Banca de QUALIFICAÇÃO: ANTÔNIA RAFAELA DA SILVA OLIVEIRA

Condensed tannins from Mimosa tenuiflora as an additive in diets composed of different sources of protein.

digestibility; degradability, fractionation; condensed tannins; in vitro gas production

Several biomolecules have been studied as potential phytogenic additives in ruminant feed, enabling increased productivity and reduced environmental impacts. Considering the importance of the diversity of species available for feeding ruminants in the Semiarid region, the objective was to estimate the effect of increasing doses of condensed tannin extract (ETC) of Mimosa tenuiflora: 0, 0.5, 1.0, 1.5 , 2.0, 2.5 and 3.0% of dry matter (DM) of the diet as an additive in diets composed of different sources of protein from native species: cunhã, gliricidia and jureminha, on nutrient digestibility and ruminal parameters in vitro. The diets were composed of 65% roughage (25% tifton-85 hay, 10% elephant ear cactus and 30% one of the legumes), the concentrate represented 35% of the DM of the diet (23% crushed corn , 10% soybean meal, 1% urea and 1% commercial mineral mixture). Analyzes of chemical composition, protein fractionation, handling parameters and ruminal handling, in vitro digestibility of dry matter and ruminal handling were carried out. Legume samples for diet composition and TC removal were collected, in five replications per species, on the experimental farm of the Federal Rural University of Pernambuco (UFRPE), in the municipality of Garanhuns-PE. Protein fractionation was performed based on the Cornell Net Carbohydrate and Protein System (CNCPS).The evaluation of the degradation of organic matter and rumen fermentation products was carried out using the semi-automatic in vitro gas production technique. Rumen degradability and nutrient and protein digestibility were estimated using the two-stage technique. All species evaluated had crude protein (CP) levels above 230 g/kg DM, however the cunhã stood out with the highest levels of CP and protein fraction A (P<0.05). Gliricidia, followed by jureminha, presented the highest concentration of the B1 + B2 protein fraction (nitrogenous fraction of high and medium rumen degradation). The C fraction, which corresponds to nitrogen unavailable for animal metabolism, was higher in the jureminha species (P<0.05) and lower for the cunhã and gliricidia species. There was an interaction between the protein sources in the diet (cunhã, gliricidia and jureminha) and the TC levels for total gas production (P<0.05), however, no interaction was observed for the dietary degradation parameters. The glyricicia diet showed a high potential (P<0.05) for digestibility regardless of the addition of TC. The addition of TC from jurema preta linearly decreased the digestibility of the diets and, regardless of the addition of TC, jureminha showed lower true DM digestibility. All diets presented. The cunhã and gliricidia species had the potential to constitute part of the protein in diets formulated for ruminant animals. The addition of purified jurema preta TC extract decreased ruminal degradation rates, protecting the protein from ruminal degradation and making it available in the intestine.