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Leucine degradation in sheep

Published online by Cambridge University Press:  09 March 2007

W. G. Bergen ,
J. R. Busboom  and
R. A. Merkel
W. G. Bergen
Affiliation:
Department of Animal Science, Growth Biology Program, Michigan State University, East Lansing, MI 48824, USA
J. R. Busboom
Affiliation:
Department of Animal Science, Growth Biology Program, Michigan State University, East Lansing, MI 48824, USA
R. A. Merkel
Affiliation:
Department of Animal Science, Growth Biology Program, Michigan State University, East Lansing, MI 48824, USA
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Abstract

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1. In vitro leucine catabolism in adipose tissue, skeletal muscle, kidney and liver homogenates was studied in sheep.

2. In Expt 1, Suffolk × Targhee ram lambs were slaughtered at 1, 28, 56, 84, 112, 140, 168, 196, 224 and 365 d of age. In Expt 2, 5-month-old crossbred wethers were fed on 80, 120 or 180 g crude protein (nitrogen × 6·25) /kg diets for 4 weeks or fed on 120 g crude protein/kg for 4 weeks and then fasted for 48 or 96 h before slaughter. Leucine catabolism was assayed in tissue homogenates for Expts 1 and 2.

3. Leucine deamination (per unit protein) was highest in skeletal muscle at day 1 and then declined; liver exhibited an activity pattern akin to muscle while kidney activity tended to rise over the duration of the study. Adipose tissue in vitro leucine deamination was higher at all ages studied and 9- to 50-fold higher than all other tissues at 365 d. Leucine decarboxylation (per unit protein) was highest at day 1 in muscle and declined to low levels (P < 0·01) after 28 d; liver and kidney decarboxylation activities were higher than muscle at all ages with kidney showing the highest activity. Whilst adipose had high initial activity it declined significantly (P < 0·01) by day 28 and remained low.

4. Dietary protein intake had no effect on leucine deamination in any tissue. Leucine decarboxylation tended to increase with protein intake for all tissues except kidney. Length of fast (96 h) resulted in a variable decline in leucine deamination; leucine decarboxylation was significantly lower in kidney, liver and adipose tissue after a 96 h fast.

5. When these in vitro enzyme activity results are related to questions concerning the role of skeletal muscle in leucine catabolism in sheep, the present findings indicate that in grown sheep, skeletal muscle has a small to moderate role in total body leucine deamination but plays a very minor role in leucine decarboxylation. Adipose tissue appears to be a major site of leucine deamination in grown sheep. These results are not in agreement with the idea that during fasting leucine becomes an important energy substrate and is oxidized in skeletal muscle as has been shown in rodents.

Type
General Nutrition Papers
Information
British Journal of Nutrition , Volume 59 , Issue 2 , March 1988 , pp. 323 - 333
Copyright
Copyright © The Nutrition Society 1988

