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.

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

Factors affecting the urinary excretion of urea nitrogen in cattle. II. The plasma urea nitrogen concentration

1970 ◽  
Vol 21 (1) ◽  
pp. 145 ◽  
Author(s):  
RF Thornton
Keyword(s):  
Nitrogen Concentration ◽  
Urine Flow ◽  
Urea Concentration ◽  
Urea Clearance ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Factors Affecting ◽  
Urea Excretion ◽  
Plasma Urea Concentration ◽  
Filtered Load

The relationships between the plasma urea concentration and clearance variables associated with urinary urea excretion were investigated in urea-supplemented cattle. The plasma urea concentration was related to the urinary urea output, and thus to the urea clearance and the fraction of filtered urea excreted. It is suggested that the urine flow rate was influenced by urinary urea excretion, which in turn was influenced by the plasma urea concentration and therefore by the filtered load of urea. The probable influence of the recycling of urea to the rumen on the excretion of urinary urea is discussed.

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

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.

Factors affecting the urinary excretion of urea nitrogen in cattle. III.* High plasma urea nitrogen concentrations

1972 ◽  
Vol 23 (4) ◽  
pp. 727 ◽  
Author(s):  
RF Thornton ◽  
BW Wilson
Keyword(s):  
Nitrogen Concentration ◽  
High Plasma ◽  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Factors Affecting ◽  
Linear Relationships ◽  
Nitrogen Concentrations ◽  
51Cr Edta ◽  
Filtered Load

The relationship between urinary urea nitrogen excretion, the filtered load of urea nitrogen, and the plasma urea nitrogen concentration were studied in cows intravenously infused with 0.5–10 g urea nitrogen per hour. These levels of infusion resulted in ranges of plasma urea nitrogen concentration of 12–63 mg/100 ml, of filtered urea nitrogen of 3–19 g/hr, and of urinary urea nitrogen excretion of 2.5–12.7 g/hr. There were linear relationships between the filtered load of urea nitrogen and the plasma urea nitrogen concentration (r = 0.91), between urinary urea nitrogen excretion and the filtered load of urea nitrogen (r = 0.92), and between urinary urea nitrogen excretion and the plasma urea nitrogen concentration (r = 0.97). It was concluded that the amount of urea excreted in the urine was regulated more by the plasma urea concentration than by renal processes such as glomerular filtration rate (GFR), the concentrating ability of the kidneys, or urine flow rate. The capacity of the bovine kidneys to excrete urea and mechanisms involved in the renal excretion of urea are discussed. The successful use of 51Cr-EDTA for the estimation of GFR in cattle is reported in an appendix. __________________ *Part II, Aust. J. Agric. Res., 21: 145 (1970).

Renal Response to Changes in Nitrogen Metabolism in Sheep

1958 ◽  
Vol 193 (3) ◽  
pp. 657-661 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Humio Osaki
Keyword(s):  
Nitrogen Metabolism ◽  
Acute Effect ◽  
Regulatory State ◽  
Prolonged Administration ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Low Protein ◽  
Renal Tubular ◽  
Protein Free Diet ◽  
Urea Infusion

The camel has been found to be able to regulate the urea excretion on the renal tubular level. The same was demonstrated in sheep. Lactating or growing sheep, when placed on a low protein diet, decreased the fraction of filtered urea appearing in the urine to very low values. The low urea excretion was characterized by a urea U/P ratio not exceeding 5–7 even at low urine flows. The degree to which urea is concentrated in the urine over the plasma at low urine flows was found to be a good indicator of the regulatory state of the kidney. Changes in this regulatory state could be brought about within approximately one hour. A sudden lowering of the maximum urea U/P was found after a deficient protein-free diet was supplemented with grain. Conversely, a urea infusion raised the maximum urea U/P ratio abruptly in a sheep maintained on a low protein intake. The effect of administration of hydrocortisone or ACTH was studied to determine if these hormones could have a direct effect upon the regulatory state of the kidney. No acute effect was observed. Prolonged administration had in some instances a renal effect. The effect, however, was probably secondary to changes in nitrogen metabolism. The main results are that the excretion of urea is regulated by the renal tubule, that changes in the regulation can take place rapidly following a suitable stimulus, and that these changes are independent of plasma urea level.

Some effects of water restriction on nitrogen metabolism of cattle

1969 ◽  
Vol 20 (1) ◽  
pp. 185 ◽  
Author(s):  
RF Thornton ◽  
NG Yates
Keyword(s):  
Nitrogen Metabolism ◽  
Energy Intake ◽  
Water Intake ◽  
Nitrogen Concentration ◽  
Nitrogen Retention ◽  
Nitrogen Excretion ◽  
Water Restriction ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Faecal Nitrogen

Water restriction was found to decrease nitrogen retention in cattle when compared with periods of similar digestible energy intake but unrestricted water intake. The decreased nitrogen retention was associated with increases in both faecal nitrogen output and urinary urea excretion. The rise in urinary urea nitrogen excretion appeared to be mediated through increased plasma urea nitrogen concentration.

Urea excretion in ruminants. III. The role of the hind-gut (caecum and colon)

1970 ◽  
Vol 21 (2) ◽  
pp. 345 ◽  
Author(s):  
RF Thornton ◽  
PR Bird ◽  
M Somers ◽  
RJ Moir
Keyword(s):  
Terminal Ileum ◽  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Dry Matter Digestibility ◽  
Nitrogen Concentrations ◽  
Faecal Nitrogen ◽  
Hind Gut

The transfer of endogenous nitrogen to the hind-gut digesta of sheep and its relationship with urinary nitrogen excretion were studied concurrently with the estimation of nitrogen balance and of dry matter digestibility in sheep fitted with a re-entrant ileal cannula. Infusion of glucose into the terminal ileum increased the excretion of faecal nitrogen by 1 g/day, while the urinary urea nitrogen excretion decreased by 1 g/day, relative to the respective control levels. Plasma urea nitrogen concentrations remained unchanged. When glucose was infused, the excretion of nitrogen in the faeces was higher than the amount of nitrogen passing the terminal ileum. It is suggested that endogenous urea nitrogen was transferred to the digesta of the hind-gut, where it was incorporated into microbial protein and subsequently excreted in the faeces. The transfer of urea from the blood to either of the fermentative areas of the gut tract is apparently the preferential pathway of urea excretion in ruminants.

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