Effects of intraruminal infusions of urea, sucrose or urea plus sucrose on plasma urea and glucose kinetics in sheep fed chopped lucerne hay

1993 ◽  
Vol 121 (1) ◽  
pp. 125-130 ◽  
Author(s):  
Y. Obara ◽  
D. W. Dellow
Keyword(s):  
Plasma Glucose ◽  
Rumen Fluid ◽  
Glucose Production ◽  
Ammonia Concentration ◽  
Irreversible Loss ◽  
Glucose Kinetics ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Urea Kinetics ◽  
Plasma Urea Concentration

SUMMARYThe effect of rumen fermentation on the relationship between urea and glucose kinetics was examined in sheep fed chopped lucerne hay with intraruminal infusions of water, urea, sucrose, or urea plus sucrose at Palmerston North, New Zealand in 1986. Sheep were fed hourly and infused intraruminally with water (1200 m1/day), or a similar volume containing either urea alone (13·7g/day), sucrose alone (178·2 g/day) or urea (14·6 g/day) plus sucrose (175·0 g/day). The added sucrose resulted in a lower rumen ammonia concentration (P< 0·05), lower plasma urea concentration (P< 0·05) and reduced urinary urea excretion (P< 0·05). Urea recycled to the gut tended to increase with the sucrose, urea or sucrose plus urea treatments compared with the water treatment. The fermentation of sucrose in the rumen resulted in decreases in ruminal pH (P< 0·05) and in the ratio of acetate to propionate (A:P) (P< 0·05). The infusion of sucrose also increased the concentration of propionate in rumen fluid (P< 0·05), tended to increase the plasma glucose level and increased plasma glucose irreversible loss (P< 0·05). The infusion of urea resulted in an increase in the plasma urea level (P< 0·05), urea pool size (P< 0·05) and urea irreversible loss (P< 0·01). However, urea infusion did not affect glucose metabolism or volatile fatty acid (VFA) fermentation. The effects of sucrose infusion on glucose and urea kinetics were broadly similar when given alone or with urea, apart from changes in the urea degradation rate. It was concluded that the additional fermentative activity resulting from sucrose increased propionate production which, in turn, was available for glucose production, thus ‘sparing’ amino acids for tissue protein utilization and reducing urea excretion.

The effect of sucrose supplementation on kinetics of nitrogen, ruminal propionate and plasma glucose in sheep

1996 ◽  
Vol 126 (1) ◽  
pp. 99-105 ◽  
Author(s):  
M. Sutoh ◽  
Y. Obara ◽  
S. Miyamoto
Keyword(s):  
Production Rate ◽  
Plasma Glucose ◽  
Transfer Rate ◽  
Loss Rate ◽  
Nitrogen Retention ◽  
Ammonia Nitrogen ◽  
Irreversible Loss ◽  
Plasma Urea ◽  
Plasma Urea Concentration ◽  
Kinetics Of

SUMMARYThe effects of dietary sucrose on the metabolic rate of plasma glucose and ruminal propionate as well as the change in nitrogen kinetics were examined in four mature wethers fitted with rumen fistulas in Tsukuba, Japan in 1990. Wethers were fed at 12 equal intervals daily on crushed lucerne hay cubes (1233 g DM/day), with or without 204 g/day of sucrose. Plasma urea and glucose kinetics were determined following a single intravenous injection of [I5N]urea and [U-13C]glucose respectively; and the kinetics of ruminal ammonia and propionate were determined following a single intraruminal injection of [15N]ammonium chloride and [2–13c]sodium propionate respectively. Following supplementation of sucrose to the diet, nitrogen retention was increased (P< 0·05) with a decrease in plasma urea concentration (P< 0·05) and urinary urea excretion (P< 0·05). Sucrose supplementation decreased (P< 005) the concentration and irreversible loss rate of ruminal ammonia. Urinary allantoin excretion did not change with sucrose treatment, but the flow rate of non-ammonia-nitrogen from the rumen was increasedP< 0·05). The transfer rate of ruminal ammonia to plasma urea was also decreased (P< 0·01), whilst the transfer rate of plasma urea to ruminal ammonia was increased (P< 0·05) by dietary sucrose. Sucrose supplementation resulted in a higher concentration of propionate and butyrate (P< 0·05) in the rumen with no significant change in acetate or pH. The concentration of plasma glucose did not change with sucrose treatment, but the concentration of insulin, pool size (P< 0·05) and the irreversible loss rate of glucose (P< 0·01) were increased, reflecting the increase in the production rate of ruminal propionate (P< 0·05). It was concluded that the supplementation of sucrose affected the metabolism of urea and glucose in plasma via a change in ruminal production rate of ammonia and propionate, respectively.

