Nitrogen Requirements and Urea Recycling in an Omnivorous Marsupial, the Northern Brown Bandicoot Isoodon macrourus

2005 ◽  
Vol 78 (3) ◽  
pp. 456-467 ◽  
Author(s):  
Vanessa Young ◽  
Ian D. Hume
Keyword(s):  
1982 ◽  
Vol 62 (4) ◽  
pp. 1193-1197 ◽  
Author(s):  
P. A. THACKER ◽  
J. P. BOWLAND ◽  
L. P. MILLIGAN ◽  
E. WELTZIEN

The kinetics of urea recycling were determined in six female crossbred pigs utilizing a radioisotope dilution technique. The experimental animals were fed three times daily 500 g of a corn-soybean meal diet formulated to contain 8.4, 15.8 or 24.7% crude protein. Nitrogen digestibility, urinary nitrogen excretion, total nitrogen excretion and retained nitrogen were highest on the 24.7% protein diet and decreased with decreasing dietary protein. Urea pool size, entry rate and excretion rate were also highest on the 24.7% protein diet and decreased with decreasing protein intake. Expressed as a percentage of the total entry rate, a significantly higher percentage of urea was recycled in pigs fed the low protein diets compared with those fed a higher protein diet. Key words: Pig, urea, recycling, kinetics, protein


2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 176-176
Author(s):  
Daniel Columbus ◽  
Jack Krone ◽  
Miriam ter borgh ◽  
Kasia Burakowska ◽  
Gillian Gratton ◽  
...  

Abstract Previous studies have indicated that pigs are capable of nitrogen salvage via urea recycling, which involves the movement of urea into the gastrointestinal tract and incorporation of nitrogen into endogenous or microbially produced amino acids. Aquaporins (AQP) and urea transporter B (UT-B) have been shown to contribute to urea transport in ruminants; however, it is unclear whether the same processes contribute to urea movement in the intestinal tract of the pig. The objective of this study was to characterize the presence and relative contribution of known urea transporters to urea flux in the growing pig. A total of 9 barrows of 50.8±0.9 kg BW were euthanized and samples of intestinal tissue were obtained from the duodenum, jejunum, ileum, cecum, and colon. All tissue samples were analyzed for mRNA abundance of UT-B and AQP-3, 7, and 10 via qPCR. Immediately after tissue collection, samples from jejunum and cecum were placed in Ussing chambers for analysis of serosal-to-mucosal urea flux using 14C-urea (49.95 kBq). Serosal-to-mucosal urea flux was measured across intestinal tissue samples with no inhibition or with addition of phloretin (1 mM) to inhibit UT-B-mediated transport, NiCl2 (1 mM) to inhibit AQP-mediated transport, or both inhibitors. UT-B was most highly expressed in the cecum (P < 0.05), while AQP-3, 7, and 10 were most highly expressed in the jejunum (P < 0.05). Serosal-to-mucosal urea flux occurred in both the jejunum and the cecum and was higher in the cecum (42.7 vs. 67.8±5.01 µmol/cm2/h; P < 0.05), confirming the capacity for urea recycling into the gut in pigs; however, neither flux rate was influenced by urea transporter inhibitors (P > 0.05). The results of this study indicate that while known urea transporters are present in the gastrointestinal tract of pigs, they do not play a significant role in urea transport.


1965 ◽  
Vol 24 (2) ◽  
pp. 341-346 ◽  
Author(s):  
L. V. Packett ◽  
T. D. D. Groves
Keyword(s):  

1988 ◽  
Vol 116 (1) ◽  
pp. 71-79 ◽  
Author(s):  
I. K. Martin ◽  
I. R. McDonald

ABSTRACT In undisturbed pademelon wallabies (Thylogale billardierii) with indwelling jugular venous catheters, an increase in the plasma cortisol concentration from 0.25±0.05 to 1.35±0.15 (s.e.m.) μmol/l in 2 h, during i.v. infusion of cortisol at 1.0 mg/kg per h, caused no significant change in the plasma glucose concentration from the control value of 4.26±0.25 mmol/l. The rates of appearance (Ra) and metabolic clearance (MCR) of glucose, measured by steady-state isotope dilution, also did not change significantly from the control values of 14.9±0.7 μmol/kg per min and 3.52±0.19 ml/kg per min respectively. Twice-daily i.m. injections of 7 mg cortisol/kg for 7 days caused increases in plasma concentrations of cortisol, from 0.26±0.02 to 0.66±0.04 μmol/l on day 7, and glucose, from 5.1±0.1 to 7.2±0.6 mmol/l by day 5. The concentration of glycogen in the liver of wallabies fasted for 24 h increased from the control level of 1.17±0.56 to 5.92±1.14 g/100 g on day 7 (P<0.01), but mean glucose Ra and MCR did not change significantly. Plasma concentrations of α-amino nitrogen rose from 2.73±0.13 to 3.22±0.12 mmol/l on day 1 and remained at this level. Plasma concentrations of urea rose from 8.59±0.62 to 9.70±0.32 mmol/l on day 1, but then declined below the control level. Food intake and urinary excretion of nitrogen did not change in undisturbed animals. However, fasting followed by liver biopsy was accompanied by urinary excretion of nitrogen in excess of food intake, persisting until day 2 of treatment. The transient effect of cortisol on the plasma concentration of urea and lack of effect on urinary excretion of nitrogen could be explained by urea recycling, as indicated by a low urinary urea nitrogen: total nitrogen ratio and failure to excrete more than a mean of 26% of infused urea. It is concluded that cortisol has no short-term effect on carbohydrate metabolism in this marsupial. In the long term it can increase hepatic carbohydrate reserves through utilization of tissue amino nitrogen, the resulting urea being conserved by recycling. J. Endocr. (1988) 116, 71–79


1980 ◽  
Vol 67 (1) ◽  
pp. 215-218 ◽  
Author(s):  
Nissim Silanikove ◽  
Haim Tagari ◽  
Amiram Shkolnik
Keyword(s):  

Author(s):  
E.A. Bailey ◽  
D.W. Brake ◽  
David E. Anderson ◽  
M.L. Jones ◽  
Evan C. Titgemeyer ◽  
...  
Keyword(s):  

1974 ◽  
Vol 38 (3) ◽  
pp. 565-571 ◽  
Author(s):  
Ronald L. Prior ◽  
Harold F. Hintz ◽  
John E. Lowe ◽  
Willard J. Visek
Keyword(s):  

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