• Asian-Australasian Journal of Animal Sciences
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• 제24권9호
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• pp.1274-1281
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• 2011

Dietary protein restriction affects lipid metabolism in rats. This study was performed to determine the effect of a low protein diet on hepatic lipid metabolism and insulin sensitivity in growing male rats. Growing rats were fed either a control 20% protein diet or an 8% low protein diet. Feeding a low protein diet for four weeks from 8 weeks of age induced a fatty liver. Expression of acetyl-CoA carboxylase, a key lipogenic enzyme, was increased in rats fed a low protein diet. Feeding a low protein diet decreased very low density lipoprotein (VLDL) secretion without statistical significance. Feeding a low protein diet down-regulated protein expression of microsomal triglyceride transfer protein, an important enzyme of VLDL secretion. Feeding a low protein diet increased serum adiponectin levels. We performed glucose tolerance test (GTT) and insulin tolerance test (ITT). Both GTT and ITT were increased in protein-restricted growing rats. Our results demonstrate that dietary protein restriction increases insulin sensitivity and that this could be due to low-protein diet-mediated metabolic adaptation. In addition, increased adiponectin levels may influences insulin sensitivity. In conclusion, dietary protein restriction induces a fatty liver. Both increased lipogenesis and decreased VLDL secretion has contributed to this metabolic changes. In addition, insulin resistance was not associated with fatty liver induced by protein restriction.

• 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.

• 한국식품영양과학회지
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• 제23권6호
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• pp.894-898
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• 1994

To evaluate an effect of dietary protein on the liver damage, the bromobenzene was intraperitoneally injected to the rats fed a low or high protein diet and then the liver weight per body weight and serum levels of alanine aminotransferase (ALT) activities were determined to demonstrate the differences in liver damage between the groups fed low or high protein diet. Hepatic aniline hydroxylase (AH), glutthione (GSH) content and glutathione s-transferase(GST) activity were also determined to clarify causes of liver damage between the two groups. Increases of liver weight per body weight and serum ALT activities were higher in brombenzene treated rats fed low protein diet than those fed high protein diet. The increasing rate of hepatic AH activity was higher in bromobenzne-treated rats fed low protein diet than that in those fed high protein diet. Furthermore , hepatic glutathione contents and GST activities in bromobenzene-treated rats were higher in rats fed high protein diet than those fed low protein diet. In case of control group, the heaptic glutathione content and GST activity were also higher in rats fed high protein diet than those fed low protein diet.

• Asian-Australasian Journal of Animal Sciences
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• 제7권2호
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• pp.207-212
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• 1994

Effects of dietary cellulose and protein levels on nutrient utilization in chickens were investigated. Four experimental diets containing 5% (low cellulose) or 20% (high cellulose) cellulose in combination with 10% (low protein) or 20% (high protein) protein of 70 g/day were alternatively forced-fed to eight colostomized White Leghorn cockerels once a day to make $4{\times}4$ Latin-square design. The digestibilities of DM and energy decreased with the increase in cellulose level, but not affected by dietary protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose protein level. Ether extract digestibility was higher in the high cellulose diets than in the low cellulose diets. The digestibility of nitrogen free extract had the same trend with the digestibility of DM and energy. The digestibility of acid detergent fiber was not so much different among the diets, but the NDF digestibility was lower in the high cellulose diets than in the low cellulose diets, due to the low hemicellulose digestibility. The true digestibility of protein was influenced by both of the dietary protein and cellulose levels, and their interaction was found. The dietary protein level affected the biological value of protein but the dietary cellulose level did not, and consequently the biological value of protein in the low protein diets was lower than in the high protein diets.

• 한국가금학회지
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• 제34권3호
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• pp.217-222
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• 2007

본 연구는 육계 사료 내 조단백질 수준에 따른 갯벌 미생물 유래 단백질 분해효소제를 첨가하였을 때 생산성, 영양소 소화율 및 혈액 내 total protein과 BUN 함량에 미치는 영향을 알아보기 위해 실시하였다. 사양 시험은 2일령 Arbor Acres 육계(male) 480수를 공시하여 5주간 실시하였다. 시험 설계는 기초 사료 내 조단백질 함량과 효소제의 첨가 유무에 따라 high crude protein diet 처리구, high crude protein diet에 단백질 분해 효소제를 첨가한 처리구(high crude protein diet+0.1% protease), low crude protein diet 처리구 및 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구(low crude protein diet+0.1% protease)로 4처리($2{\times}2$ factorial)를 하여 처리당 6반복, 반복당 20수씩 완전 임의 배치하였다. 전체 사양 시험 기간 동안, 증체량은 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 높게 나타났다(P<0.05). 사료 섭취량에서는 처리구간에 유의적인 차이를 보이지 않았다. 사료 요구율에서는 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 낮게 나타났다(P<0.05). 또한, 건물 소화율은 high crude protein diet 처리구들과 low crude protein diet에 단백질 분해효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 높게 나타났고(P<0.05), 질소 소화율에서는 high crude protein diet에 단백질 분해 효소제를 첨가한 처리구가 low crude protein diet 처리구와 비교하여 유의적으로 증가하였다(P<0.05). 혈액 내 total protein 함량은 high crude protein diet 처리구가 다른 처리구들과 비교하여 유의적으로 증가하였고(P<0.05), BUN 함량은 처리구들 간에 유의적인 차이를 보이지 않았다. 결론적으로, 육계 사료 내 조단백질 수준에 따른 갯벌 미생물 유래 단백질 분해효소제의 첨가는 증체량, 사료 요구율, 영양소 소화율을 개선시켰고, 혈액 내 total protein 함량에 영향을 미쳤다.

