• Asian-Australasian Journal of Animal Sciences
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• v.21 no.8
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• pp.1159-1163
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• 2008

Data of 42 balance measurements from dry and lactating Holstein cows and blood and urine samples from 24 Japanese Black cows were collected to evaluate the potential for predicting urinary nitrogen (N) excretion from plasma urea nitrogen (PUN). Similar positive correlations were obtained between N intake and apparent N absorption in dry and lactating cows. The regression equations of N intake on urinary N excretion varied in dry and lactating cows, and the difference of urinary N excretion between dry and lactating cows was due to the N secretion into milk. Highly positive correlations were observed between urinary N contents and urinary urea N in Japanese Black cows, and urinary urea N increased with increasing PUN. There were positive correlations between N intake and PUN in dry and lactating cows, but PUN and urinary N excretion in lactating cows were higher than in dry cows. There were positive correlations between PUN and urinary N excretion per BW in dry and lactating cows. Although urinary N excretion could be calculated as (N clearance rate of kidneys)PUNBW, high N clearance rate of kidneys, such as 2.08 L/d/kg BW, may be suitable to calculate urinary N excretion in lactating cows, compared with 1.33 L/d/kg BW in dry cows.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.504-508
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• 1991

In order to investigate whether the function of distal nephron is disturbed in adenine-induced renal failure rats, we measured the urinary kallikrein level in adenine-ingesting rats fed on 0.75% adenine diet for 1 to 10 days. Administration of 0.75% adenine to rats significantly increased blood urea nitrogen level and urine volume, while the level of kallikrein along with the urinary excretions of urea and inorganic phosphate were significantly decreased. From these results, it is suggested that adenine-induced renal failure is caused by early deterioration of distal nephron as well as proximal nephron.

• Korean Journal of Veterinary Research
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• v.25 no.1
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• pp.41-48
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• 1985

In the present studies, the effects of dietary high-potassium and high-urea on the metabolism of magnesium, calcium and potassium were checked as an aid to clarify the pathogenesis of hypomagnesaemia(so-called grass tetany) in ruminant. A total of 5 Korean native female goats kept in metabolic cage were received high-potassium(Mg: 0.25%, Ca: 0.94%, K: 5.41%), high-urea(Mg: 0.25%, Ca: 0.94%, K: 0.72%) or control(Mg: 0.25%, Ca: 0.94, K: 0.72%) ration for 15 or 21 days. Daily intakes, fecal and urinary excretions and serum concentrations of magnesium, calcium and potassium were measured with an atomic absorption spectrophotometer. The results obtained were summarized as follows: In high-potassium group, absorption, urinary excretion and serum concentration of magnesium were significantly (p<0.01, p<0.01 and p<0.05 respectively) decreased compared with the control group. On the other hand, the body retention was significantly (p<0.01) increased. However, no clinical symptom of hypomagnesaemic tetany was observable throughout the experimental period. No significant effects on the metabolism and seurm content of calcium were detected in the high-potassium group. In the high-potassium group, significant increase in absorption (p<0.01), urinary excretion (p<0.05) and body retention (p<0.01) of potassium were recognized. However, no significant difference in the concentration of serum was observable between the two groups. In high-urea group, no significant difference in the metabolism of magnesium and potassium or in the serum content were recognized compared with the control group. In high-urea group, tthe absorption, urinary excretion, body retention and serum content of calcium were decreased compared with the control group.

• 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.

• Journal of Nutrition and Health
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• v.25 no.5
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• pp.397-403
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• 1992

This study was performed to investigate the effect of dietary magenesium on stress reactions in rats having abdominal surgery. Sixty three male rats of sprague-dawley strain were blocked into 3 groups : rats fed regular magnesium (0.05% Mg: control) rats receiving regular magnesium with surgery(Mg-adeq : S) Five weeks after feeding abdominal surgery was performed and randomly chosen 7 rats from each group were sacrificed on 1, 3 and 5 days after surgery. Te following were found ; 1) Rats fed marginal magnesium showed significantly elevated urinary urea nitrogen urinary potassium and plasma glucose compared controls only one day after abdominal surgery but not 3 days or 5 days after surgery 2) Rats fed adequate magnesium did not show any significant change in metabolic stress indicator after surgery. 3) Plasma free fatty acid and cortisol level were not different among groups. 4) Decreased plasma magnesium and potassium level were found in rats fed marginal magne-sium and sacrificed one day and three days after surgery.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.3
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• pp.241-245
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• 1996

A chronological account of the prospect and problems of utilization of urea in poultry diets is presented. Urea has long been considered as toxic to poultry but recent research, although limited, has yielded controversial results. The main problem appears to be due to the fact that whether or not response to urea is dependent on environment (germ free versus conventional). Although caecum is found to be the major site of ammonia production from urea, the so called nutritional benefit derived by chicken fed urea is probably limited to its utilization for the synthesis of nonessential amino acids in the protein depleted chicken, but not in the protein adequate chicken. More research is needed to monitor production characteristics of birds fed urea and investigate its toxic effect, if any, in some greater detail before recommending this nonprotein nitrogenous substance for inclusion in the poultry diets.

