Plasma urea nitrogen as an indicator of protein quality. II.* Relationships between plasma urea nitrogen, various urinary nitrogen constituents, and protein quality

1976 ◽  
Vol 27 (1) ◽  
pp. 117 ◽  
Author(s):  
RD Kirk ◽  
DM Walker
Keyword(s):  
Nitrogen Balance ◽  
Protein Quality ◽  
Dietary Treatment ◽  
Soya Bean ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
Before And After ◽  
Protein Diets ◽  
Urinary Nitrogen

Preruminant male crossbred lambs aged 2–5 days at the start of the experiment were used. Plasma urea nitrogen (PUN) and nitrogen balance were significantly correlated (r = – 0.74) in lambs given a wide variety of plant and animal proteins in low protein diets (0.10 of total energy as protein). Nevertheless, lambs having identical intakes of nitrogen and energy from diets containing different proteins could have identical PUN values but significantly different nitrogen balances. It was shown with groups of lambs that PUN could be used to predict the minimum amount of DL-methionine that was required to give maximum nitrogen balance, when used as a supplement to isolated soya bean protein. It was also shown that there were significant daily variations in PUN and in the excretion of urinary nitrogen constituents (urea, ammonia, creatinine) between and within lambs given the same diet under strictly controlled conditions. It was concluded that no further increase in the precision of predicting protein quality from PUN (or urinary nitrogen constituents) was possible, unless an experimental design was used in which the values for individual lambs were compared before and after a change in dietary treatment. __________________ *Part I, Aust. J. Agric. Res., 27: 109 (1976).

scholarly journals Nitrogen balance of starting barrow pigs fed on increasing lysine levels

2004 ◽  
Vol 47 (1) ◽  
pp. 85-91 ◽  
Author(s):  
Ivan Moreira ◽  
Alessandro Luis Fraga ◽  
Diovani Paiano ◽  
Gisele Cristina de Oliveira ◽  
Cláudio Scapinello ◽  
...  
Keyword(s):  
Nitrogen Balance ◽  
Nitrogen Retention ◽  
Nitrogen Excretion ◽  
Protein Utilization ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
Feed Protein ◽  
Protein Diets ◽  
Net Protein

The effects of increasing lysine levels on nitrogen balance of pigs fed on low protein diets were evaluated. Four treatments (diets) containing lysine levels (0.8, 1.0 1.2 and 1.4%) were applied to 12 starting (20.0 ± 1.8 kg) barrow pigs. Methionine, threonine and tryptophan were kept constant to the lysine ratio in all diets. Feces and urine were collected during a 5-day period. Nitrogen output in urine (NOU), total nitrogen output (TNO), nitrogen retention (NR), net protein utilization (NPU), biological value or feed protein (BVFP), urine urea nitrogen (UUN), and plasma urea nitrogen (PUN) were determined. PUN showed high negative correlations with BVFP (-0.84), NPU (-0.76), and NR (-0.78) and a positive correlation (0.79) to NOU. Lowest nitrogen excretion and the best use of diet protein were obtained with 1.1% total lysine level. PUN is efficient to indicate amino acid for pigs.

Plasma Urea Nitrogen Concentration and Growth Performance of Finishing Pigs Fed Sorghum-Soybean Meal, Low-Protein Diets

2008 ◽  
Vol 33 (1) ◽  
pp. 7-12 ◽  
Author(s):  
J. L. Figueroa ◽  
M. Martínez ◽  
J. E. Trujillo ◽  
V. Zamora ◽  
J. L. Cordero ◽  
...  
Keyword(s):  
Growth Performance ◽  
Soybean Meal ◽  
Nitrogen Concentration ◽  
Finishing Pigs ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
Protein Diets

scholarly journals Effect of CLA supplementation to low-protein diets on the growth performance, carcass characteristics, plasma urea nitrogen concentration, and fatty acid profile in the meat of pigs

2014 ◽  
Vol 57 (5) ◽  
pp. 742-754 ◽  
Author(s):  
Manuel Martínez-Aispuro ◽  
José Luis Figueroa-Velasco ◽  
Vicente Zamora-Zamora ◽  
José Luis Cordero-Mora ◽  
Carlos Narciso-Gaytán ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Growth Performance ◽  
Fatty Acid Profile ◽  
Nitrogen Concentration ◽  
Carcass Characteristics ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
Protein Diets