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.

Biochemical Aspects and Clinical Perspectives of Continuous Urea Monitoring in Plasma Ultrafiltrate: Preliminary Results of a Multicenter Study

1995 ◽  
Vol 18 (9) ◽  
pp. 544-547 ◽  
Author(s):  
G. Colasanti ◽  
G. Arrigo ◽  
A. Santoro ◽  
S. Mandolfo ◽  
C. Tetta ◽  
...  
Keyword(s):  
Laboratory Method ◽  
Mean Difference ◽  
Limits Of Agreement ◽  
Laboratory Plasma ◽  
Plasma Urea ◽  
Urea Kinetics ◽  
On Line ◽  
The Mean ◽  
Plasma Urea Concentration

We tested a new biosensor for urea monitoring in the ultrafiltrate during PFD in a group of 5 hemodialyzed stable patients. The inspection of the UF-urea profile reflects the dynamical changes of the plasma urea concentration during diffusive dialysis and allows the fitting of the main mathematical models of urea kinetics. The biosensor efficiency was 98.4% on average (SD: 1.5%) at Uf fluxes varying from 45 to 55 ml/min (mean: 51 ml/min; SD: 3.2) and at Uf-urea concentrations varying from 23 to 165 mg/dl. The mean difference between Uf-urea determined by the laboratory method and Uf-urea assayed by the biosensor was -1.07 mg/dl and the 95% confidence interval ranged from -2.01 to 0.13 mg/dl. The mean difference between laboratory plasma urea and Uf-urea from the biosensor was on average -1.9 mg/dl and the estimated limits of agreement with a confidence of 95% were -3.16 and 0.64 mg/dl. Comparison between kinetic models and experimental profiles of plasma urea decrease, evaluations of recirculation and post-dialytic rebound, the role of Kt/V on-line during dialysis were the preliminary clinical applications of this biosensor.

Effects of Trichostrongylus colubriformis (Nematoda) on the nutrition and metabolism of sheep. II.* Metabolism of urea

1974 ◽  
Vol 25 (2) ◽  
pp. 363 ◽  
Author(s):  
FB Roseby ◽  
RA Leng
Keyword(s):  
Amino Acids ◽  
Urinary Excretion ◽  
Production Rate ◽  
Feed Intake ◽  
Loss Rate ◽  
Single Injection ◽  
Irreversible Loss ◽  
Trichostrongylus Colubriformis ◽  
Plasma Urea ◽  
Plasma Urea Concentration

The effect of infection with Trichostrongylus colubriformis on the rates of production, excrehon and recycling of urea was studied in 24 Merino lambs. The production rate of urea was estimated as the irreversible loss rate of [14C]urea given as a single injection. The feed intake of all sheep was maintained at 540 g/day throughout the experiment. Parasitized sheep had a higher plasma urea concentration than their paired controls 15–35 days after they were infected. This was associated with an increase in the rate of irreversible loss and the rate of urinary excretion of urea. The additional urea lost in urine is apparently produced from ammonia released from amino acids in the tissues or in the digestive tract. ______________________ *Part I, Aust. J. Agric. Res., 24: 947 (1973).

