This study was conducted to evaluate the effects of the fiber source (wheat bran [WB] or sugar beet pulp [SBP]) and xylanase supplementation on production, egg quality, ileal digestibility, intestinal morphology, and gastrointestinal pH in aged laying hens. A total of 540 laying hens (Lohman LSL Lite; 70 wk of lay) were randomized into 10 treatments (6 replicate cages of 9 birds) consisting of a corn soy control supplemented with 0, 3, or 6% WB or SBP with or without xylanase (100 mg of xylanase preparation per kg) for a period of 9 wk in a 5 ! 2 factorial arrangement. Hens fed with the diets containing either of the levels of SBP or 6% WB had lower hen-day production, and addition of the enzyme improved hen-day production (P , 0.05), but it could not compensate for the lost t production due to the higher levels of either of the fiber sources. Supplementation of 6% SBP to the control diet decreased egg mass (P , 0.05). All fiber-supplemented diets significantly decreased ADFI, which was restored on enzyme addition, with the exception of 3% WB diet. Treatments had no effects on egg weight, feed conversion ratio, egg quality, and serum and carcass traits, except for ileum weight, which was greater in hens fed with the 6% SBP diet (P , 0.05). Adding 3% SBP increased ileal DM digestibility (P , 0.05). Addition of 3% WB improved jejunal villus height, villus height-to-crypt depth ratio, and villus surface area (P , 0.05). Villus surface area, DM, organic matter, and protein digestibility increased as a result of enzyme supplementation (P , 0.05). Cecal pH was reduced on feeding diets containing 3% WB, containing 3% SBP, and with enzyme supplementation (P , 0.05). In conclusion, addition of 3% WB in a corn soy control diet has the potential to improve small intestine morphology in older hens without adverse effects on performance, especially if accompanied by the use of an enzyme, which simultaneously improved morphological traits and nutrient digestibility.
