scholarly journals Foetal and maternal rates of urea production and disposal in well-nourished and undernourished sheep

1982 ◽  
Vol 48 (1) ◽  
pp. 49-58 ◽  
Author(s):  
J. C. Hodgson ◽  
D. J. Mellor ◽  
A. C. Field
Keyword(s):  
Live Weight ◽  
Close Correlation ◽  
Entry Rate ◽  
Jugular Veins ◽  
Plasma Urea ◽  
Indwelling Catheters ◽  
Dietary Nitrogen ◽  
Pregnant Sheep ◽  
Urea Production ◽  
Series Of Experiments

1. Five monotocous and twoditocous Scottish Blackface ewes with indwelling catheters in an umbilical artery and vein of one foetus only and in both maternal jugular veins were used.2. Experiments were conducted over a period of 2 d when [I4C]urea was infused intravenously over 9 h into either the mother or foetus, separate days being used for each infusion. Two series of experiments were completed, one in well-nourished and the other in undernourished sheep at 125–141) and 138–143 d of gestation respectively.3. Plasma urea specific radioactivities of the mother and infused foetus at plateau were used to determine the urea flux-rates within and between mother and foetus. The mean rate of foetal urea production (Ffo) was 1.45 and 1.63 mg/min per kg foetus in well-nourished and undernourished ewes respectively. The corresponding rates of maternal urea production (Fmo) were 0.49 and 0.37 mg/min per kg live weight respectively and there was a close correlation between the rate of maternal urea disposal (Fom) and the dietary nitrogen intake.4. The values of Ffo were used to calculate the maximum potential for foetal gluconeogenesis from deaminated amino acids. These calculations were compared with published information on the over-all rates of foetal gluconeo genesis in well-nourished ewes.5. The foetal entry rate of urea expressed on a body-weight basis was high, approximately 8.5 times that of the mother, but it was a threefold overestimate of Ffo. The maternal entry rate was 1.3 times Fmo and the significance of this in relation to assessing differences in urea entry rates in pregnant and non-pregnant sheep is discussed.

Nitrogen metabolism and recycling in yaks (Bos grunniens) offered a forage - concentrate diet differing in N concentration

2012 ◽  
Vol 52 (5) ◽  
pp. 287 ◽  
Author(s):  
X. S. Guo ◽  
Y. Zhang ◽  
J. W. Zhou ◽  
R. J. Long ◽  
G. S. Xin ◽  
...  
Keyword(s):  
Latin Square ◽  
Urea Clearance ◽  
Entry Rate ◽  
Plasma Urea ◽  
Urea Production ◽  
Use Efficiency ◽  
Four Levels ◽  
N Use ◽  
Microbial N ◽  
Incremental Increase

An experiment was conducted to characterise N use efficiency and quantify urea fluxes in yaks offered four levels of dietary N (1.43%, 1.97%, 2.45% and 2.90% of diet DM) in a 4 × 4 Latin square design. The incremental increase in N intake linearly increased N retention (P = 0.003) and the excretion of urinary N (P < 0.001), but no difference (P > 0.05) in faecal N excretion was observed in growing yaks fed any of the four diets. Microbial N production had quadratic (P < 0.001) responses to dietary N, characterised by the highest microbial N production occurring in the 1.97% N diet (P < 0.05). As the N content of the diet increased, the urinary excretion of urea increased from 13% to 27% of urea entry rate (quadratic, P < 0.001), whereas gastrointestinal entry urea returned to ornithine cycling decreased from 46% to 40% (linear, P < 0.001), and the gastrointestinal entry urea used for anabolism increased from 50% to 56% (linear, P < 0.001). Gastrointestinal entry urea incorporated into bacterial N decreased linearly (P < 0.001) with incremental increase in N intake, and the greatest concentration (23.5%) of bacterial N originating from plasma urea N was in yaks fed the 1.43% N diet. As much as 87% of the urea synthesised in the liver was returned to the gastrointestinal tract when the yaks were fed a diet with 1.43% N (1.1 times the maintenance N level). Moreover, constantly greater urea production than the intake of digestible N, and the gastrointestinal-urea clearance than the kidney-urea clearance were observed, respectively, in the growing yaks, regardless of the level of N intake. These results suggest that yaks might be more efficient at utilising N under harsh environment than are cattle.