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.

Influence of somatostatin on glucagon- and epinephrine-stimulated hepatic glucose output in the dog.

1979 ◽  
Vol 236 (2) ◽  
pp. E113
Author(s):  
L Saccà ◽  
R Sherwin ◽  
P Felig
Keyword(s):  
Plasma Glucose ◽  
Glucose Production ◽  
Conscious Dogs ◽  
Insulin Deficiency ◽  
Hepatic Glucose Output ◽  
Glucose Kinetics ◽  
Insulin Levels ◽  
Hepatic Glucose ◽  
Glucose Output ◽  
Insulin Replacement

Glucose kinetics were measured using [3-3H]glucose in conscious dogs during the infusion of: 1) glucagon alone; 2) glucagon plus somatostatin with insulin replacement; 3) epinephrine alone; and 4) epinephrine plus somatostatin with insulin and glucagon replacement. Infusion of glucagon alone resulted in a 10-15 mg/dl rise in plasma glucose and a transient 45% rise in glucose production. When somatostatin and insulin were added, a four- to fivefold greater rise in plasma glucose and glucose production was observed. Glucagon levels were comparable to those achieved with infusion of glucagon alone, whereas peripheral insulin levels increased three- to fourfold above baseline, suggesting adequate replacement of preinfusion portal insulin levels. Infusion of epinephrine alone produced a 40% rise in plasma glucose and a 100% rise in glucose production. When somatostatin, insulin, and glucagon were added to epinephrine, the rise in glucose production was reduced in 65% despite replacement of glucagon levels and presumably mild portal insulin deficiency. These findings suggest that somatostatin: 1) potentiates the stimulatory effect of physiologic hyperglucagonemia on glucose production independent of insulin availability and 2) blunts the stimulatory effect of physiologic increments of epinephrine independent of glucagon availability.

Urea excretion in ruminants. II. Studies in sheep whose rumen contents were replaced with physiological saline

1970 ◽  
Vol 21 (2) ◽  
pp. 337 ◽  
Author(s):  
RF Thornton
Keyword(s):  
Maximum Concentration ◽  
Close Association ◽  
Physiological Saline ◽  
Urine Flow ◽  
Urea Concentration ◽  
Nitrogen Accumulation ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Plasma Urea Concentration

Urea was infused intravenously into sheep whose rumen contents were removed and replaced with physiological saline. Despite large differences in plasma urea concentration the rate of nitrogen accumulation in the rumen, as urea plus ammonia, was similar at 6-7 mmoles/hr. The maximum concentration of nitrogen, as urea plus ammonia, was not influenced by plasma urea concentrations higher than 15-17 mg N/100 ml. Urinary urea excretion was positively related to plasma urea concentration but within any level of plasma urea concentration there was a close association between urine flow and urinary urea excretion.

scholarly journals Effects of Somatostatin and Glucagon on the Utilization of [2_14C] Propionate in Glucose Production in Vivo in Sheep

1980 ◽  
Vol 33 (4) ◽  
pp. 457 ◽  
Author(s):  
Ronald P Brockman ◽  
Cindy Greer
Keyword(s):  
Continuous Infusion ◽  
Plasma Glucose ◽  
Control Period ◽  
Specific Radioactivity ◽  
Glucose Production ◽  
Irreversible Loss ◽  
Selective Effect ◽  
Glycogenolytic Effect ◽  
Glucose Synthesis

