An experiment was conducted to evaluate the effect of an enzyme blend (EB) on the performance, diet metabolizability, phosphorus (P) retention, and bone mineralization of broilers fed diets containing 10% defatted rice bran (DRB). In total, 432 one- to 38-d-old male Cobb broilers were evaluated according to a completely randomized experimental design in 3 x 2 factorial arrangement. Three diets were tested with two nutrient reductions (NR) in the matrix (standard diet; NR I of 75 kcal/kg ME, 0.1% Ca and 0.1% available P; and NR II of 100 kcal/kg ME, 0.1% Ca and 0.1% available P) with or without the addition of an EB (200 g/t). The coefficients of total tract apparent retention (CTTAR) of the diets and P retention were determined by collecting excreta during two periods (14 to 17 and 28 to 31 d). As expected, birds fed the standard diet had higher BW, BW gain, and G:F compared to birds on the NR diets. The EB did not show any positive effects on CTTAR or on performance; however, birds fed the EB retained 6.58% more P from d 14 to 17 (p ≤ 0.07) and 8.55% from d 28 to 31 (p < 0.05). Tibiotarsus ash percentage also increased by 2.45% (p ≤ 0.06) on d 38. In diets containing 10% DRB, the enzyme blend showed biological activity improving P retention and tibiotarsus mineralization.
Broiler chicken; defatted rice bran; enzyme blend; metabolism; mineral retention; performance