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Dynamic aspects of ammonia and urea metabolism in sheep

Published online by Cambridge University Press:  24 July 2007

J. V. Nolan  and
R. A. Leng
J. V. Nolan
Affiliation:
Department of Biochemistry and Nutrition, The University of New England, Armidale, NS W, 2351, Australia
R. A. Leng
Affiliation:
Department of Biochemistry and Nutrition, The University of New England, Armidale, NS W, 2351, Australia
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Abstract

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1. To obtain a quantitative model for nitrogen pathways in sheep, a study of ammonia and urea metabolism was made by using isotope dilution techniques with [15N]ammonium sulphate and [15N]urea and [14C]urea.

2. Single injection and continuous infusion techniques of isotope dilution were used for measuring ammonia and urea entry rates.

3. Sheep were given 33 g of chaffed lucerne hay every hour; the mean dietary N intake was 23.4 g/d.

4. It was estimated that 59% of the dietary N was digested in the reticulo-rumen; 29% of the digested N was utilized as amino acids by the micro-organisms, and 71% was degraded to ammonia.

5. Of the 14.2 g N/d entering the ruminal ammonia pool, 9.9 g N/d left and did not return to the pool, the difference of 4.3 g N/d represented recycling, largely within the rumen itself (through the pathways: ruminal ammonia → microbial protein → amino acids → ammonia).

6. Urea was synthesized in the body at a rate of 18.4 g N/d from 2.0 g N/d of ammonia absorbed through the rumen wall and 16.4 g N/d apparently arising from deamination of amino acids and ammonia absorbed from the lower digestive tract.

7. In the 24 h after intraruminal injection of [15N]ammonium salt, 40–50% of the N entering the plasma urea pool arose from ruminal ammonia; 26% of the 15N injected was excreted in urinary N.

8. Although 5.1g N/d as urea was degraded apparently in the digestive tract, only 1.2g N/d appeared in ruminal ammonia; it is suggested that the remainder may have been degraded in the lower digestive tract.

9. A large proportion of the urea N entering the digestive tract is apparently degraded and absorbed and the ammonia incorporated in the pools of nitrogenous compounds that turn over only slowly. This may be a mechanism for the continuous supply to the liver of ammonia for these syntheses.

10. There was incorporation of 15N into bacterial fractions isolated from rumen contents after intraruminal and intravenous administration of [15N]ammonium salts and [15N]urea respectively.

11. A model for N pathways in sheep is proposed and, for this diet, many of the pool sizes and turn-over rates have been either deduced or estimated directly.

Type
General Nutrition
Information
British Journal of Nutrition , Volume 27 , Issue 1 , January 1972 , pp. 177 - 194
Copyright
Copyright © The Nutrition Society 1972