This study examined the effects of hypoglucagonaemia and hyperglucagonaemia on the incorporation of 14C from [2-14C]propionate into plasma glucose of sheep in vivo. The sheep were adult ewes fed a maintenance diet of lucerne pellets delivered in equal aliquots hourly. The irreversible loss of glucose was determined by the continuous infusion of [6-3H]glucose. During the control period (the hour immediately preceding infusion of hormones) 63 �2 % of the propionate was converted to glucose, accounting for 30�2 % of glucose production. Glucagon deficiency, induced by infusion of somatostatin (100 J1g/h), did not affect gluconeogenesis and the irreversible loss of glucose significantly. However, glucagon infusion at 11 �5 �O� 6 J1g/h significantly increased the irreversible loss of glucose, with the greatest increase occurring in the first 15 min of infusion. The 14C specific radioactivity of glucose and the fraction of glucose derived from propionate decreased significantly during glucagon infusion. The data are consistent with glucagon having a marked glycogenolytic effect initially, but little or no selective effect in promoting the utilization of propionate for glucose synthesis in vivo in sheep.

Urea excretion in ruminants. I. Studies in sheep and cattle offered the same diet

1970 ◽  
Vol 21 (2) ◽  
pp. 323 ◽  
Author(s):  
RF Thornton
Keyword(s):  
Body Size ◽  
Urinary Excretion ◽  
Urine Flow ◽  
Lower Plasma ◽  
Plasma Urea ◽  
Urea Excretion ◽  
Consequent Reduction ◽  
Renal Tubular ◽  
Plasma Urea Concentration ◽  
Cattle And Sheep

Cattle and sheep were offered the same diet in amounts according to the ratio of their metabolic body size, and were intravenously infused with urea in amounts according to the same ratio. An apparent limit to the transfer of urea from the blood to the rumen occurred at lower plasma urea and rumen ammonia concentrations in cattle than in sheep. Associated with ingestion of feed there was a decline in the concentrations of both rumen ammonia and plasma urea, and in urinary urea excretion. It is suggested that (a) the transfer of urea from the blood to the rumen and the urinary excretion of urea are reciprocally related, and (b) the transfer of urea from the blood to the rumen and the consequent reduction in plasma urea concentration associated with feed ingestion may account for the decline in urinary urea excretion after ingestion of feed, rather than changes in the urine flow rate and in renal tubular mechanisms.

Digestive and metabolic effects of altering feeding frequency in athletic horses

2006 ◽  
Vol 3 (2) ◽  
pp. 83-91 ◽  
Author(s):  
A Jansson ◽  
A Sandin ◽  
JE Lindberg
Keyword(s):  
Glucose Metabolism ◽  
Plasma Glucose ◽  
Plasma Insulin ◽  
Urea Concentration ◽  
Feeding Frequency ◽  
Plasma Urea ◽  
Post Exercise ◽  
Intensive Exercise ◽  
Low Levels ◽  
Plasma Urea Concentration

AbstractThe aim of this study was to investigate the effect of feeding frequency on total tract digestibility and plasma glucose, insulin, urea, gastrin and cortisol concentrations at rest and following exercise in seven Standardbred horses in race training. The horses were fed every 12 h (twice a day, 2TD) and every 4 h (six times a day, 6TD) for 25 days, in a cross-over design. The diet (64% grass hay, 36% concentrates on weight basis) was fed at twice the maintenance energy requirement. Blood samples were taken every hour for 24 h on day 17, total collection of urine and faeces was made on days 19–21 and an intensive exercise test was performed on day 25. Altering feeding frequency caused small variations in diurnal plasma glucose, urea, gastrin and cortisol concentrations and did not affect total tract nutrient digestibility. There was an increase in the mean diurnal plasma urea concentration on the 2TD regime and low levels of plasma insulin were observed 7 h after feeding 2TD. The response to intensive exercise on heart rate, plasma lactate and plasma glucose was similar on both treatments but the plasma insulin concentration was higher following exercise in the 2TD regime, indicating that post-exercise glucose metabolism was altered. In conclusion, this study shows that feeding athletic horses only 2TD caused metabolic signs resembling those observed during feed deprivation (low levels of plasma insulin and an increased diurnal plasma urea concentration) and an altered post-exercise glucose metabolism, but did not affect the digestive response.

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