Exogenous enzymes in broilers fed diets: performance/Enzimas exogenas em dietas de frangos de corte: desempenho

The experiment was conducted to evaluate the effect of enzyme efficiency in diets with and without nutrient reduction on the performance of broilers. Thousand and hundred forty male broiler chicks (Cobb 500[R]) were distributed in a completely randomized design with 4 treatments in a factorial 2x2 (two diets with different nutrient densities, with and without enzyme) with 8 replications of 45 birds. The diets were: positive control (normal) and a negative control (with a reduction of 4.3% and 4.5% of metabolizable energy, 16.7% and 17.7% of calcium and 35% and 42. 7%o of phosphorus, in initial and growth phases, respectively). The enzyme supplementation consisted of a combination of phytase enzyme (100g t1) and amylase, xylanase and protease (500g t1). It was evaluated the performance of birds in phases 1 to 21 and 1 to 42 days old. In the total period, the birds fed with negative control diet with added enzyme had feed intake (5.97%), body weight (8.47%), body weight gain (8.64%) and feed conversion (2.92%) higher (P0.05) to the group fed with positive control diet with or without enzyme. It is concluded that the addition of exogenous enzymes in diets with reduced metabolizable energy, calcium and phosphorus, providing a feed intake, average live weight and weight gain similar to a diet with adequate levels for broiler. Key words: poultry, phytase, amylase, protease, xilanase. O experimento foi conduzido para avaliar a eficiencia de enzimas exogenas em dietas sobre o desempenho de frangos de corte. Um total de 1440 pintos de corte machos (Cobb 500[R]) foram distribuidos em um delineamento inteiramente casualizado em esquema fatorial 2x2 (duas dietas com diferentes densidades nutricionais; com e sem a adicao enzimatica) com 8 repeticoes de 45 aves em cada unidade experimental. As dietas com diferentes densidades nutricionais foram: controle positivo (niveis normais) e um controle negativo (com reducao de 4,3 e 4,5% de energia metabolizavel; 16,7 e 17,7% de calcio e 35 e 42,7% de fosforo, nas fases inicial e de crescimento, respectivamente). A suplementacao enzimatica consistiu da combinacao das enzimas fitase (100g t-1) e amilase, xilanase e protease (500g t'). Foi avaliado o desempenho das aves nas fases de 1 a 21 e 1 a 42 dia