함량은 에너지가 높은 사료인 E/P 비 11과 12 사료에서 유의적으로 높은 값을 보였다. 본 실험 결과로부터 평균체중 100g 이하의 성장기 쥐노래미의 단백질 요구량은 $45\~50\%$, 일일단백질 요구량은 어체중 100g 당 $1.5\~1.7g$으로 추정되며, 쥐노래미 사료의 적정 E/P 비는 12 전후가 적당할 것으로 생각된다.

• Journal of Nutrition and Health
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• 제21권1호
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• pp.47-60
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• 1988

This study was performed to investigate the effect of dietary levels on protein metabolism in eight healthy Korean adult females. The 20-day metabolic study consisted of 2 day adaptation period and three 6-day experimental. Three experimental diets were low protein (LP : protein 44g), high protein(HP : protein 85g) and high animal protein (HAP : protein-84g). The apparent absorption and balance on nitrogen were significantly higher in high protein than in low protein diet. Nitrogen, absorption rate was about 75% for low protein and about 85% for high protein intake. The mean values of nitrogen balance were -1.28% for low protein and 0.78% for high protein diet. All the subjects were in negative nitrogen balance at the low protein intake while they were in positive nitrogen balance at the high protein intake. The mean daily urinary nitrogen excretion increased with increased level of protein intake. Urea nitrogen was the largest part of the urinary nitrogen. The ratio of urea nitrogen to total urinary nitrogen increased significantly for 79 to 85% as protein intake was doubled.

• Asian-Australasian Journal of Animal Sciences
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• 제21권11호
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• pp.1616-1623
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• 2008

This study was conducted to determine the effect of hot environment and dietary crude protein level (CP) on performance, carcass characteristics, meat visual quality, muscle chemical composition and malondialdehyde (MDA) concentration of tissues in broilers. Two hundred and sixteen 21-d old Arbor Acre broilers were used in a $4\times3$ factorial arrangement and randomly reared in 4 environmental chambers and fed on 3 diets with different CP levels for 3 weeks. The results showed: (1) when air temperature (AT) rose to $33^{\circ}C$, average daily feed intake, average daily gain, carcass weight, right breast meat weight, left thigh and drumstick meat weight decreased (p<0.05) and feed conversion rate decreased (p<0.05), but the ratio of carcass to live weight and of left thigh and drumstick meat weight to carcass weight increased (p<0.05). (2) There were significant differences in pH and shear force in breast meat, and shear force, L* and a* in thigh meat (p<0.01 or 0.05) among hot environments. Dietary CP level tended to affect breast meat pH and pH and L* of thigh meat (p<0.06 or 0.09). Compared to the normal temperature ($22^{\circ}C$), low temperature ($15^{\circ}C$) and hot humid (AT $33^{\circ}C$, relative humidity (RH) 80%) treatments significantly (p<0.05) decreased the tenderness of thigh meat. L* and a* value in thigh meat under high temperature treatments, regardless of RH, were higher (p<0.05) than those under normal temperature. (3) Protein content in breast and thigh meat of broilers fed under high temperature ($33^{\circ}C$) was lower (p<0.05) than that under $22^{\circ}C$, but fat content had an adverse change. High temperature ($33^{\circ}C$) increased the moisture of breast meat significantly (p<0.05). Protein content in breast meat increased significantly (p<0.05), in which fat content had an adverse change (p<0.05), when the dietary protein rose. (4) MDA concentration in liver and breast meat under hot humid (AT $33^{\circ}C$, RH 80%) treatment increased markedly (p<0.05). (5) High humidity could sharpen the bad effect of high temperature on performance, carcass yield and choice cuts, crude protein and moisture content in breast meat. It was concluded that a hot environment could affect the performance and meat quality of broiler chicks more significantly than CP level and that high humidity would aggravate the bad influence of high temperature on the broiler.

• Asian-Australasian Journal of Animal Sciences
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• 제18권4호
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• pp.502-511
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• 2005