scholarly journals Metabolism of urea in late pregnancy and the possible contribution of amino acid carbon to glucose synthesis in sheep

1970 ◽  
Vol 24 (4) ◽  
pp. 905-915 ◽  
Author(s):  
J. V. Nolan ◽  
R. A. Leng
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Late Pregnancy ◽  
Pool Size ◽  
Entry Rate ◽  
Plasma Urea ◽  
Upper Limit ◽  
Pregnant Sheep ◽  
Potential Availability ◽  
Glucose Synthesis

1. Metabolism of urea in non-pregnant and pregnant sheep (1–25 d from term) has been examined. Injections of [14C]urea were used to estimate urea entry rate, urea pool size and urea space in sheep given 1000 g of a diet of equal parts of crushed oats and chaffed lucerne hay (daya) and in the same sheep 4 d after the ration had been reduced to 250 g (dayb).2. On both experimental days (aandb), mean pool size was greater (14% on day α, 29% on dayb) and urea space was greater (54% on day α, 24% on dayb) in pregnant animals than in non-pregnant animals; mean plasma urea concentrations were lower (35%) in the pregnant animals on day a but were not significantly different on dayb.3. The entry rate of urea was similar in all the animals on daya, but was significantly higher (34%) in pregnant than in non-pregnant animals on dayb. There was a significant decrease in urea entry rate in both pregnant (33%) and non-pregnant (86%) animals on dayb.4. The rate of excretion of urea was lower (26% on daya, 35% on dayb) in pregnant animals, indicating a higher (31% on day α, 40% on dayb) rate of degradation of urea in the digestive tract of pregnant as compared with non-pregnant sheep.5. Measurements of urea entry rate have been used to calculate the upper limit of amino acid deamination in pregnant and non-pregnant sheep, and this has been used as an indication of the potential availability of amino acid carbon for glucose synthesis. It is suggested that, at a maximum, amino acids may have contributed the carbon required for 63 g/d and 52 g/d of glucose on daysaandbrespectively.

Patterns of Response of Some Physiological Indices of Stress in Pigs Negotiating Loading Ramps

1993 ◽  
Vol 1993 ◽  
pp. 84-84
Author(s):  
S.N. Brown ◽  
T.G. Knowles ◽  
J.L. McKinstry ◽  
J.E. Edwards ◽  
M.H. Anil ◽  
...  
Keyword(s):  
Time Course ◽  
Live Weight ◽  
Sampling Procedure ◽  
Blood Sampling ◽  
Jugular Veins ◽  
Indwelling Catheters ◽  
Blood Samples ◽  
Whole Process ◽  
Physiological Indices

Many reports have examined the effect of subjecting animals to stress and a variety of physiological indices have been used to monitor their responses. The indices are often only measured at one point in time and compared to resting levels. Problems could arise in interpretation of the results especially where there is little or no information on the time course of response. This work examined the pattern or response of various indices to the stress of negotiating a loading ramp.Four pigs of approximately 60 kg live weight were surgically prepared and indwelling catheters placed in both jugular veins. The animals were allowed to recover for three days and to become accustomed to the blood sampling procedure before the experiment. The pigs were driven individually up a 2.44m long ramp which was set at an angle of 34° lo the horizontal, the maximum allowed under UK legislation for internal vehicle ramps (Transport of Animals (Road and Rail) Order, 1975). Nine blood samples were removed at intervals from each pig. The whole process was repealed on each individual pig for three days.

