Impact of tannin extracts on Nitrogen excretions by ruminants: a meta-analysis approach

CLAUDIO A. POZO; GONZALO FERNANDEZ-TURREN; ALSIANE S. CAPELESSO; GUADALUPE B. HERNANDEZ-LUNA

Puerto Varas

Congreso; XXIV Congreso de la Asociacion Latinoamericana de Producción Animal y XL Congreso de la Sociedad Chilena de Producción Animal, SOCHIPA. A.G.; 2015

Asociación Latinoamericana de Producción Animal y Sociedad Chilena de Producción Animal

Tannins are polyphenolic compounds which interact with dietary protein reducing their ruminal degradability. In ruminant fed diets with high crude protein (CP) content, this property would shift N excretion from urine to feces what, while not affecting total organic matter digestibility (OMD), it can be positive from an environmental point of view. A statistical meta-analysis approach was conducted to quantify the effect of dietary inclusion of vegetable tannin extracts (TE) on OMD and N excretion in ruminants. A database was constructed from results of in vivo trials with ruminants fed diets containing TE from Acacia mearnsii and Schinopsis spp. Studies with lactating cows fed diets containing less than 16% of CP were excluded from the database. A total of 6 studies comprising 17 treatments were analyzed. The effect of TE was evaluated using linear regressions between dietary TE levels (% of dry matter (DM)), dietary CP content (% of DM) and either nutritional variable OMD, urinary N or fecal N excretion (g g-1 N intake). The OMD decreased linearly at increased TE concentration in feed (OMD= 96.85 - 1.06 CP - 0.22 TE, P