• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.6
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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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.1
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• pp.15-18
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• 1993

To evaluate an effect of dietary protein on the intoxication of methanethiol in rats, the methanethiol was intraperitoneally injected to the rats fed a low or high protein diet and then the liver weight per body weight and seurm levels of alanine aminotransferase (ALT) activities were determined to investigate the differences in liver damage between the animal groups fed low protein diet and that fed high protein diet. On the other hand, the hepatic glutathione content and its conjugating enzyme, glutathione S-transferase (GST) activity were determined to clarify the cause of difference in liver function between the two groups. The increasing rate of liver weigh/body wt., serum levels of ALT to its control group were higher in methanethiol-treated rats fed low protein diet than those fed high protein diet. The hepatic content of glutathione and GST activity were higher in rats fed high protein diet than those fed low protein diet and the decreasing rate of hepatic glu-tathione content to its control group was higher in rats fed low protein diet than those fed high protein diet. Furthermore, the hepatic GST activity in methanethiol-treated rats was higher in rats fed high protein diet than those fed low protein diet. In case of control group, the GST activity was also higher in rats fed high protein diet than those fed low protein diet.

• Korean Journal of Poultry Science
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• v.34 no.3
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• pp.217-222
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• 2007

This study was conducted to investigate the effects of mud flat bacteria origin protease supplementation by crude protein level on growth performance, nutrient digestibility, total protein and BUN (blood urea nitrogen) concentration in broilers. A total of four hundred eighty broilers were randomly allocated into four treatments with six replications for five weeks. Dietary treatments included 1) high crude protein diet, 2) high crude protein diet + 0.1% protease, 3) low crude protein diet and 4) low crude protein diet + 0.1% protease. During the entire experimental period, weight gain and feed/gain were improved in treatments of high crude protein diets and low crude protein diet added protease compared with treatment of low crude protein diet without protease (P<0.05). Similarly, DM digestibility was also improved in treatments of high crude protein diets and low crude protein diet added protease compared with treatment of low crude protein diet without protease (P<0.05). N digestibility was improved in treatment of high crude protein diet added protease compared with low crude protein diet without protease (P<0.05). Total protein concentration in blood was increased in treatment of high crude protein diet without protease compared with other treatments (P<0.05). In conclusion, mud flat origin protease was effective in improving weight gain, feed/gain and nutrient digestibility, and influenced blood total protein in broilers.

• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.2
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• pp.127-131
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• 1993

To evaluate an effect of dietary protein on lipoprotein profile serum of carbon tetrachloride-treated rats, carbon tetrachloride (50% in olive oil) was twice given at 0.1ml/100g body weight at intervals of 24hours to the male rats and then the degree of liver damage in carbon tetrachloride-treated animals fed a low protein diet was compared with that fed a high protein diet. The increasing rate of liver weight/body weight and the serum levels of alanine aminotransferase in carbon tetrachloride-treated rats to the control group were higher in rats fed high protein diet than those fed low protein diet. In the serum levels of lipid (total lipid, total cholesterol and triglyceride) remarkable differences were not found between low protein diet group and high protein diet group. But these serum lipids in carbon tetrachloride-treated rats were decreased and the decreasing rate of serum lipids to control group were higher in carbon tetrachloride-treated rats fed high protein diet than those fed low protein diet. Under the animal model as identified by the present data herein, serum pre $\beta$-lipoprotein and $\alpha$-lipoprotein fractions were decreased in carbon tetrachloride-treated rats, but the serum levels of $\beta$-lipoprotein were rather increased in the both group by the injection of carbon tetrachloride. Especially, the decreasing rate of $\alpha$-lipoprotein fraction was higher in $CCl_4$-treated rats fed a high protein diet than those fed a low protein diet to its control group and the increasing rate of serum $\beta$-lipoprotein fraction was also higher in $CCl_4$-treated rats fed high protein diet than those fed low protein diet.

• Journal of the Korean Home Economics Association
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• v.18 no.4
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• pp.103-107
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• 1980

This study was conducted to compare the effect of dietary sucrose and starch on the lipid metabolism of Rat fed by low protein diet for 3 and 6 weeks periods. Forty male weanling Spargue-Dawley rats weighing 52.7 grams each, after being adopted for 2 days with standard diet, were blocked into 8 groups and fed experimental diet as designed. Experimental diet were composed of two different levels of proteins, 6% designed as low protein diet and 15% designed as standard protein diet. In each group, the content of serum lipid, serum cholesterol and liver lipid were measured. The results of this experiment were summerized as follows. 1. liver lipid content was tended to be high in the sucrose group of low protein fed animal. 2. the content of total serum lipid was tended to be high in the sucrose group, and this tendency was showed statistical significance in the animals fed by low and standard protein after 6 weeks of experimental period. 3. The difference in the total serum cholesterol content between the sucrose and starch group was not significant

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.11
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• pp.1523-1528
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• 2000

Four Suffolk ewes were used in Latin Square switch over design to study the effects of varying levels and sources of protein on heat production and thermoregulatory responses at daytime high ($33^{\circ}C$ temperature. They were fed Italian ryegrass hay supplemented with fishmeal and/or urea, providing three different levels of crude protein (CP) (low/unsupplemented: 7.9, medium: 11.6, and high: 15.8%) at $1.5{\times}maintenance$. Feeds were distributed at 0900 (30%) and 1700 (70%). Urea diet caused higher heat production and increased vaginal temperature compared to fishmeal and fishmeal-urea mix diets. Time spent standing, skin temperature and respiration rate of sheep fed urea were similar with those of sheep fed fishmeal. Sheep fed diet with low CP level had higher heat production, increased vaginal and skin temperature than sheep fed diet with medium CP content. Sheep on high CP diet produced significantly more heat than sheep fed medium CP diets. Their vaginal temperatures were similar with those of sheep fed medium CP diet but lower than those of sheep fed low CP diet. Respiration rates of sheep and time spent by them for standing on all diets did not differ significantly. These results suggest that urea is inferior protein supplement for thermoregulation of animal at hot environment, as it induced higher heat production than fishmeal and fishmeal-urea mix. Thermoregulatory response on fishmeal-urea mix diet was similar to fishmeal diet. Increasing CP of the diet from low to medium gives advantage for thermoregulation of animal. Increasing CP further to high level was not beneficial as it resulted in the responses of sheep similar to those on low protein diet.

