Tannin Protein Interactions in Ruminants

Osborne, Nicholas John (2000). Tannin Protein Interactions in Ruminants Master's Thesis, Land and Food, University of Queensland.

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Author Osborne, Nicholas John
Thesis Title Tannin Protein Interactions in Ruminants
School, Centre or Institute Land and Food
Institution University of Queensland
Publication date 2000
Thesis type Master's Thesis
Supervisor Dr D. M. McNeill
Subjects 300000 Agricultural, Veterinary and Environmental Sciences
Abstract/Summary The major antinutritive factor in Leucaena for ruminants is condensed tannin (CT). CT bind proteins, incurring a negative effect on protein utilisation. The two major factors affecting the ability of CT to bind protein have been purported to be CT size and the pH of the reaction environment. To test these hypotheses the protein precipitating capacities of CT extracted from four promising Leucaena genotypes, L. leucocephala (K636), L. pallida (CQ3439), L. trichandra (CPI46568), and L. collinsii (OFI52/88) were assessed. L. leucocephala had approximately half the ability to precipitate protein on a g/g basis than L. pallida or L. trichandra while L. collinsii gave no measurable ability to precipitate protein (reaction environment=pH 5.0). Increasing or decreasing the pH of the reaction solution away from pH 5.0 (the isoelectric point of the protein) reduced the ability of CT from all the species to precipitate protein; the decrease being higher a pH 2.5 than at pH 7.5. At pH 2.5 L. leucocephala CT completely lost its capacity to precipitate protein. The relatively poor ability of L. leucocephala CT to bind protein at pH’s approximating those at the abomasum suggests L. leucocephala may have the greatest potential of the four Leucaena’s tested for increasing the extent of feed protein escaping ruminant degradation for later release and digestion in the small intestine, hence increasing the total amount of protein absorbed by ruminants. CT fractions from each Leucaena were also separated into individual CT’s, by size-exclusion chromatography and examined for protein precipitating capacity. In general it was found that the larger sized CT of the accessions L. pallida and L. trichandra could precipitate more protein than the smaller sized CT. This pattern was not found for L. leucocephala.
Keyword condensed tannins
tannin-protein complex
isoelectric point
bypass protein
fodder tree-legume

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
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Created: Fri, 21 Nov 2008, 17:09:32 EST