UREA DEGRADATION IN THE CAMEL

1976 ◽  
Vol 56 (3) ◽  
pp. 595-601 ◽  
Author(s):  
B. EMMANUEL ◽  
B. R. HOWARD ◽  
M. EMADY
Keyword(s):  
Crude Protein ◽  
Urea Concentration ◽  
Pool Size ◽  
Entry Rate ◽  
Plasma Urea ◽  
Dietary Nitrogen ◽  
Urea Metabolism ◽  
Plasma Urea Concentration ◽  
Kinetics Of ◽  
General Plasma

Following a single injection of 14C-urea, the kinetics of urea metabolism have been studied in two female Arabian camels (Camelus dromedarius) fed roughage diets containing 6.1 (diet A), 9.6 (diet B), and 13.6% (diet C) crude protein. In general, plasma urea concentration, urea pool size, urea entry rate and urinary urea excretion rate increased as the dietary nitrogen intake increased. The mean extents of urea degradation were approximately 86, 74 and 47% for diets A, B, and C, respectively, as calculated from the ratio of urea degradation rate to urea entry rate, or from the fraction of 14C-urea recovered in the urine. The following parameters were linearly related: urea entry rate and urea pool size, urea pool size and plasma urea concentration, percentage urea degraded and urea entry rate, and percentage urea degraded and crude protein intake.

scholarly journals Effect of abomasal glucose infusion on alanine metabolism and urea production in sheep

2000 ◽  
Vol 84 (2) ◽  
pp. 157-163 ◽  
Author(s):  
T. Obitsu ◽  
D. Bremner ◽  
E. Milne ◽  
G. E. Lobley
Keyword(s):  
Amino Acids ◽  
Body Weight ◽  
Branched Chain Amino Acids ◽  
Flux Rate ◽  
Plasma Urea ◽  
Exogenous Glucose ◽  
Abomasal Infusion ◽  
Urea Production ◽  
Branched Chain ◽  
N Flux

The effect of abomasal infusion of glucose (120 kJ/d per kg body weight (BW)0·75, 758 mmol/d) on urea production, plasma alanine-N flux rate and the conversion of alanine-N to urea was studied in sheep offered a low-N diet at limited energy intake (500 kJ/d per kg BW0·75), based on hay and grass pellets. Glucose provision reduced urinary N (P= 0·040) and urea (P= 0·009) elimination but this was offset by poorer N digestibility. Urea-N production was significantly reduced (822v. 619 mmol/d,P= 0·024) by glucose while plasma alanine-N flux rate was elevated (295v. 342 mmol/d,P= 0·011). The quantity of urea-N derived from alanine tended to be decreased by glucose (127v. 95 mmol/d) but the fraction of urea production from alanine was unaltered (15 %). Plasma urea and alanine concentrations (plus those of the branched chain amino acids) decreased in response to exogenous glucose, an effect probably related to enhanced anabolic usage of amino acids and lowered urea production.

scholarly journals Modulation of electrolyte homeostasis by dietary nitrogen intake in growing goats

2011 ◽  
Vol 105 (11) ◽  
pp. 1619-1626 ◽  
Author(s):  
Alexandra S. Muscher ◽  
Marion Piechotta ◽  
Gerhard Breves ◽  
Korinna Huber
Keyword(s):  
Type I Collagen ◽  
Young Male ◽  
Renal Elimination ◽  
Type I ◽  
Plasma Urea ◽  
Dietary Nitrogen ◽  
Electrolyte Homeostasis ◽  
Growing Goats ◽  
Ca Homeostasis ◽  
Total Alkaline