References

Abe, M. & Kandatsu, M. (1969). Jap. J. zootech. Sci. 40, 313.Google Scholar
Adams, J. C., Gazaway, J. A. Jr., Brailsford, M. D., Hartman, P. A. & Jacobson, N. L. (1966). Experientia 22, 717.CrossRefGoogle Scholar
Baker, N. & Rostarni, H. (1969). J. Lipid Res. 10, 83.CrossRefGoogle Scholar
Baker, N., Shipley, R. A., Clark, R. E. & Incefy, G. E. (1959). Am. J. Physiol. 196, 245.CrossRefGoogle Scholar
Bloomfield, R. A. (1961). Diss. Abstr. 21, 2455.Google Scholar
Bremner, J. M. (1965). In Methds of Soil AnaZysis [Black, C. A., Evans, D. D, White, J. L., Ensminger, L. E. and Clark, F. E., editors]. Agronomy 9, 1149.Google Scholar
Coleman, G. S. (1967). J. gen. Microbiol. 47, 449.CrossRefGoogle Scholar
Cook, K.&, Brown, R. E. & Davis, C. L. (1965). J. Dairy Sci. 48, 475.CrossRefGoogle Scholar
Demaux, C., Le Bars, H., Mollé, J., Rérat, A. & Simonnet, H. (1961). Bull. Acad. vét. Fr. 34, 85.CrossRefGoogle Scholar
Egan, A. R. (1965). Aust. J. agric. Res. 16, 463.CrossRefGoogle Scholar
Egan, A. R. & Moir, R. (1965). Aust. J. agric. Res. 16, 437.CrossRefGoogle Scholar
el-Shazly, K. (1952). Biochem. J. 51, 640.CrossRefGoogle Scholar
Farlin, S. D., Brown, R. E. & Garrigus, U. S. (1968). J. Anim. Sci. 27, 771.CrossRefGoogle Scholar
Fürst, P., Jonsson, A., Josephson, B. & Vinnars, E. (1970). J. appl. Physiol. 29, 307.CrossRefGoogle Scholar
Hecker, J. F. & Nolan, J. V. (1971). Aust. J. biol. Sci. 24, 403.CrossRefGoogle Scholar
Hogan, J. I.. (1964). Aust. J. agric. Res. 15, 397.CrossRefGoogle Scholar
Hoogenraad, N. J., Hird, F. J. R., I-Iolmes, I. & Millis, N. F. (1967). J. gen. Virol. 1, 575.CrossRefGoogle Scholar
Houpt, T. R. (1970). In Physiology of Digestion andMetabolism in the Ruminant p.119 [Phillipson, A. T editor] Newcastle upon Tyne: Oriel Press.Google Scholar
Houpt, T. R. & Houpt, K. A. (1969). Am. J. Physiol. 214, 1296.CrossRefGoogle Scholar
Hungate, R. E. (1966). The Rumen and its Microbes. New York: Academic Press Inc.Google Scholar
Hungate, R. E. (1967). In Handbook of Physiology Vol. 5, Ch. 130, p. 2725 [Code, C. F. and W, Heidel editors.] Baltimore: Williams & Wilkins Co.Google Scholar
Juh´sz, B. (1965). Acta. vet. Acad. Sci. hung. 15, 25.Google Scholar
Lewis, D. (1955). Br. J. Nutr. 9, 215.CrossRefGoogle Scholar
Loosli, J. K., Williams, H. H., Thomas, W. E., Ferris, F. H. & Maynard, L. A. (1949). Science., N. Y. 110, 144.CrossRefGoogle Scholar
McDonald, I. W. (1962). Proc. N.Z. Sac. Anim. Prod. 22, 79.Google Scholar
McDonald, I. W. (1968). Aust. vet. J. 4, 145.CrossRefGoogle Scholar
Martin, A. E. & Ross, P. J. (1968). 9th Int. Congress of Soil Science Transactions, Adelaide, Australia, 3, 521.Google Scholar
Mason, V. C. (1969). J. ugric. Sci., Camb. 73, 99.CrossRefGoogle Scholar
Nelder, J. A. & Mead, R. (1965). Computer J. 7, 308.CrossRefGoogle Scholar
Phillipson, A. T., Dobson, M. J., Blackburn, T. H. & Brown, M. (1962). Br. J. Nutr. 16, 151.CrossRefGoogle Scholar
Pilgrim, A. F., Gray, F. V. & Belling, C. B. (1969). Br. J. Nutr. 23, 647.CrossRefGoogle Scholar
Pilgrim, A. F., Gray, F. V., Weller, R. A. & Belling, C. B. (1970).Br. J. Nutr. 24, 589.CrossRefGoogle Scholar
Portugal, A. V. (1963). Some aspects of protein and amino acid metabolism in the mmen of sheep. PhD Thesis University of Aberdeen.Google Scholar
Portugal, A. V. & Sutherland, T. M. (1966). Nature, Lond. 209, 510.CrossRefGoogle Scholar
Rescigno, A. & Segre, G. (1966). Drug and Tracer Kinetics. Waltham: Blaisdell.Google Scholar
Smith, R. H. (1969). J. Dairy Res. 36, 313.CrossRefGoogle Scholar
Somers, M. (1961). Aust. J. exp. Biol. 39, 111.CrossRefGoogle Scholar
Thornton, R. F., Bird, P. K., Somers, M. & Moir, R. J. (1970). Aust. J. agric. Res. 21, 345.CrossRefGoogle Scholar
Virtanen, A. I. (1966). Science, N. Y. 153, 1603.CrossRefGoogle Scholar
von Engelhardt, W. & Nickel, W. (1965). Pflügers Arch. ges. Physiol. 286, 57.CrossRefGoogle Scholar
Waldo, D. R. (1968). J. Dairy Sci. 51, 265.CrossRefGoogle Scholar
Warner, A. C. I. (1956). J. gen. Microbiol. 14, 749.CrossRefGoogle Scholar
Weston, R. H. & Hogan, J. P. (1967). Aust. J. biol. Sci. 20, 967.CrossRefGoogle Scholar
White, R. G., Steel, J. W., Leng, R. A. & Luick, J. R. (1969). Biochem. J. 114, 203.CrossRefGoogle Scholar
Wright, D. E. & Hungate, R. E. (1967). Appl. Microbiol. 15, 152.CrossRefGoogle Scholar