Hostname: page-component-cd9895bd7-8ctnn Total loading time: 0 Render date: 2024-12-25T01:01:55.832Z Has data issue: false hasContentIssue false

The efficiency of microbial protein synthesis in the rumen and the degradability of feed nitrogen between the mouth and abomasum in steers given different diets

Published online by Cambridge University Press:  09 March 2007

A. B. McAllan
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading RG2 9AT, Berkshire
R. H. Smith
Affiliation:
National Institute for Research in Dairying, Shinfield, Reading RG2 9AT, Berkshire
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. Protozoa-free steers with simple rumen and abomasal cannulas were given basal diets consisting of a concentrate mixture of flaked maize and tapioca with barley straw (BS) or alkali-treated barley straw (BSA). Other diets were supplemented with urea (BSU and BSAU respectively) or with fish meal replacing the tapioca (BSF and BSAF respectively). The diets were isoenergetic and calculated to provide sufficient metabolizable energy (ME) to support a growth rate of 0.5 kg/d. Rumen-degradable nitrogen (RDN): ME values (g/MJ) were estimated to be 0.50, 1.20 and 0.80 for the basal diet, urea- and fish-meal-supplemented diets respectively. RNA and α, ε-diaminopimelic acid (DAP) were used as microbial markers. 103Ruthenium and polyethylene glycol (PEG) were given as flow markers and flows (g/24 h) at the abomasum of organic matter (OM) and nitrogenous constituents were calculated.

2. Samples of mixed bacteria separated from rumen digesta from animals receiving N-supplemented diets contained significantly more N than those from animals receiving basal diets (approximately 74 and 62 mg/g dry matter (DM) respectively) but there were no other significant differences in total-N contents between treatments. RNA-N: total-N values were similar for all diets (approximately 0.13). DAP-N: total-N values were significantly lower in bacteria from animals receiving alkali-treated (AT) rather than untreated (UT) straw (approximately 0.008 and 0.011 respectively).

3. The proportion of OM intake digested in the rumen (ADOM) was significantly higher for animals receiving AT straw rather than UT straw (approximately 0.54 and 0.43 respectively). N supplementation had no effect on OM digestibility.

4. When basal rather than N-supplemented diets or AT-straw- rather than UT-straw-containing diets were given, there were significantly lower flows of ammonia-N, non-ammonia-N (NAN) and microbial-N (based on RNA flow, MN(RNA)) at the abomasum. Mean daily MN(RNA) flows (g) were 21, 30, 31, 16, 27 and 28 for diets BS, BSU, BSF, BSA, BSAU and BSAF respectively. These correspond to estimated efficiencies of microbial protein synthesis, expressed as g MN(RNA) /kg truly-digested OM, at 14, 22, 22, 12, 18 and 19 respectively. Values were significantly lower for basal as compared with corresponding N-supplemented diets and for AT-straw diets as compared with corresponding UT-straw diets.

5. Estimated mean proportions of total feed-N intake degraded in the rumen, based on MN(RNA) as microbial marker, of diets BS, BSU and BSF were 0.60, 0.74 and 0.47 respectively; corresponding values for diets BSA, BSAU and BSAF were 0.72, 0.73 and 0.36 respectively. Making certain assumptions, the mean proportions of fish-meal-N digested in the rumen were calculated to be 0.23 and 0.14 respectively for UT- and AT-straw diets. The values were not significantly different. Values for microbial flows based on DAP as marker were significantly lower, by about 25%, than those based on RNA.

Type
Papers on General Nutrition
Copyright
Copyright © The Nutrition Society 1984

References

Agricultural Research Council (1980). The Nutrient Requirements of Ruminant Livestock. Slough: Commonwealth Agricultural Bureaux.Google Scholar
Berger, L. L., Klopfenstein, T. J. & Britton, R. A. (1980). Journal of Animal Science 50, 745749.CrossRefGoogle Scholar
Cochran, W. G. & Cox, G. M. (1962). Experimental Designs, 2nd ed., p. 50. New York: J. Wiley & Sons Inc.Google Scholar
Durand, M. & Kawashima, R. (1980). In Digestive Physiology and Metabolism in Ruminants, p. 375 [Ruckebusch, Y. and Thivend, P., editors]. Lancaster: MTP Press Ltd.CrossRefGoogle Scholar
Elliott, R. & Armstrong, D. G. (1982). Journal of Agricultural Science, Cambridge 99, 5160.CrossRefGoogle Scholar
Hogan, J. P. & Weston, R. H. (1971). Australian Journal of Agricultural Research 22, 951962.Google Scholar
Jones, G. A., MacLeod, R. A. & Blackwood, A. C. (1964). Canadian Journal of Microbiology 10, 379387.CrossRefGoogle Scholar
Latham, M. J. (1980). In Microbial Adhesion to Surfaces, p. 339 [R., C. W., Berkeley, J. M., Lynch, J., Melling, P. R. and Rutter Vincent, B., editors]. Chichester: Ellis Horwood.Google Scholar
Latham, M. J., Hobbs, D. G. & Harris, P. J. (1979). Annales de Recherche Veterinaires 10, 244245.Google Scholar
McAllan, A. B. & Smith, R. H. (1969). British Journal of Nutrition 23, 671681.CrossRefGoogle Scholar
McAllan, A. B. & Smith, R. H. (1977). British Journal of Nutrition 37, 5565.CrossRefGoogle Scholar
McAllan, A. B. & Smith, R. H. (1983 a). British Journal of Nutrition 49, 119127.CrossRefGoogle Scholar
McAllan, A. B. & Smith, R. H. (1983 b). British Journal of Nutrition 50, 445454.CrossRefGoogle Scholar
Merry, R. J. & McAllan, A. B. (1983). Proceedings of the Nutrition Society 42, 49A.Google Scholar
Ministry of Agriculture, Fisheries and Food (1975). Technical Bulletin no. 33. London: H.M. Stationery Office.Google Scholar
Ololade, B. G. & Mowat, D. N. (1975). Journal of Animal Science 40, 351357.CrossRefGoogle Scholar
Redman, R. G., Kellaway, R. C. & Leibholz, J. (1980). Proceedings of the Australian Society of Animal Production 13, 482.Google Scholar
Siddons, R. C., Beever, D. E. & Nolan, J. V. (1982). British Journal of Nutrition 48, 377389.CrossRefGoogle Scholar
Smith, R. H. & McAllan, A. B. (1970). British Journal of Nutrition 24, 545556.CrossRefGoogle Scholar
Smith, R. H. & McAllan, A. B. (1974). British Journal of Nutrition 31, 2734.CrossRefGoogle Scholar
Smith, R. H., McAllan, A. B., Hewitt, D. & Lewis, P. E. (1978). Journal of Agricultural Science, Cambridge 90, 557568.CrossRefGoogle Scholar
Smith, R. H., Salter, D. N., Sutton, J. D. & McAllan, A. B. (1975). Tracer Studies on Non-protein Nitrogen for Ruminants, Vol. 2, pp. 8193. Vienna: International Atomic Energy Authority.Google Scholar
Stewart, C. S., Dinsdale, D., Cheng, K.-J. & Paniagua, C. (1979). In Straw Decay and its Effect on Disposal and Utilisation, pp. 123130 [Grossbard, E. G., editors]. Chichester: J. Wiley.Google Scholar
Van Eenaeme, C., Lambot, O., Bienfait, J. M., Nicks, B. & Van Nevel, C. J. (1979). Annales de Recherche Veterinaires 10, 323325.Google Scholar
Work, E. & Dewey, D. L. (1953). Journal of General Microbiology 9, 394399.CrossRefGoogle Scholar