In goats, the combination of dietary N and Ca reduction caused hypocalcaemia and further changes in Ca homeostasis. The aim of the present study was to characterise the effects of dietary N reduction under normocalcaemia on mineral and bone metabolism in young goats. Young male goats of the Saanen breed were fed a diet reduced in N (8 %) for about 7 weeks (ten animals per group) and were compared with goats fed with an adequate N (14 %) diet. When N intake was reduced in young goats, plasma urea concentrations as well as renal elimination of urea were reduced. This was inversely related to creatinine in plasma and urine, which increased during a dietary N reduction as a function of reduced renal activity to save urea during N scarcity. During this decrease in renal function, associated with declined insulin-like growth factor 1 concentrations, a reduction in calcidiol and calcitriol concentrations could be observed. Meanwhile, carboxyterminal cross-linked telopeptide of type I collagen values and activity of total alkaline phosphatase were both elevated, indicating some bone remodelling processes taking place during a reduced N diet in young goats. The concentrations of inorganic phosphate (Pi) and total Ca were changed in several body fluids, indicating that Piand Ca homeostasis was perturbed in goats fed a reduced N diet. Therefore, more research is needed to find the balance between reduction of environmental N pollution by reducing dietary N in ruminant feeding and maintaining the animal's health.

scholarly journals Non-esterified Long-chain Fatty Acid Metabolism in Fed Sheep at Rest and During Exercise

1987 ◽  
Vol 40 (2) ◽  
pp. 221 ◽  
Author(s):  
DW Pethick ◽  
N Harman ◽  
JK Chong
Keyword(s):  
Skeletal Muscle ◽  
Ketone Bodies ◽  
Long Chain Fatty Acids ◽  
Entry Rate ◽  
Long Chain Fatty Acid ◽  
Pregnant Sheep ◽  
Arteriovenous Difference ◽  
Long Chain ◽  
Sustained Increase

The role of circulating, non-esterified, long-chain fatty acids (NEFA) as a source of energy for the whole animal and skeletal muscle was investigated in fed non-pregnant sheep at rest and during exercise. Infusion of tracer quantities of [1-14C]oleic or [l-14C]stearic acid was combined with the use of arteriovenous difference studies on fed sheep at rest or during a 2 h period of exercise on a belt treadmill moving at 4� 5 km h -I. At rest all parameters of NEFA metabolism indicated a minimal role for oxidation. Thus the concentration in plasma (0'07 � 0�01 mmol I-I), entry rate (0'08 � 0�02 mmol h- I kg-I body wt), contribution to whole animal oxidation (1'2 � 0'3%) and utilization of NEFA by skeletal muscle (0'046 � 0�008 mmol h- I kg-I muscle) were all low. Exercise prompted a shift to lipolysis and accordingly the above parameters increased markedly some 13-24-fold. The circulating concentration of ketone bodies showed only a small increase during exercise and consequently the role of ketone bodies as an energy source during exercise was minimal. Glucose utilization by skeletal muscle was considerable in animals at rest and it represented the most significant potential fuel of skeletal muscle. Exercise resulted in a sustained increase of 3-4-fold in the utilization of glucose by skeletal muscle. Thus the traditional view that NEF A and not glucose is a predominant fuel of skeletal muscle of fed sheep should be appraised.

Aspects of nitrogen utilization in Asiatic water buffalo and Zebu cattle

1983 ◽  
Vol 100 (1) ◽  
pp. 13-23 ◽  
Author(s):  
J. B. Moran
Keyword(s):  
Nitrogen Balance ◽  
Water Buffalo ◽  
Energy Content ◽  
Live Weight ◽  
Metabolizable Energy ◽  
Nitrogen Excretion ◽  
Zebu Cattle ◽  
Dietary Nitrogen ◽  
Faecal Nitrogen ◽  
Urinary Nitrogen