Plasma urea nitrogen as an indicator of protein quality. I. Factors affecting the concentration of urea in the blood of the preruminant lamb

1976 ◽  
Vol 27 (1) ◽  
pp. 109 ◽  
Author(s):  
RD Kirk ◽  
DM Walker
Keyword(s):  
Protein Content ◽  
Protein Concentration ◽  
Protein Quality ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Dry Matter Content ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
Gross Energy

Preruminant male crossbred lambs, aged between 2 days and 5 weeks, were given milk replacers of low (0.10 of total energy as protein) or medium (0.28) protein content. Plasma urea nitrogen (PUN) values were unaffected by: the time of blood sampling within 9 hr after feeding; the age of the lamb, between 3 and 33 days; the lamb's intake of the medium protein diet (range, 500–1180 kJ gross energy/day per kg0.73 storage of plasma samples at –15°C for 5 months before analysis; fasting of lambs for 4 days; feeding of lambs on a nitrogen-free diet for 7 days. PUN values were significantly increased by: an increase in the dietary protein concentration; a reduction in the lamb's intake of the low protein diet below 840 kJ gross energy/day per kg0.73 (negative nitrogen balance); an increase in the dry matter content of the medium protein diet from 0.10 to 0.25; the addition of urea to the low protein diet (peak values 4–6 hr after feeding). PUN values estimated on successive days reflected a change in the protein content of the diet within 3–4 days, regardless of whether the change in protein concentration was from low to medium, or medium to low. It is concluded that PUN values can be used to evaluate protein quality only when experimental conditions are strictly controlled. Blood samples taken without regard to the above factors may give misleading results.

The effects of continuous intravenous and intraruminal infusions of urea on nitrogen metabolism in sheep

1971 ◽  
Vol 22 (3) ◽  
pp. 429 ◽  
Author(s):  
KH McIntyre
Keyword(s):  
Nitrogen Metabolism ◽  
Nitrogen Balance ◽  
Nitrogen Concentration ◽  
Route Of Administration ◽  
The Body ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Low Protein ◽  
Nitrogen Concentrations

Urea was infused into sheep both intravenously and intraruminally, and at several increasing rates. The infusions were continuous for at least 6 days for each quantity of urea infused. Three predominantly roughage rations were used. Two of these had the same roughage constituents; both had relatively low protein contents, but one contained starch. The amount of urea nitrogen retained in the body from the urea infused was greatest on the ration containing starch, when the nitrogen balance improved by as much as 4.3 g/day. The concentration of ammonia in the rumen increased linearly with the amount of urea infused by either route of administration, but was much higher in the sheep infused intraruminally. Plasma urea nitrogen concentrations increased linearly with each quantity of urea infused until they reached about 30 mg/100 ml. They increased above this concentration only in the sheep fed on the low protein roughage ration without starch. The results suggest that a renal mechanism for urea excretion may control the plasma urea nitrogen concentration at about 30 mg/100 ml under certain conditions.

Effects of feeding low protein diets to piglets on plasma urea nitrogen, faecal ammonia nitrogen, the incidence of diarrhoea and performance after weaning

2008 ◽  
Vol 62 (5) ◽  
pp. 343-358 ◽  
Author(s):  
Jung-Min Heo ◽  
Jae-Cheol Kim ◽  
Christian Fink Hansen ◽  
Bruce P. Mullan ◽  
David J. Hampson ◽  
...  
Keyword(s):  
Ammonia Nitrogen ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Low Protein ◽  
And Performance ◽  
Protein Diets

Salvage of Exogenous Urea Nitrogen Enhances Nitrogen Balance in Normal Men Consuming Marginally Inadequate Protein Diets

1996 ◽  
Vol 90 (3) ◽  
pp. 215-225 ◽  
Author(s):  
Tracey S. Meakins ◽  
Alan A. Jackson
Keyword(s):  
Nitrogen Balance ◽  
Urea Hydrolysis ◽  
The Body ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Urea Nitrogen ◽  
Low Protein ◽  
Significant Difference ◽  
Normal Men ◽  
Protein Diets