The effects of different levels of crude protein (CP) and cottonseed meal replacing for soybean meal in cassava chips and rice straw-based diets for mid-lactating cows (100-150 day in milk [DIM]), were studied using 32 multiparous Holstein Fresian crossbred dairy cows. Diets containing 10.5, 12.5, 13.7, 14.4% CP of the rations and 0, 12.1, 14.9, 17.8% cottonseed meal were fed to cows for 60 days. Thirty two cows were randomly divided into four dietary treatments using a Randomized complete block design. Four dietary treatments were offered in the form of total mixed ration (TMR) with concentrate to roughage (chopped rice straw) at 60:40 and offered ad libitum. Dry matter (DM) and neutral detergent fiber (NDF) intakes tended to linearly increase with increasing dietary CP levels. Intakes and digestibility of crude protein increased linearly with increasing dietary CP level (p<0.01). Crude protein digestibility of the 10.5% CP diet was lower (p<0.05) than that in diets with higher levels of CP, while there were no significant differences among the other three levels of CP (12.5, 13.7 and 14.4%). Daily milk yield tended to increase with increased CP from 10.5 to 14.4%. Income over feed in terms of US$/kg of milk increased with increased CP from 10.5 to 13.7% and decreased when the CP level was higher than 13.7% (quadratic effect p<0.09). Milk composition was not significantly affected by increasing level of CP, however there were relatively high contents of protein and fat among treatments. The proportion of milk-urea N (MUN), ammonia-N ($NH_3$-N) and bloodurea N (BUN) were closely correlated and increased linearly with increasing CP levels (p<0.01). Balanced diet was found in diet containing 12.5 and 13.7% CP of the rations when BUN and MUN were used as indicators of the protein to energy ratio in the diet. Conclusions can be made that increasing dietary CP levels from 10.5 to 13.7% using cottonseed meal as the main source to completely replace soybean meal was beneficial to cows consuming rice straw and cassava chips based-diets. Increasing the CP level above 13.7% of total ration did not additionally improve milk yield and composition or net income.

• Preventive Nutrition and Food Science
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• 제4권1호
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• pp.47-51
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• 1999

In order to evaluate the dietary regulation of cysteine sulfinic acid decarboxylase (EC 4.1.1.29) in cats, acitivity and protein content of CSAD were assessed in the liver and kidney of cats fed different levels of dietary protein, with and without taurine. Four groups of cats were fed one of the follow diets for 5 weeks ; 20% protein and taurine- free diet(LP0T) ; 20% protein and 0.15% taurine diet(LPNT) ; 60% protein and taurine-free diet(HP0T); and 60% protein and 0.15% taurine diet (HPNT). CSAD activity was determined in the liver and kidney of cats by measuring 14C2 released form [1-14C]-L cysteine sulfinic acid. CSAD protein was quantified using an immunochemical method. CSAD activity was extremely low in cat tissues, among which kidney showed the highest activity which was 0.118$\pm$0.050, and 0.377$\pm$0.056 nmol.min-1.mg soluble portein-1 iin animals fed LP0T and HP0T, respectively. Even though renal CSAD protein content was 18~55% of the hepatic CSAD protein content, renal CSAD acitivity was 1.3~6.5 times of the hepatic CSAD activity . Renal CSAD acitivities of cats fed 60% protein were about 1.6~3.2 times those of animals fed 2.% protein , and hepatic CSAD activity was not significantly affected by the dietary level of protein. Taurine depletion significantly elevated both hepatic and renal CSAD activities above the values for cats having normal taurine status most probably as an adaptive response.

• Journal of Nutrition and Health
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• 제45권3호
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• pp.211-217
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• 2012

UV-irradiation is a major factor of photo-aged skin, by which pigmentation, wrinkles and laxity are increased. In addition, the epidermal barrier is disrupted, ultimately causing dryness in photo-aged skin. As an effort to search dietary sources for improving the dryness of UV irradiated skin, the dietary effect of red ginseng based functional foods on the epidermal level of ceramides, a major lipid maintaining epidermal barrier, was determined in this study. Albino hairless mice were fed either a control diet [group UV (UV-irradiated control)] or diets with 0.5% (group M0.5) or 1% (group M1.0) of red ginseng extracts mixed with Torilis fructus and Corni fructus (66.7% red ginseng) in parallel with UV irradiation for 5 wks. A normal control group (group C) was fed a control diet without UV irradiation for 5 wks. The epidermal level of ceramides in group UV was significantly lower than that in group C, in which ceramidase, an enzyme involved in ceramide degradation, was highly expressed. In group M0.5, the epidermal level of ceramide was significantly increased to the level even higher than in group C. In addition, protein expression of serine palmitoyl transferase (SPT), a key enzyme involved in de novo ceramide synthesis, was increased in group M0.5. However the epidermal levels of ceramides as well as of ceramidase protein expression in group M1.0 did not differ from those in group UV. In conclusion, we demonstrate that dietary supplementation of red-ginseng extracts mixed with Torilis fructus and Corni fructus at a level of 0.5% level in diet increased the epidermal level of ceramides coupled with the elevated expression of SPT protein.