• Journal of Nutrition and Health
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• v.20 no.2
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• pp.90-103
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• 1987

A study was conducted to measure nitrogen intake and excretion in young korean women on their normal diet and leading normal activity level. Dietary survey by food record, fecal and urinary samples were collected for 3 days in 19 healthy female college students in Korea. On one of the 3 days, duplicate of one-day diet was collected from each subjects. Mean daily intakes of energy and protein were calculated from food recorded. Duplicate diet samples and pooled fecal samples were analyzed for N content. Pooled urine samples were analyzed for total N, urea N, and creatinine content. Apparent N absorption, apparent N balance and urea N/creatinine N were calculated to evaluate protein nutritional status. The results obtained are summarized as following ; 1) Accordingly to food record, mean daily intakes of energy, protein, carbohydrate and far were 1535.2 $\pm$53.78Kcal, 55.95$\pm$2.97g(total nitrogen 8.95$\pm$0.45g), 254.13$\pm$10.31g and 39.24$\pm$2.76 g, providing 14.6%, 66.2%, 19.2% of total energy respectively. 2) Nitrogen intake by chemical analysis was 7.16$\pm$0.31g/day (protein 44.75$\pm$1.94kg/day) providing 82.39$\pm$4.58% of nitrogen intake by food record. The difference of total nitrogen intake between food record and chemical analysis in diets was significant(p<0.05). 3) Mean daily fecal nitrogen excretion was 1.38$\pm$0.10g and then mean apparent digesbility of protein was 80.53$\pm$5.21%. 4) Mean daily urinary nitrogen excretion, urea N excretion and creatinine excretion were 6.03$\pm$0.30g, 4.52$\pm$0.22g, and 0.88$\pm$0.04g respectively. Urinary urea nitrogen was 75.2$\pm$1.38% of total urinary nitrogen excretion and urinary nitrogen was 85.4$\pm$3.56% of total nitrogen intake by chemical analysis. 5) Mean urea N/creatinine N ration was 14.01$\pm$0.77. 6) Mean nitrogen balance was -0.244$\pm$0.33g/day. From the above results, it is concluded that the subjects in this study seem to be in marginal protein nutritional status and therefore should increase dietary protein intake.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.1
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• pp.81-90
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• 1992

Five buffaloes kept in normal ambient temperature ($30^{\circ}C$) showed no significant changes in the heart rate, respiratory rate, packed cell volume, plasma constituents and renal hemodymics during intravenous infusion of urea for 4 h. The rate of urine flow, fractional urea excretion, urinary potassium excretion and osmolar clearance significantly decreased while the renal urea reabsorption markedly increased during urea infusion. The decrease of fractional potassium excretion was concomitant with the reduction of the rate of urine flow and urine pH. In animals exposed to heat ($40^{\circ}C$) the rectal temperature heart rate and respiratory rate significantly increased while no significant changes in GFR and ERPF were observed. An intravenous infusion of urea in heat exposed animals caused the reduction of the rate of urine flow with no changes in renal urea reabsorption, urine pH and fractional electrolyte excretions. During heat exposure, there were marked increases in concentrations of total plasma protein and plasma creatinine whereas plasma inorganic phosphorus concentration significantly decreased. It is concluded that an increase in renal urea reabsorption during urea infusion in buffaloes kept in normal ambient temperature depends on the rate of urine flow which affect by an osmotic diuretic effect of electrolytes. The limitation of renal urea reabsorption in heat stressed animals would be attributed to an increases in either plasma pool size of nitrogenous substance or body metabolism.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.6
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• pp.795-801
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• 2005

Eighteen Suffolk wether lambs (BW = 24 kg) were chronically exposed to temperatures of cold (2$^{\circ}C$) or warm (22$^{\circ}C$). The experimental design consisted of a 2${\times}$3 factorial with a single crossover of environment treatment. The sheep were closely shorn and were housed in individual metabolic crates in controlled environment rooms. Sheep consumed pelleted diets ad libitum, which consisted of mainly barley grain and brome grass, and diets contained 7, 11 or 14% crude protein (CP). Animals were catheterized via one jugular vein with a PVC catheter and received a single injection of 60-65 Ci of $^{14}$C]urea. Plasma urea-N (PUN), urinary urea (UU), and carbon specific radioactivity were measured. Urea metabolism was not affected by environment. Percent urea recycling and urea space clearance were highest (p<0.05) on the low nitrogen diet. Urea pool was increased (p<0.10) for the 14% CP diet. Both UU and PUN concentration were positively related (p<0.01) with diet CP content. Therefore, dietary CP content significantly influenced urea metabolism, however, cold exposure did not alter those parameters.

• Journal of the East Asian Society of Dietary Life
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• v.9 no.4
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• pp.427-434
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• 1999

This study was conducted to investigate the effects of vitamin I supplementation on renal function in high fat diet and adriamycin (ADR) induced experimental nephrotic syndrome in model rats. The effects of vitamin E supplementation on renal function in high fat diet and ADR treated rats were as follows. Kidney weight was decreased by vitamin E supplementation. Serum total protein was increased by the excess supplementation. Blood urea nitrogen(BUN) was decreased by the high supplementation. However, serum albumin and creatinine showed no significant differences between groups. Urinary volume tended to increase by vitamin I supplementation. Urinary urea-N tended by vitamin I supplementation. Particularly glomerular filtration rate(GFR) was significantly decreased by vitamin E supplementation. These results suggested that vitamin E supplementation could alleviate the adverse effects caused in renal function by highfatdiet and ADR treatments.