1. Urea kinetics were measured in six healthy men using prime/intermittent oral doses of [15N15N] urea, after five days consuming one of four diets which varied in their nitrogen content: a reference diet (REF, 70 g of protein and 11.2 g of N); a low-protein diet (LP, 30 g of protein and 4.8 g of N); a low-protein diet with 6.9 g of urea added (LP-U1, 30 g of protein and 8 g of N); a low-protein diet with 13.7 g of urea added (LP-U2, 30 g of protein and 11.2 g of N). 2. Apparent nitrogen balance on the REF diet was significantly better than on the LP or the LP-U1 diets. The addition of the higher level of urea in the LP-U2 diet enhanced apparent nitrogen balance compared with the LP or LP-U1 diets, and was not different to apparent nitrogen balance on the REF diet. 3. On the LP, LP-U1 and LP-U2 diets, the rate of endogenous urea production was not different, and was about 60% of that on the REF diet, a statistically significant difference. The addition of a dietary supplement of urea increased the rate of urea appearance in the urea pool in direct relation to the dose of urea taken. There was no difference in the rate of appearance between the REF and LP-U2 diets, for both of which the rate of appearance was significantly greater than on the LP diet. 4. The excretion of urea in urine on the LP diet was 62% of that on the REF diet, a significant difference. There was no significant difference in the rate of urea excretion between the REF, LP-U1 and LP-U2 diets. 5. The rate of urea hydrolysis by the colonic microflora on the REF diet was more than twice that on the LP or LP-U1 diets. Supplementation with urea at the higher level, LP-U2, significantly increased hydrolysis to the same level as on the REF diet. Most of the nitrogen derived from urea hydrolysis was retained in the metabolic pool (>80%), with no difference in the rate of retention between the REF and LP-U2 diets, both greater than the LP or LP-U1 diets. 6. The dietary supplements of urea increased the size of the body urea pool significantly. Renal clearance of urea was highest on the REF diet and decreased 13–29% on the low-protein diets. Bowel clearance was highest on the REF diet and decreased 46–55% on the low-protein diets. Neither urinary excretion of urea nor urea hydrolysis in the bowel were related simply to the concentration of urea in blood. Urea hydrolysis related most closely to the rate of appearance of urea in the urea pool. 7. The salvage of urea nitrogen was increased on the highest level of supplementation, but the overall sensitivity of the system was low, suggesting that other factors might be limiting for effective urea hydrolysis and the salvage of urea nitrogen.

The performance of calves given concentrate diets treated with formaldehyde

1973 ◽  
Vol 24 (4) ◽  
pp. 613 ◽  
Author(s):  
GJ Faichney ◽  
HL Davies
Keyword(s):  
Food Consumption ◽  
Protein Level ◽  
Rumen Fluid ◽  
Amino Nitrogen ◽  
Peanut Meal ◽  
Plasma Urea ◽  
Protein Levels ◽  
Low Protein ◽  
Formaldehyde Treatment ◽  
Protein Diets

Five groups of Friesian bull calves were given concentrate diets containing 70 % barley in which low (12 %), medium (15 %), and high (19%) protein levels were obtained by varying the amount of peanut meal included. The effects of protein level and of formaldehyde treatment of the complete diet at the low and medium protein levels were studied in terms of liveweight gain, voluntary food consumption, digestibility of the diet, ammonia nitrogen in rumen fluid, and urea and a-amino nitrogen in blood plasma. Observations were begun when the calves reached 70 kg liveweight and continued until they reached 130 kg liveweight. The calves given the low protein diets grew more slowly than those given the higher protein diets. The calves given the high protein diet grew no better than those given the medium protein diets. Formaldehyde treatment was associated with an increase in the rate of liveweight gain of 9% (P = 0.11) at the low protein level but had practically no effect at the medium protein level. The treatment did not adversely affect voluntary food consumption but was associated with decreases in the digestibility of nitrogen and in rumen ammonia levels and small increases in plasma urea levels.

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