SUMMARYThe results of 62 comparative digestibility and nitrogen balance trials of Asiatic water buffalo and Zebu cattle fed the same roughage or mixed diet were analysed to test for species differences in various nitrogen input-output relationships. The influence of dietary metabolizable energy content on the utilization of dietary or apparently digested nitrogen (ADN) was also investigated.There was no difference between buffaloes and Zebus in their ability to digest dietary nitrogen. The true nitrogen digestibility was calculated to be 81% and the metabolic faecal nitrogen excretion to be 0·36 g N/lOOg dry-matter intake. The buffaloes had lower rates of excretion of urinary nitrogen per unit increase in ADN, and at the same intake of ADN (143 mg/kg live weight/day), they had the higher nitrogen balance: 58v.48 mg/kg live weight/day. Dietary metabolizable energy content did not affect the utilization of digested nitrogen.Estimates of metabolic faecal nitrogen and endogenous urinary nitrogen excretions and of maintenance requirements for digested nitrogen were similar to those of tropical large ruminants reported by other workers. On low-quality (0·8% N) or medium-quality (1·6% N) diets, it was calculated that buffaloes would have nitrogen balances.

scholarly journals Glucose partitioning in the pregnant ewe: Effects of undernutrition and exercise

1990 ◽  
Vol 64 (2) ◽  
pp. 449-462 ◽  
Author(s):  
B. J. Leury ◽  
A. R. Bird ◽  
K. D. Chandler ◽  
A. W. Bell
Keyword(s):  
Glucose Uptake ◽  
Energy Requirement ◽  
Live Weight ◽  
Late Pregnancy ◽  
Maternal Blood ◽  
Whole Body ◽  
Entry Rate ◽  
Glucose Transfer ◽  
Glucose Supply ◽  
Maternal Glucose

Maternal whole-body glucose entry rate and uterine and umbilical net uptakes of glucose and oxygen were measured in single-pregnant ewes which were either well-fed throughout, or fed at 0.3–0.4 predicted energy requirement for 7–21 d during late pregnancy. All ewes were studied while standing at rest and then while walking on a treadmill at 0.7 m/s on a 10° slope for 60 min. Underfed ewes suffered significant decreases in live weight and had lower fetal, but not placental, weights at 140–144 d gestation. Undernutrition also caused large decreases in maternal glycaemia and glucose entry rate, which were associated with equally large decreases in uterine and umbilical net uptakes and O2 quotients of glucose, and with a decrease in placental glucose transfer capacity. Exercise caused increases in maternal blood concentration, entry rate and uterine net uptake of glucose, the magnitudes of which were not significantly affected by plane of nutrition. Umbilical glucose uptake and placental glucose transfer capacity increased during exercise in underfed but not fed ewes. The fractional distribution of maternal glucose to the pregnant uterus, and of uterine glucose uptake to the fetus, were unaltered by undernutrition; during exercise, a disproportionately small fraction of the increased maternal glucose supply went to the uterus. The results confirm that the ovine conceptus responds to nutritional reduction in maternal glucose availability in a manner similar to non-uterine maternal tissues. Major reductions in glucose supply appear to override putative glucose-sparing mechanisms which may operate to favour the conceptus in better-nourished animals.

The effect of hexoestrol on nitrogen retention of lambs and on ration digestibility

1958 ◽  
Vol 1958 ◽  
pp. 13-17 ◽  
Author(s):  
T. R. Preston ◽  
V. Rochanasaroj ◽  
Isoline Gee
Keyword(s):  
Weight Gain ◽  
Major Part ◽  
Growth Response ◽  
Nitrogen Retention ◽  
Live Weight ◽  
Experimental Period ◽  
Feeding Period ◽  
Subcutaneous Implantation ◽  
Live Weight Gain ◽  
Series Of Experiments

It is now widely accepted that the subcutaneous implantation of stilboestrol or hexoestrol increases the rate of live-weight gain in lambs and cattle. In sheep it is generally considered that for a feeding period of up to 12 weeks a single implantation of hormone produces an adequate growth response. Perry et al.(1951), Stephens & Thompson (1952) and Bell et al.(1954) reported no advantage from repeated implantations during the experimental period. In a series of experiments at this Institute (Preston & Gee, 1957a) it has been noticed that the major part of the increased weight gain takes place during the first six weeks after hexoestrol implantation.

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