• Korean Journal of Community Nutrition
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• v.24 no.6
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• pp.485-496
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• 2019

Objectives: This study was conducted to investigate the effect of a 6-week low-calorie diet (LCD) program including high protein-low carbohydrate protein bar on weight loss, blood pressure, and blood lipid profile in 40 overweight women according to dietary compliance. Methods: Subjects were 62 healthy overweight women (BMI ≥ 23.0 or body fat percentage ≥ 28%), aged 20~59 yrs who were provided a high protein-low carbohydrate protein bar (each 35 g, 154 kcal, protein energy %: 28.6%, carbohydrate energy %: 38.7%) as part of dinner for 6 weeks. Forty subjects who completed the whole diet program were categorized into high compliance (HC) group (days of eating protein bar ≥ 5 weeks) or low compliance (LC) group (days < 5 weeks). Results: Energy intake significantly decreased from 1,867.5 kcal at baseline to 1,137.4 kcal at 6 weeks for the HC group and from 1,971.7 kcal to 1,362.2 kcal for the LC group, respectively. On the other hand, a significant increase in protein energy percentage was observed in each group (HC group: 3.5%, LC group: 2.2%). Both groups showed significant decreases in weight (HC group: 1.8 kg, LC group: 1.1 kg), BMI, fat mass, systolic blood pressure, total cholesterol, and LDL-cholesterol. Reduction of body fat percentage and diastolic blood pressure were only observed in the HC group. Conclusions: The inclusion of a high protein-low carbohydrate protein bar as part of a low-calorie diet for a short period can be effective to achieve weight loss and concomitantly improve blood cholesterol level without serious physiological side effects. More evident results can be achieved by eating a diet with low calorie diet including high protein-low carbohydrate protein bar for more than 5 weeks.

• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.156-163
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• 2014

We investigated the effects of a high-protein diet and resveratrol supplementation on immune cells changes induced by abdominal irradiation in rats. Female Wistar rats were divided into 5 groups: 1) control diet, 2) control diet with irradiation 3) 30% high-protein diet with irradiation, 4) normal diet with resveratrol supplementation and irradiation, and 5) 30% high-protein diet with resveratrol supplementation and irradiation. We measured blood protein and albumin concentrations, lipid profiles, white blood cell (WBC) counts, proinflammatory cytokine production, and splenocyte proliferation in rats that had been treated with a 17.5 Gy dose of radiation 30 days prior. A high-protein diet affected plasma total cholesterol and very low density lipoprotein-cholesterol levels, which were increased by the radiation treatment. In addition, the lymphocyte percentage and immunoglobulin M (IgM) concentration were increased, and the neutrophil percentage was decreased in rats fed a high-protein diet. Resveratrol supplementation decreased the triglyceride (TG) level, but increased the IgM concentration and splenocyte proliferation. Proinflammatory cytokine production was lower in rats fed a high-protein diet supplemented with resveratrol than in rats fed a control diet. The results of the present study indicate that high-protein diets, with or without resveratrol supplementation, might assist with recovery from radiation-induced inflammation by modulating immune cell percentages and cytokine production.

• Journal of Nutrition and Health
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• v.21 no.1
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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.

• Korean Journal of Poultry Science
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• v.44 no.2
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• pp.67-73
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• 2017

The purpose of our study was to determine the effects of varying levels of energy, protein, and amino acids on the performances of laying hens. A total of 240 Hy-Line Brown laying hens at 36 weeks of age were used in this 4-week feeding trial. The hens were randomly allocated to five treatment diets, with eight replications of six hens in each replicate cage. The treatment diets were as follows: A- basal diet + 18% crude protein, metabolizable energy 2,800 kcal, total (methionine + cysteine) 0.65%; B- basal diet + 17% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.59%; C- basal diet + 16.5% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.59%; D- basal diet + 16.5% crude protein, metabolizable energy 2,700 kcal, total (methionine + cysteine) 0.54%; and E- basal diet + 16% crude protein, metabolizable energy 2,680 kcal, total (methionine + cysteine) 0.54%. The study results revealed that the hen-day egg production of hens that were fed with low-energy diets (B, C, and D) was comparable with that of hens fed with high-energy diet A, whereas average daily feed intake in hens fed treatment diet D and E was significantly higher (P<0.05) than that in hens fed treatment diet A. Overall, the eggshell thickness was unaffected by any of the treatment diets. Egg weight was comparable among the treatment diets, except for treatment diet E. Haugh unit improved with decreasing levels of dietary energy, protein, and methionine + cysteine in the diet. We can summarize that laying hens fed with low dietary energy and low crude protein treatment diets B, C, and D had satisfactory performance compared with those fed with high-energy treatment diet A. This indicates that there is the potential to reduce feed costs by formulating diets with lower energy and low protein levels.