Abstract
The effects of drying temperature on chemical composition and nutritive value of leaves of the shrub legumes Acacia angustissima (Miller) Kuntze, Calliandra calothyrsus Meissn and Leucaena leucocephala (Lam.) de Wit were determined in two studies in Zimbabwe. In the first study, the effects of shade-, sun- and oven-drying leaves on chemical composition and protein precipitation capacity of tannin extracts were studied. Drying method affected (P<0.01) chemical composition, with cell wall polysaccharides increasing from shade drying to oven drying. Calliandra calothyrsus leaves had the highest total phenolics, tannin phenolics and the lowest N content. About 40% of phenolics in L. leucocephala were non-tannin compared to less than 15% in A. angustissima and C. calothyrsus. Extractable proanthocyanidins and their capacity to precipitate protein were affected (P<0.01) by drying method; extracts from shade-dried leaves were 10% and 20% more reactive than extracts from sun- and oven-dried leaves, respectively. The relative degree of polymerisation of the proanthocyanidins was higher (P<0.01) for oven-dried (1.44) leaves compared to shade-dried (1.01) and sun-dried (1.00) leaves. Drying temperature influences the nutrient–polyphenolic interactions in A. angustissima, C. calothyrsus and L. leucocephala leaves and these interactions have important implications for feed evaluation protocols and for use of these leaves in ruminant feeding systems. The second study considered the effects of feeding sun-dried or fresh leaves of the three shrub legumes as supplements to native pasture hay on nutrient intake and digestion by goats. Feeding the fresh or dry leaves made no difference in terms of dry matter intake and digestion, and N digestion. This offers farmers flexibility in terms of feeding strategies, as they can feed the browse in any form that suits their farm situation. Increasing the level of C. calothyrsus in the diet increased faecal N. Nitrogen retention was lower for animals fed with C. calothyrsus compared to those fed with the other browses.
This is a preview of subscription content, access via your institution.
References
Ahn J.H., Elliot R. and Norton B.W. 1997. Oven drying improves the nutritional value of Calliandra calothyrsus and Gliricidia sepium as supplements for sheep given low-quality straw. Journal of the Science of Food and Agriculture 75: 503–510.
AOAC (Association of Official Analytical Chemists) 1990. Official Methods of Analysis. 13th edition, AOAC, Washington DC, USA. 1018 pp.
Butler, L.G., 1982. Relative degree of polymerization of sorghum tannin during seed development and maturation. Journal of Agricultural and Food Chemistry 30: 1090–1094.
Gutteridge H.M. and Shelton R.C. 1994. The role of forage tree legumes in cropping and grazing systems. In: Gutteridge H.M. and Shelton R.C. (eds), Forage Tree Legumes in Tropical Agriculture. CAB International, UK, pp. 3–11.
Hagerman A. 1987. Radial diffusion method for determining tannin in plant extracts. Journal of Chemical Ecology 13: 437–449.
Hagerman A.E. 1992. Tannin-protein interactions. In: Ho C., Lee C.Y. and Huang M. (eds), Phenolic Compounds in Food and Their Effects on Health: 1. Analysis, Occurrence and Chemistry. American Chemical Society Symposium Series 506, Washington DC, USA.
Hove L. 1999. Proanthocyanidins and their influence on the nutritive value of leaves from the shrub legumes Acacia angustissima (Miller) Kuntze, Calliandra calothyrus Meissn and Leucaena leucocephala (Lam.) de Wit fed as supplements in diets for ruminants. DPhil Thesis (unpublished), University of Zimbabwe, Harare, Zimbabwe.
Jackson F.S., Barry T.N., Lascano, C. and Palmer B. 1996. The extractable and bound condensed tannin content of leaves from tropical tree, shrub and forage legumes. Journal of the Science of Food and Agriculture 71: 103–110.
Mahyuddin P., Little D.A. and Lowry J.B., 1988. Drying treatment drastically affects feed evaluation and feed quality with certain tropical forage species. Animal Feed Science and Technology 22: 69–78.
Makkar H.P.S. 1995. Quantification of tannins: A laboratory manual in pasture forage and livestock program. International Centre for Agricultural Research in the Dry Areas, Allepo, Syria.
Makkar H.P.S. and Singh B. 1991. Effects of drying conditions on tannin, fibre and lignin levels in mature oak (Quercus incana) leaves. Journal of the Science of Food and Agriculture 54: 323–328.
Mangan J.L. 1988. Nutritional effects of tannins in animal feeds. Nutrition Research Reviews 1: 209–231.
Martin J.S and Martin M.M. 1982. Tannin assays in ecological studies: lack of correlation between phenolics, proanthocyanidins and protein precipitating constituents in mature foliage of six oak species. Oecologia 54: 205–211.
McLeod M.N. 1974. Plant tannins-their role in forage quality. Nutrition Abstracts and Reviews 44: 803–815.
Michalet-Doreau B. and Ould-Bah M.Y.B. 1992. Influence of hay making on in situ nitrogen degradability of forages in cows. Journal of Dairy Science 75: 792–788.
Miller P.R. and Ehlke N.J. 1994. Condensed tannin relationships with in vitro forage quality analyses for birdsfoot trefoil. Crop Science 34: 1074–1079.
Norton B.W. and Ahn J.H. 1997. A comparison of fresh and dried Calliandra calothyrsus supplements for sheep given a basal diet of barley straw. Journal of Agricultural Science, Cambridge 129: 485–494.
Palmer B. and Schlink A.C. 1992. The effect of drying on the intake and rate of digestion of the shrub legume Calliandra calothyrsus. Tropical Grasslands 26: 89–93.
Reed J.D., Horvath P.J., Allen M.S. and van Soest P.J. 1985. Gravimetric determination of soluble phenolics including tannins from leaves by precipitation with trivalent ytterbium. Journal of the Science of Food and Agriculture 36: 255–261.
Terril T.H., Windham W.R., Hoveland C.S. and Amos H.E. 1989. Forage preservation method influences on tannin concentration, intake, and digestibility of Sericea lespedeza by sheep. Agronomy Journal 81: 435–439.
Terril T.H., Rowan A.M., Douglas G.B. and Barry T.N. 1992. Determination of extractable and bound condensed tannin con-centrations in forages and plants, protein concentrate meals and cereal grains. Journal of the Science of Food and Agriculture 58: 321–329.
Tilley J.M and Terry R.A. 1963. A two-stage technique for in vitro digestion of forage crops. Journal of the British Grasslands Society 18: 104–111.
Van Soest 1994. Nutritional Ecology of the Ruminant. 2nd Edition, Cornell University Press, Ithaca, USA.
Van Soest P.J. and Robertson J.B. 1985. Analysis of Forages and Fibrous Foods. A Laboratory Manual 613. Cornell University, NY, USA.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Hove, L., Ndlovu, L. & Sibanda, S. The effects of drying temperature on chemical composition and nutritive value of some tropical fodder shrubs. Agroforestry Systems 59, 231–241 (2003). https://doi.org/10.1023/B:AGFO.0000005224.64208.42
Issue Date:
DOI: https://doi.org/10.1023/B:AGFO.0000005224.64208.42
- Acacia
- Calliandra
- Digestibility
- Fodder quality
- Leucaena
- Tannins