The effects of increased nitrogen intakes on plasma urea nitrogen and rumen ammonia levels in sheep

1970 ◽  
Vol 21 (3) ◽  
pp. 501 ◽  
Author(s):  
KH McIntyre
Keyword(s):  
Dry Matter ◽  
Nitrogen Excretion ◽  
Kidney Tubules ◽  
Urea Clearance ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Nitrogen Intake ◽  
Ad Libitum ◽  
Excretion Rates

A series of five roughage rations providing increasing amounts of nitrogen (6.8, 16.8, 23.5, 37.3, and 46.3 g/day) and some changes in dry matter intakes (720, 710, 704, 1056, and 1408 g/day) was offered to sheep. The first four rations were given hourly and the fifth ad libitum. Urine outputs, urine total nitrogen, urine urea nitrogen, and urea clearance values increased with nitrogen intakes. Water intakes were linearly related to dry matter intakes. Plasma urea nitrogen and rumen ammonia levels both increased linearly to about 30 mg/100 ml, but did not increase further on higher levels of nitrogen intake. At these levels of intake both plasma urea nitrogen and rumen ammonia levels were no longer related to urine nitrogen excretion rates. The results are discussed in relation to the role of the kidney tubules in nitrogen excretion in the sheep.

scholarly journals Plasma urea nitrogen as an indicator of amino acid imbalance in rabbit diets

2020 ◽  
Vol 28 (2) ◽  
pp. 63
Author(s):  
Pablo Jesús Marín-García ◽  
María del Carmén López-Luján ◽  
Luís Ródenas ◽  
Eugenio Melchor Martínez-Paredes ◽  
Enrique Blas ◽  
...  
Keyword(s):  
Amino Acid ◽  
Feed Efficiency ◽  
Dry Matter ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Dietary Amino Acid ◽  
Amino Acid Imbalance ◽  
Ad Libitum ◽  
Amino Acid Balance ◽  
Current Guidelines

<p>In recent decades, recommendations on dietary protein content have been considerably reduced, while fibre content has been increased. Under these conditions, an adequate dietary amino acid balance could be crucial to optimise feed efficiency. Plasma urea nitrogen (PUN) level could be a good indicator of an amino acid imbalance and its potential has already been studied in other species, but not yet in rabbits. The main objective of the present work was to detect the possible interest of PUN in pinpointing amino acid deficiencies in rabbits. Two experimental diets were formulated from the same basal mixture, following all the recommendations for growing rabbits, except lysine, whose content was variable, following current guidelines in diet P8.1 or lower from those in P4.4 (with 8.1 and 4.4 g/kg dry matter of lysine and with 757 and 411 mg of lysine per MJ of digestible energy). Three different trials were designed: one where the animals were fed &lt;em&gt;ad libitum&lt;/em&gt; (AL) and two others in which fasting periods of 10 h were included; one where feeding was restored at 08:00 h (Fast8h) and the other at 18:00 h (Fast18h). A total of 72 three-way crossbred growing rabbits (24 animals for each trial in a split-plot trial) up to a total of 12 recordings were used. Blood samples were taken every 4 h in AL trial and every hour after refeeding up to a total of six controls, in trials Fast8h and<br />Fast18h. The differences between balanced and unbalanced diets in lysine were highest (&lt;em&gt;P&lt;/em&gt;&lt;0.001) between 04:00 h and 12:00 h in animals fed ad libitum, and at 3 h after refeeding (21:00 h) in Fast18h. These results suggest that PUN could be an adequate indicator to detect deficiencies in amino acids in growing rabbit<br />diets.</p>

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.

Urea Excretion in the Camel

1957 ◽  
Vol 188 (3) ◽  
pp. 477-484 ◽  
Author(s):  
Bodil Schmidt-Nielsen ◽  
Knut Schmidt-Nielsen ◽  
T. R. Houpt ◽  
S. A. Jarnum
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Urea Concentration ◽  
Nitrogen Excretion ◽  
Renal Tubules ◽  
Urea Clearance ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Plasma Urea Concentration

The nitrogen excretion was studied in the one-humped camel, Camelus dromedarius. When a growing camel was maintained on a low N intake (dates and hay) the amount of N excreted in the form of urea, NH3 and creatinine decreased to 2–3 gm/day. This decrease was caused by a drop in urea excretion from 13 gm to 0.2–0.5 gm/day. Urea given intravenously during low N intake was not excreted but was retained. (The camel like other ruminants can utilize urea for microbial synthesis of protein.) The renal mechanism for urea excretion was investigated by measuring urea clearance and glomerular filtration rate during a period of 7 months. During normal N intake about 40% of the urea filtered in the glomeruli were excreted in the urine while during low N intake only 1–2% were excreted. The variations in urea clearance were independent of the plasma urea concentration and of glomerular filtration rate, but were related to N intake and rate of growth. No evidence of active tubular reabsorption of urea was found since the urine urea concentration at all times remained higher than the simultaneous plasma urea concentration. The findings are not in agreement with the current concept for the mechanism of urea excretion in mammals. It is concluded that the renal tubules must either vary their permeability to urea in a highly selective manner or secrete urea actively.

scholarly journals Effects of Decreasing Dietary Crude Protein Level on Growth Performance, Nutrient Digestion, Serum Metabolites, and Nitrogen Utilization in Growing Goat Kids (Capra. hircus)