References

Ahmed, B. M., Bergen, W. G. & Ames, N. K. (1983). Journal of Nutrition 113, 1529–1543.CrossRefGoogle Scholar
Allen, L. E., Beitz, D. C., Cramer, D. A. & Kaufman, R. G. (1976). Biology of Fat in Meat Animals, North Central Regional Research Publication no. 234. Madison, WI: University of Wisconsin.Google Scholar
Ballard, F. J., Filsell, O. H. & Jarrett, I. G. (1976). Metabolism 25, 415–418.CrossRefGoogle Scholar
Bergman, E. N., Kaufman, C. F.Wolff, J. E. & Williams, H. H. (1974). American Journal of Physiology 226, 833–837.CrossRefGoogle Scholar
Busboom, J. R. (1984). Effect of age and nutritional state on branched chain amino acid degradation in sheep. PhD Thesis, Michigan State University, East Lansing, MI, USA.Google Scholar
Chang, T. W. & Goldberg, A. L. (1978 a). Journal of Biological Chemistry 253, 3677–3684.CrossRefGoogle Scholar
Chang, T. W. & Goldberg, A. L. (1978 b). Journal of Biological Chemistry 253, 3685–3695.CrossRefGoogle Scholar
Gill, J. L. (1978). Design and Analysis of Experiments, Vol. I, pp. 183–186. Ames, Iowa: Iowa State University Press.Google Scholar
Goldberg, A. L. & Odessey, R. (1972). American Journal of Physiology 223, 1384–1391.CrossRefGoogle Scholar
Goldberg, A. L. & Tischler, M. E. (1981). In Metabolism and Clinical Implications of Branched and Keto Acids. pp. 73–78 [Walser, M. and Williams, J. R., editors]. Amsterdam: Elsevier/North Holland.Google Scholar
Goodwin, G. W., Gibboney, W., Paxton, R., Harris, R. A. & Lemons, J. A. (1987). Biochemical Journal 242, 305–308.CrossRefGoogle Scholar
Heitman, R. N. & Bergman, E. N. (1981). American Journal of Physiology 241, E465–E472.Google Scholar
Harper, A. E., Miller, R. H. & Block, K. P. (1984). Annual Review of Nutrition 4, 409–454.CrossRefGoogle Scholar
Kasperik, G. J., Dohm, G. L. & Snider, R. D. (1985). American Journal of Physiology 248, R166–R171.Google Scholar
Kaufman, R. G., St Clair, L. E. & Reger, R. J. (1963). Ovine Myology, Illinois Agricultural Experiment Station Bulletin no. 693, pp. 52–53. Urbana, IL, USA: University of Illinois.Google Scholar
Lindsay, D. B. (1982). Federation Proceedings 41, 2550–2554.Google Scholar
Lindsay, D. B. & Buttery, P. J. (1980). In Protein Deposition in Animals, pp. 125–146 [Buttery, P. J.and Lindsay, D. B., editors]. London: Butterworth.CrossRefGoogle Scholar
Lowry, O. H., Rosebrough, N. J., Farr, A. L. & Randall, R. J. (1951). Journal of Biological Chemistry 193, 265–275.CrossRefGoogle Scholar
National Research Council (1975) Nutrient Requirements of Sheep, 5th revised ed. Washington DC: National Academy of Sciences.Google Scholar
Odessey, R. & Goldberg, A. L. (1979). Biochemicial Journal 178, 475–489.CrossRefGoogle Scholar
Oh, J. H., Hume, I. D., & Torrel, D. T. (1972). Journal of Animal Science 35, 450–459.CrossRefGoogle Scholar
Owens, F. N. & Bergen, W. G. (1983). Journal of Animal Science 57, Suppl. 2, 498–518.Google Scholar
Paxton, R., Kuntz, M. & Harris, R. A. (1986). Archives of Biochemistry and Biophysics 244, 187–201.CrossRefGoogle Scholar
Pell, J. M. & Bergman, E. N. (1983). American Journal of Physiology 244, E282–E289.Google Scholar
Pell, J. M., Caldarone, E. M. & Bergman, E. N. (1983 a). Biochemical Journal 214, 1015–1018.CrossRefGoogle Scholar
Pell, J. M., Caldarone, E. M. & Bergman, E. N. (1983 b). Federation Proceedings 42, 815, Abstr.Google Scholar
Pell, J. M., Caldarone, E. M. & Bergman, E. N. (1986). Metabolism 35, 1005–1016.CrossRefGoogle ScholarPubMed
Teleni, E., Annison, E. F., Lindsay, D. B. & Mackenzie, J. (1983). Proceedings of the Nutrition Society, 42, 92A.Google Scholar
Tischler, M. E. & Goldberg, A. L. (1980). Journal of Biological Chemistry 257, 1613–1621.CrossRefGoogle Scholar
Vernon, R. G. (1980). Progress in Lipid Research 19, 23–106.CrossRefGoogle Scholar
Wagenmakers, A. J. M. & Veerkamp, J. H. (1982). Biochemical Medicine 28, 16–31.CrossRefGoogle Scholar
Walser, M. & Williamson, J. R. (1981). Metabolism and Clinical Implications of Branched Chain Amino and Keto Acids. Amsterdam: Elsevier/North Holland.Google Scholar