Publication Date
1997
Description
A feeding trial was carried out to determine the effect of extractable condensed tannins (ECT) concentration and tannin astringency in tropical legumes on nitrogen (N) digestion by sheep. Test legumes were Desmodium ovalifolium (Do) and Flemingia macrophylla (Fm) which had similar concentrations of Extractable CT (9% DM) but tannins with different degree of astringency (Do, 0.6 and Fm, 0.3 g protein bound/g of ECT). Chopped sun-dried forage of each legume was sprayed with either water (control) or polyethylene glycol (PEG, 3.5% DM) to reduce ECT and fed to 8 sheep with ruminal and duodenal canulas arranged in a replicated 4 x 4 Latin Square changeover design. Greater (P<0.05) N flow to duodenum, and fecal N were observed with Fm than with Do. Estimates of escape N were similar (58 to 61%) for both legumes. Reduction of ECT with PEG in both legumes (9.0-9.4 to 4.7-5.4%) resulted in lower (P<0.05) proportion of N reaching the duodenum. Results indicate that concentration of ECT had a greater effect on N digestion by sheep than tannin astringency.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Condensed Tannins in Tropical Legumes: Concentration, Astringency and Effects on the Nutrition of Ruminants
A feeding trial was carried out to determine the effect of extractable condensed tannins (ECT) concentration and tannin astringency in tropical legumes on nitrogen (N) digestion by sheep. Test legumes were Desmodium ovalifolium (Do) and Flemingia macrophylla (Fm) which had similar concentrations of Extractable CT (9% DM) but tannins with different degree of astringency (Do, 0.6 and Fm, 0.3 g protein bound/g of ECT). Chopped sun-dried forage of each legume was sprayed with either water (control) or polyethylene glycol (PEG, 3.5% DM) to reduce ECT and fed to 8 sheep with ruminal and duodenal canulas arranged in a replicated 4 x 4 Latin Square changeover design. Greater (P<0.05) N flow to duodenum, and fecal N were observed with Fm than with Do. Estimates of escape N were similar (58 to 61%) for both legumes. Reduction of ECT with PEG in both legumes (9.0-9.4 to 4.7-5.4%) resulted in lower (P<0.05) proportion of N reaching the duodenum. Results indicate that concentration of ECT had a greater effect on N digestion by sheep than tannin astringency.