• Journal of Nutrition and Health
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• 제46권6호
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• pp.521-530
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• 2013

Protein-energy malnutrition, PEM, and increased hs-CRP level are considered to be associated with increased risk of cardiovascular disease (CVD) in hemodialysis (HD) patients. This is commonly referred to as the vicious circle of malnutrition-inflammation-atherosclerosis cardiovascular disease (MIA syndrome) in chronic kidney disease (CKD). Low protein intake can decrease the serum level of albumin and increase inflammational markers; further, both low serum albumin and high hs-CRP are independent risk factors for all-cause mortality in HD patients. The aim of this study is comparing the serum levels of albumin and hs-CRP in HD patients according to the protein intake levels. The total number of subjects was 60 hemodialysis patients; they were grouped by dietary protein intake: low protein intake group (LPI, protein intake < 1.0 g/kg IBW, 11 men and 19 women) and adequate protein intake group (API, protein intake ${\geq}$ 1.0g/kg IBW, 12 men and 18 women). Blood biochemical parameters, nutrient intake, and dietary behaviors were compared between the LPI and API groups. The LPI group showed a significantly lower serum level of albumin and higher serum level of hs-CRP than the API group (p < 0.05). The LPI group showed a significantly lower intake of most nutrients than the API group (p < 0.05). Index of Nutritional Quality of most nutrients of the LPI and API groups were lower than 1.0. Dietary protein intake was positively correlated with the serum level of albumin (r = 0.306, p < 0.05) and negatively correlated with the serum level of hs-CRP (r = -0.435, p < 0.01). The serum level of hs-CRP was negatively correlated with that of albumin (r = -0.393, p < 0.01). According to these result, serum albumin and hs-CRP in HD patients were influenced by the protein intake levels. To prevent MIA syndrome, it is necessary to improve nutritional status, especially in protein and energy.

• 동아시아식생활학회지
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• 제7권1호
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• pp.13-20
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• 1997

This study was designed to determine the effects of protein sources on the curation of gastric ulceration, protein metabolism, and nitrogen balance in rats with gastric ulcer induce by restraint and water immersion stress. After the rats were fed 10% casein diet for 3 weeks, four groups of the rats were forced in 5$\times$5$\times$15cm plexiglass cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hour. The other one group(control group) was not exposed to stress. After stress 4 kinds of different diets containing 20% protein were given for 5 days. The protein sources were casein, whey protein, soy protein, gluten. The control group was fed to 10% casein diet. The results were as follows ; the weights of rats were not different among the diet groups During the experiment period follows ; the weights of rats were not different among the diet groups during the experiment period (for 5 days). The ulcer index of rats fed 10% gluten and soy protein diet was significantly higher than those of casein and whey protein diet groups(p<0.05). The level of serum albumin was not significantly different among diet groups. But hematocrit and the level of $\alpha$-amino-N, BU and UUN of plant protein diet groups were higher than animal diet groups, the urinary hydroxyproline of soy protein group was the highest and the whey protein was the lowest. The digestibility and BV of nitrogen of gluten diet group were significantly higher than those of casein and whey protein diet groups(p<0.05). The animal proteins had more curative effects of ulcer than plant animals. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.

• Fisheries and Aquatic Sciences
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• 제21권10호
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• pp.30.1-30.6
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• 2018

A study of three feeding trials was conducted to investigate the dietary protein requirements of Pacific white shrimp (Litopenaeus vannamei) at three different growth stages. Six experimental diets were formulated to include increasing protein levels of 25, 30, 35, 40, 45, and 50% (designated as P25, P30, P35, P40, P45, and P50, respectively) for three feeding trials. The three feeding trials were conducted in different-sized shrimp at 0.65 g (trial 1), 4.80 g (trial 2), and 10.5 g (trial 3). Triplicate groups of shrimp were fed one of the experimental diets for 36, 42, and 48 days in trials 1, 2, and 3, respectively. In trial 1, the growth performance was not affected by the dietary protein levels. However, protein efficiency ratio was significantly higher in P30 diet compared to P40, P45, and P50 diets. In trial 2, growth rate was significantly higher in P35 diet than in P25 diet. In trial 3, the lowest growth performance was obtained in P25 diet which significantly differed from that of other experimental diets. Broken line analysis of growth data indicates that the optimal dietary level of crude protein is 34.5, 35.6, and 32.2% for small-, medium-, and large-sized (juvenile, sub-adult, and adult stages) Pacific white shrimp, respectively.