Hostname: page-component-586b7cd67f-2brh9 Total loading time: 0 Render date: 2024-11-29T08:45:57.623Z Has data issue: false hasContentIssue false
  • English
  • Français

The role of condensed tannins in the nutritional value of Lotus pedunculatus for sheep

*4. Sites of carbohydrate and protein digestion as influenced by dietary reactive tannin concentration

Published online by Cambridge University Press:  09 March 2007

T. N. Barry ,
T. R. Manley  and
S. J. Duncan
T. N. Barry
Affiliation:
Invermay Agricultural Research Centre, Mosgiel, New Zealand
T. R. Manley
Affiliation:
Invermay Agricultural Research Centre, Mosgiel, New Zealand
S. J. Duncan
Affiliation:
Invermay Agricultural Research Centre, Mosgiel, New Zealand
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. Vegetative secondary growth Lotus pedunculatus was cut daily, and fed fresh at hourly intervals (600 g dry matter (DM)/d) to three groups each of three sheep fitted with permanent cannulas into the rumen and duodenum. Lotus fed to two of the groups was sprayed with low and high rates of polyethylene glycol (PEG; molecular weight 3350), which specifically binds the condensed tannins (CT). Nutrient intake and faecal excretion were measured directly, duodenal flows estimated from continuous intraruminal infusion of inert ruthenium phenanthroline (Ru-P) and CrEDTA markers, and rumen pool sizes measured at slaughter.

2. Dietary concentrations of total reactive CT (i.e. that not bound to PEG) were 95, 45 and 14 g/kg DM, whilst the corresponding values for free CT were 15, 5 and 2 g/kg DM.

3. Increasing dietary reactive CT concentration linearly increased duodenal flows of non-ammonia nitrogen, but linearly decreased the apparent digestibility of energy and organic matter, and rumen digestion of hemicellulose but not of cellulose. Rumen digestion as a proportion of total digestion was increased by the higher PEG rate for organic matter, energy, pectin and lignin.

4. High dietary CT concentration was associated with increased N retention. Rumen ammonia concentration and pool size showed only a slight decline on this diet, indicating that there must have been increased recycling of N into the rumen.

5. Increasing dietary reactive CT concentration had no effect on the rate at which carbohydrate constituents were degraded in the rumen per unit time (FDR), but increased the rate at which their undegraded residues (FOR) left the rumen per unit time. The latter appeared to be the principal mechanism by which rumen digestion as a proportion of total digestion was reduced at high dietary CT concentrations. From a comparison of FDR and FOR of carbohydrate components in lotus and Brassica oleracea diets, it was concluded that hemicellulose digestion was rate-limiting for rumen cell-wall digestion, probably due to bonding with lignin. However, the considerable post-rumen digestion of hemicellulose was not associated with post-rumen lignin digestion.

6. It was concluded that a desired concentration of CT in Lotus sp. should represent a balance between the positive effect of CT in improving the efficiency of N digestion and their negative effect in depressing rumen carbohydrate digestion. A recommended concentration is 3WOg/kg DM.

Type
Papers on General Nutrition
Information
British Journal of Nutrition , Volume 55 , Issue 1 , January 1986 , pp. 123 - 137
Copyright
Copyright © The Nutrition Society 1986

References

REFERENCES

Barry, T. N. (1981). British Journal of Nutrition 46, 521–532.Google Scholar
Barry, T. N. (1982). Proceedings of the Nutrition Society of New Zealand 7, 66–76.Google Scholar
Barry, T. N. & Duncan, S. J. (1984). British Journal of Nutrition 51, 485–491.CrossRefGoogle Scholar
Barry, T. N. & Forss, D. A. (1983). Journal of the Science of Food and Agriculture 34, 1047–1056.CrossRefGoogle Scholar
Barry, T. N. & Manley, T. R. (1984). British Journal of Nutrition 51, 493–504.CrossRefGoogle Scholar
Barry, T. N. & Manley, T. R. (1985). British Journal of Nutrition 54, 753–761.Google Scholar
Barry, T. N., Manley, T. R. & Duncan, S. J. (1984). Journal of Agricultural Science, Cambridge 102, 479–486.CrossRefGoogle Scholar
Barry, T. N. & Reid, C. S. W. (1986). In Forage Legumes for Energy Efficient Animal Production [Barnes, R. F., Minson, D. J. and Brougham, R. W., editors] (In the Press).Google Scholar
Beaver, D. E. & Siddons, R. C. (1986). In Control of Digestion and Metabolism in the Ruminant [Milligan, L. P. and Grovum, W. L., editors] (In the Press).Google Scholar
Binnerts, W. T., van't Klooster, A. Th. & Frens, A. M. (1968). Veterinary Record 82, 470.Google Scholar
Corbett, J. L. & Pickering, F. S. (1983). In Feed Information and Animal Production, pp. 301–302 [Robarts, G. E. and Packham, R. G., editors]. Slough, UK: Commonwealth Agricultural Bureaux.Google Scholar
Egan, A. R. & Ulyatt, M. J. (1980). Journal of Agricultural Science, Cambridge 94, 47–56.Google Scholar
Faichney, G. J. (1975). In Digestion and Metabolism in the Ruminant, pp. 275–291 [McDonald, I. W. and Warner, A. C. I., editors]. Armidale, Australia: University of New England Press.Google Scholar
Harkin, J. M. (1973). In Chemistry and Biochemistry of Herbage, pp. 323–374 [Butler, G. W. and Bailey, R. W., editors]. London and New York: Academic Press.Google Scholar
John, A. & Lancashire, J. A. (1981). Proceedings of the New Zealand Grassland Association 42, 152–159.CrossRefGoogle Scholar
MacRae, J. C. & Ulyatt, M. J. (1974). Journal of Agricultural Science, Cambridge 82, 309–319.CrossRefGoogle Scholar
Tan, T. N., Weston, R. H. & Hogan, J. P. (1971). International Journal of Applied Radiation and Isotopes 22, 301–308.CrossRefGoogle Scholar
Wong, E. (1973). In Chemistry and Biochemistry of Herbage, pp. 265–322 [Butler, G. W. and Bailey, R. W., editors]. London and New York: Academic Press.Google Scholar