• 한국가금학회지
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• 제21권4호
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• pp.257-266
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• 1994

Three protein feeding systems for egg-type pullets involving conventional step-down protein 18-15-12%), step-up protein(12-15-18%) and single-stage low protein (13-13-13%) with an iso-energy level of 2,900 ME kcal /kg were compared to examine the effect on pullet growth and subsequent laying performance. During the growing period, pullets subjected to the step-up and single-stage low protein feeding systems were lighter in body weight and consumed less feed and netabolizable energy than those on the conventional step-down protein feeding system(P<0.05). 3ut the pullets on the step-up protein diet consumed more protein, and those on the single-stage low protein diet consumed less protein than those on the step-down protein diet(P<0.05). Also, he feed cost was less in pullets on the single-stage low protein diet than in those on the other systems(P<0.05). During the laying period, sexual maturity was later in hens reared on the step-up and single-stage low protein diets than in those on the step-down protein diet(P<0.05), however, average hen-day egg production and egg weight were not significantly affected by the protein feeding systems in the growing period. Daily feed intake and feed required per egg were significantly reduced in hens on the single-stage low protein diet compared to those on conventional protein feeding system(P<0.05). It was concluded that the 13% single-stage low protein feeding system produced smaller pullets with less feed, energy, protein, and feed cost during the growing period, and hens reared on that system consumed less feed during the laying period without any impairment of production compared to the conventional rearing system.

• 한국식품영양과학회지
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• 제22권1호
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• pp.15-18
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• 1993

식이성단백이 methanethiol에 의한 간기능에 어떠한 영향을 미치는지를 검토코자 흰쥐를 저단백식이(LP : casein 7%) 및 고단백식이 (HP : casein 20%)로 1개월간 성장시킨 뒤 methanethiol을 투여한 다음, 간무게, 혈청 ALT 활성을 측정하여 간기능 정도를 두 군간에 비교하였다. 동시에 이에 대한 원인을 규명하는 일환으로 간조직 중 glutahione함량과 glutathione 포함효소의 일종인 glutathione S-transferase (GST)활성을 측정하여 다음과 같은 실험 결과를 얻었다. Methanethiol 투여로 인한 대조군에 대한 간무게와 혈청 ALT활성 증가율은 LP군이 HP군보다 높았으며, 간 glutathione함량과 간 GST활성이 HP군 보다 LP군이 낮게 나타났다. 이상 성적을 종합해 볼 때 methanethiol에 의한 간 독성은 식이 중 단백함량감소에 비례해서 증가되며 이는 LP군이 HP군 보다 methanethiol해독에 관여하는 간 glutathione함량과 GST활성의 감소에 기인되기 때문인 것으로 생각된다.

• 동아시아식생활학회지
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• 제5권3호
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• pp.385-394
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• 1995

Our previous reports on the effect of dietary protein on methanethiol, ethacrynic acid, bromobenzene and carbon tetrachloride metabolism were overall reviewed. The methanethiol, ethacrynicacid and bromobenzene treated rats showed the more severe liver damage in those fed a low protein diet than those fed a standard protein diet. These xenobiotics treated rats showed the lower content of hepatic glutathione and its conjugated enzyme, glutathione S-transferase activities in those fed a low protein diet than those fed a standard protein diet. In case of carbon tetrachloride treated rats, the liver damage was more reduced in rats fed a low protein diet than those fed a standard protein diet. Concomitantly the hepatic cytochrome P-450 content, and its decreasing rate to the control were lower in rats fed a low protein diet than those fed a standard protein diet.

• Molecules and Cells
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• 제25권3호
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• pp.446-451
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• 2008

We assessed heterologous protein expression in 64 strains obtained from the Escherichia coli Reference (ECOR) collection, a collection representing diverse natural E. coli populations. A plasmid generating a glutathione S-transferase and plant carbonic anhydrase fusion protein (GST-CA) under the control of the tac promoter was introduced into the ECOR strains, and the quantity of the fusion protein was determined by SDS-PAGE. The foreign protein was generated at various levels, from very high (40 strains, high producers) to very low (six strains, low producers). Immunoblotting showed that the high producers expressed approximately 250-500 times more GST-CA protein than the low producers. The results of semi-quantitative RT-PCR showed that the low producers generated mRNA levels comparable to those of the high producers, thereby suggesting that, at least in this case, inefficient translation is a major cause of the low production. We introduced a different plasmid, which expressed a maltose binding protein and plant guanylate kinase fusion protein (MBP-GK) into the six low producers. Interestingly, five of these expressed MBP-GK at very high levels. Thus, we conclude that the production of a particular protein from an expression vector can vary considerably, depending on the host strain. Strains in the ECOR collection could function as useful alternative hosts when a desired level of protein expression is not obtained from commonly used strains, such as E. coli K12 or B derivatives.

• Nutritional Sciences
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• 제1권1호
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• pp.3-7
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• 1998

The aim of the present investigation was to see whether an anabolic steroid, nandrolone phenylpropionate (NPP), exerts protienanabolic effects under such adverse nutritional conditions as protein deficiency and protein-energy malnutrition in male rats. feeding on a low-protein (8% casein) diet resulted in a marked reduction in body weight gain that was associated with reductions in body protein and protein content of gastrocnemius muscle. Administration of NPP (4 mg/kg body weight) did not alter muscle and body protein depletion induced by a low-protein diet. 50% food restriction caused reductions in body protein and in protein content of gastrocnemius muscle. These reductions were partially prevented by NPP (4 mg/kg body weight). Food restriction did not affect plasma concentration of corticosterone, insulin, or tetosterone plus dihydrotestosterone. On the other hand, neither plasma concentration of corticosterone nor insulin were affected by NPP. The present results show that anabolic steroids do not express anabolic effects under conditions of protein deficiency, but in protein-energy malnutrition, anabolic steroids exert their anabolic effects even in male rats.