ABSTRACT The objective was to evaluate the digestive tract characteristics, metabolizability and nutrient retention of broilers fed diets supplemented with enzyme complex (EC). To evaluate the characteristics of the digestive tract 600 female Cobb 500 birds were used, distributed in a completely randomized design, with 5 inclusion levels of the EC (0; 100, 200, 300 and 400 g/ton) and 6 replicates of 20 birds each. To evaluate the metabolizability and the retention of nutrients 200 female Cobb 500 birds at 15 days of age were used, distributed in a completely randomized design with 5 levels of supplementation of the EC and 4 replicates of 10 birds each. No significant effects (P>0.05) were observed for the supplementation of the EC in the intestinal pH, digestive organ weight, intestinal length and metabolizable coefficients of dry matter and crude protein. The metabolizable coefficient of ethereal extract was influenced in a quadratic decreasing form (P<0.01). The metabolizable coefficients of calcium (Ca) and phosphorus (P) were influenced in a quadratic increase (P<0.01), resulting in increased Ca retention in 21.39% and P in 9.56%. Supplementation of the EC in broiler diets improves the metabolizability and retention of P and Ca, without affecting the other parameters evaluated.

RESUMO: Nas pastagens, a incidência de plantas daninhas reduz a produtividade e qualidade da forrageira. A identificação das espécies infestantes em pastagens é fundamental para a escolha do método de renovação. Assim, objetivou-se com este trabalho realizar a fitossociologia antes e após a renovação da pastagem de Brachiaria decumbens com a implantação de sistemas agrossilvipastoris. Foram avaliados 18 diferentes arranjos de cultivo para renovação da pastagem. Os sistemas de renovação foram por integração de eucalipto (nos espaçamentos de 12 x 2 ou 12 x 3 m) com milho, Brachiaria brizantha cv. Marandu (capim-marandu) e/ou Macrotyloma axillare (java), ou monocultivo e consórcio de capim-marandu e java, além da avaliação da aplicação ou não do herbicida bentazon na dose recomendada para a cultura do milho (0,72 kg ha-1). Foram avaliados frequência relativa, densidade relativa, abundância relativa, dominância relativa, índice de valor de cobertura, índice de valor de importância, massa seca e índice de similaridade. No primeiro levantamento, antes da renovação da pastagem, foram identificadas 23 espécies de plantas. Após a implantação dos sistemas agrossilvipastoris, as espécies Sida cordifolia, Lantana camara e B. decumbens foram as únicas incidentes nos levantamentos antes e após a renovação da pastagem com sistemas agrossilvipastoris. A utilização do capim-marandu e aplicação do herbicida foram eficientes no controle das plantas daninhas. Nos sistemas que continham capim-marundu e java, está última não foi encontrada no levantamento realizado um ano após a implantação.

ABSTRACT: In pastures, the incidence of weeds reduces the productivity and quality of forage. The identification of the weed species in pastures is fundamental to choose the renewal method. Thus, the objective of this work was to perform phytosociology before and after the renewal of a Brachiaria decumbens pasture, with the implantation of agrosilvopastoral systems. Eighteen different crop arrangements for pasture renewal were evaluated. The renewal systems were by eucalyptus integration (at 12 x 2 m or 12 x 3 m spacings) with maize, Brachiaria brizantha cv. Marandu (palisade grass) and/or Macrotyloma axillare (perennial horsegram), or monoculture and intercropping of palisade grass and perennial horsegram, as well as the evaluation of the application or not of the herbicide bentazon, at the recommended dose for maize crops (0.72 kg ha-1). Relative frequency, relative density, relative abundance, relative dominance, coverage value index, importance value index, dry matter and similarity index were evaluated. In the first survey, before the pasture renewal, 23 plant species were identified. After the implantation of agrosilvopastoral systems, the species Sida cordifolia, Lantana camara and B. decumbens were the only occurring ones before and after the renewal of the pasture with agrosilvopastoral systems. The use of palisade grass and the application of the herbicide were efficient in controlling weeds. In systems that contained palisade grass and perennial horsegram, the latter was not found in the survey conducted one year after the implantation.