Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-19T06:42:36.774Z Has data issue: false hasContentIssue false
  • English
  • Français

Protein utilization in the young steer: digestion and nitrogen retention of 15N-labelled rumen bacterial protein

Published online by Cambridge University Press:  09 March 2007

D. N. Salter  and
R. H. Smith
D. N. Salter
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, Berks RG2 9AT
R. H. Smith
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading, Berks RG2 9AT
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

1. 15N-labelled mixed rumen bacteria, obtained from a steer that had received [15N]urea in its diet, were disrupted ultrasonically and freed from nucleic acids and their degradation products. Samples were subjected to a simulated abomasal digestion with pepsin.

2. The digests were infused with a non-absorbable marker (polyethylene glycol) into the duodenum of four steers equipped with simple duodenal and re-entrant ileal cannulas and adapted to a diet of barley straw, flaked maize and urea. The outflow from the ileum was collected for 6–7 h. The mean value for the digestibility of 15N bacterial proteins in the small intestine was estimated to be 0.74.

3. [14C]urea was administered intravenously during the infusion of the 15N-labelled protein into the duodenum. Urine and faeces were collected for the next 48 h and the proportion of urea-N produced, that was excreted in the urine, estimated from urine 14C excretion. Total urea 15N production was estimated from this value and the amount of 15N excreted in the urine. The mean proportion of 15N absorbed that was deposited in body protein, 0.70, was calculated by difference. The over-all efficiency of utilization of 15N in the infused rumen bacterial protein was 0.52.

4. An approximate estimate of the mean rate of protein synthesis calculated from the data was 24 g/kg body-weight (W)0.75 per d and compared with an estimated net deposition of protein of 1.67 g/kg W0.75 per d.

5. The importance of these values in factorial schemes for estimating ruminant N requirements is discussed.

Type
Papers on General Nutrition
Information
British Journal of Nutrition , Volume 51 , Issue 3 , May 1984 , pp. 531 - 539
Copyright
Copyright © The Nutrition Society 1984

References

REFERENCES

Agricultural Research Council (1980). The Nutrient Requirements of Ruminant Livestock: Technical Review by an Agricultural Research Council Working Party. Slough: Commonwealth Agricultural Bureaux.Google Scholar
Armstrong, D. G. & Hutton, K. (1975). In Digestion and Metabolism in the Ruminant pp. 432–447 [McDonald, W.I., Warner, A. C. I., editors]. University of New England Publishing Unit: Armidale, Australia.Google Scholar
Blake, J. S., Salter, D. N. & Smith, R. H. (1983). British Journal of Nutrition 50, 769–782.CrossRefGoogle Scholar
Cocimano, M. R. & Leng, R. A. (1967). British Journal of Nutrition 21, 353–371.CrossRefGoogle Scholar
Goulden, J. D. S. & Salter, D. N. (1979). Analyst 104, 756–765.CrossRefGoogle Scholar
Harmeyer, J. & Martens, H. (1980). Journal of Dairy Science 63, 1707–1728.CrossRefGoogle Scholar
Lobley, G. E., Milne, V., Lovie, J. M., Reeds, P. J. & Pennie, K. (1980). British Journal of Nutrition 43, 491–502.CrossRefGoogle Scholar
Nolan, J. V., Norton, B. W. & Leng, R. A. (1976). British Journal of Nutrition 35, 127–147.CrossRefGoogle Scholar
Salter, D. N., Daneshvar, K. & Smith, R. H. (1979). British Journal of Nutrition 41, 197–209.CrossRefGoogle Scholar
Salter, D. N. & Smith, R. H. (1977). British Journal of Nutrition 38, 207–216.CrossRefGoogle Scholar
Salter, D. N., Smith, R. H. & Hewitt, D. (1983). British Journal of Nutrition 50, 427–435.CrossRefGoogle Scholar
Smith, R. H. (1975). In Digestion and Metabolism in the Ruminant pp. 399–415 [McDonald, W.I., Warner, A. C. I., editors]. University of New England Publishing Unit: Armidale, Australia.Google Scholar
Smith, R. H. & McAllan, A. B. (1971). British Journal of Nutrition 25, 181–190.CrossRefGoogle Scholar
Smith, R. H. & McAllan, A. B. (1974). British Journal of Nutrition 31, 27–34.CrossRefGoogle Scholar
Storm, E. & Ørskov, E. R. (1982). Proceedings of the Nutrition Society 41, 78A.Google Scholar
Tas, M. V., Evans, R. A. & Axford, R. J. E. (1981). British Journal of Nutrition 45, 167–174.CrossRefGoogle Scholar
Waterlow, J. C., Garlick, P. J. & Millward, D. J. (1978 a). Protein Turnover in Mammalian Tissues and in the Whole Body. North Holland Publishing Co.: Oxford.Google Scholar
Waterlow, J. C., Golden, M. H. N. & Garlick, P. J. (1978 b). American Journal of Physiology 235, E165–E174.Google Scholar