Animals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 151 ◽  
Author(s):  
Wen Zhu ◽  
Wei Xu ◽  
Congcong Wei ◽  
Zijun Zhang ◽  
Chunchao Jiang ◽  
...  
Keyword(s):  
Growth Performance ◽  
Crude Protein ◽  
Dry Matter ◽  
Nitrogen Utilization ◽  
Nitrogen Excretion ◽  
Capra Hircus ◽  
Serum Metabolites ◽  
Dietary Crude Protein ◽  
Nutrient Digestion ◽  
Nitrogen Intake

The effects of decreasing dietary crude protein (CP) level on growth performance, nutrient digestion, serum metabolites, and nitrogen utilization in growing goat kids were investigated in the current study. Thirty-six male Anhui white goat kids were randomly assigned to one of three CP content diets: 14.8% (control), 13.4%, and 12.0% of dry matter, respectively. Diets were isoenergetic. The experiment lasted for 14 weeks, with the first two weeks being for adaptation. Results showed that the low-CP diet decreased average daily gain, feed efficiency, digestibility of dry matter, organic matter, crude protein, and fiber. No significant changes were observed in dry-matter intake. With a decrease in dietary CP level, fecal nitrogen excretion (% of nitrogen intake) increased linearly, whereas CP intake, blood urea nitrogen, urinary nitrogen excretion (% of nitrogen intake), and total nitrogen excretion (% of nitrogen intake) decreased. Serum glucose concentration decreased, while concentrations of low-density lipoproteins and non-esterified fatty acids increased with the low-CP diet. In conclusion, decreasing the dietary CP level decreased goats’ nitrogen excretion, but with restrictive effects on growth performance. A diet containing 13.4% CP is optimal for reducing nitrogen excretion without any adverse effect on growth performance of Anhui white goat kids. This concentration is 1.4% points lower than the NRC recommendations and thus is also environmentally beneficial on the input side because it decreases the use of feed (soy) protein.

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 Evaluation of Urinary Nitrogen Excretion from Plasma Urea Nitrogen in Dry and Lactating Cows

2008 ◽  
Vol 21 (8) ◽  
pp. 1159-1163 ◽  
Author(s):  
S. Kume ◽  
K. Numata ◽  
Y. Takeya ◽  
Y. Miyagawa ◽  
S. Ikeda ◽  
...  
Keyword(s):  
Nitrogen Excretion ◽  
Urea Nitrogen ◽  
Plasma Urea ◽  
Lactating Cows ◽  
Urinary Nitrogen Excretion ◽  
Urinary Nitrogen

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.

Prerenal Azotemia: Differentiation of Hyperureagenesis from Renal Hypoperfusion Using Urinary Urea Nitrogen Data

1996 ◽  
Vol 19 (3) ◽  
pp. 164-169 ◽  
Author(s):  
A.H. Sklar ◽  
L.A. Riesenberg ◽  
A. UR Rehman ◽  
S. Smith ◽  
H. Rivera-Padilla
Keyword(s):  
Serum Creatinine ◽  
Creatinine Clearance ◽  
Laboratory Data ◽  
Nitrogen Excretion ◽  
Cross Sectional ◽  
Urea Nitrogen ◽  
Group I ◽  
Group Ii ◽  
Excretion Rates ◽  
Renal Hypoperfusion

Blood urea nitrogen (BUN) rises disproportionately to serum creatinine in patients with prerenal azotemia whether due to impaired hemodynamics or excessive ureagenesis. To determine whether urinary urea nitrogen excretion rates can distinguish between these causes of hyperuremia we performed a cross-sectional observational study to compare urinary urea nitrogen excretion rates in a highly selected group of patients with prerenal azotemia. Patients who had stable serum creatinine levels, BUN: serum creatinine ratios exceeding 20:1, and progressive azotemia were identified from the hospital laboratory data base. Using conventional clinicolaboratory criteria, 27 patients were diagnosed with either renal hypoperfusion (group I; n = 17) or hyperureagenesis ((group II; n = 10). Random urine sampling for electrolytes, osmolality, creatinine, and urea nitrogen was followed by 24 h collection for creatinine clearance and urinary urea nitrogen. There were no significant differences in age, gender, absolute levels of BUN, or BUN: serum creatinine ratios between the groups. Creatinine clearance (ml/min/1.73 m2) (ml/s/1.73 m2) was lower in group I than in group II (21 ± 16 vs. 36 ± 13; p<0.05) (0.35 ± 0.27 vs. 0.60 ± 0.22; p < 0.05). Twenty-four hour urinary urea nitrogen levels were significantly different (group I, 4.8 ± 2.9 vs. group II, 13.6 ± 3.2 gm; p < 0.001) (group I, 171 ± 300 vs. group II, 486 ± 114 mmol; p < 0.001). Random urine urea excretion indices were less discriminating but nevertheless still capable of separating the groups. Timed as well as random urine urea nitrogen determinations may assist in differentiating prerenal azotemia due to renal hypoperfusion from hyperureagenesis. Differentiation of these causes of prerenal azotemia might prevent iatrogenic overhydration of patients with azotemia incorrectly attributed to hemodynamic disturbances.

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