title: Effects of quebracho tannin extract and activated charcoal on nutrient digestibility, digesta passage and faeces composition in goats.
abstract: Irrigation agriculture of hot climates suffers from rapid soil organic carbon (C) turnover, high nitrogen (N) leaching and gaseous losses. In this context, we explored the possibility of supplementing ruminants with activated charcoal (AC) and condensed tannins (CT) to increase faecal concentration of long-lived C and slowly decomposable N. For this purpose, we fed AC and quebracho tannin extract (QTE, source of CT) to goats and determined nutrient digestibility, digesta passage and composition of faeces. The feeding trial comprised three periods, with 24 male goats assigned to five treatments and a control. On dry matter (DM) basis, the basal diet (control) consisted of 50% hay, 46.5% crushed maize and 3.5% soya bean meal. Treatment diets contained (on DM basis) 2% and 4% QTE (QTE2, QTE4), 1.5% and 3.0% AC (AC1.5, AC3.0) and a mixture of 2% QTE plus 1.5% AC (QTEAC). Samples of feed, refusals and faeces were analysed for chemical constituents; digesta passage was computed with a one-compartment Gamma-2 model from pulse-dose application of ytterbium-mordanted fibre and quantitative collection of faeces during 7 days. Compared to the control, organic matter and N digestibility were reduced with QTE2 and QTE4 (p ≤ 0.001), that of neutral and acid detergent fibre (NDFom, ADFom) decreased with QTE4, QTEAC and both AC treatments (p ≤ 0.001). Ruminal particle passage ranged from 0.051 h-1(QTEAC) to 0.056 h-1(control; p > 0.05). Apart from the correlation between total tract mean retention time and faecal C/N ratio (r = -0.35), passage parameters did not affect faeces quality. While faecal N concentration was not altered by both additives, AC enhanced faecal NDFom, ADFom and C concentrations (p ≤ 0.001). Whereas feeding up to 3% AC might slow down the decomposition of manure in the field without negatively affecting the digestive physiology of goats, including QTE seems not advantageous from a physiological and nutrient recycling perspective.
authors: Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Witzenhausen, Germany.
authors: A
authors: A
authors: Al-Kindi
authors: Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Witzenhausen, Germany.
authors: A
authors: A
authors: Schiborra
authors: Organic Plant Production and Agroecosystems Research in the Tropics and Subtropics, Universität Kassel, Witzenhausen, Germany.
authors: A
authors: A
authors: Buerkert
authors: Animal Husbandry in the Tropics and Subtropics, University of Kassel and Georg-August-Universität Göttingen, Witzenhausen, Germany.
authors: E
authors: E
authors: Schlecht
mesh_terms: D000818:Animals; D002606:Charcoal / Q000737:chemistry / Q000494:pharmacology*; D004063:Digestion / Q000187:drug effects*; D005243:Feces / Q000737:chemistry; D005769:Gastrointestinal Motility / Q000187:drug effects*; D006041:Goats / Q000502:physiology*; D008297:Male; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D013634:Tannins / Q000737:chemistry*
chemical_list: D010936:Plant Extracts; D013634:Tannins; D002606:Charcoal
keywords: arid climates; condensed tannins; digestive physiology; recalcitrant carbon; small ruminants