An experiment was conducted to study the effect of exogen carbohydrase enzymes with xylanase activity on the apparent metabolizable energy (AME) and apparent corrected metabolizable energy (AMEn) of whole rice bran (WRB). The carbohydrase enzymes with xylanase activity utilized those of commercial brand Rovabio TM Excel AP, Allzyme Rice and Ronozyme WX, denominated, respectively, in this work, of enzymes A, B, and C. A. boret 240 broilers Cobb strain aged 21 days were housed in metallic cages with excreta-collecting installed in a metabolism room with controlled atmosphere. The experimental desing was completely randomized using 4 reference-diets and 4 test-diets and 6 replicates, amounting 48 plots with 5 birds each. The reference-diets and test-diets studied were the following: Reference-diet on the basis of corn, soybean meal, vitamins and minerals (RD); RD + enzyme A; RD + enzyme B; RD + enzyme C; 70% of RD + 30% of WRB; 70% of RD + 30% of WRB + enzyme A; 70% of RD + 30% of WRB + enzyme B and 70% of RD + 30% of WRB + enzyme C. The method of total excreta collection was used (Sibbald & Slinger, 1963) for 5 days in each experimental unit, preceded of 5 days of adaptation of the birds to the diets. The determinations of AME and AMEn were accomplished according to the methodology by Matterson et al. (1965). AMEn of WRB was of 2,897 kcal/kg of DM. Using the carbohydrase enzymes the best value of AMEn of WRB was obtained when enzyme C was added, its being of 3,083 kcal/kg of DM, with a percent increase of 6.4%. The reference-diet that received the addition of enzyme C, had its AMEn increased, which did not happen when the other carbohydrases was used.
Broiler; metabolizable energy; whole rice bran
