Influence of whole wheat inclusion and xylanase supplementation on the performance, digestive tract measurements and carcass characteristics of broiler chickens

Abstract

The aim of the present study was to examine the influence of whole wheat inclusion and xylanase supplementation on the performance, digestive tract measurements and carcass characteristics of broilers fed wheat-soy diets from 1 to 35 days of age. The experiment was conducted as a 2 × 2 factorial arrangement of treatments with two wheat forms (ground wheat (GW) and whole wheat (WW) (100 and 200 g kg −1 whole wheat replacing GW during 1–21 and 22–35 days, respectively) and two levels of xylanase (0 and 1000 XU kg −1 diet). Each of the four dietary treatments was fed to four replicate pens (46 birds/pen). Whole wheat inclusion had no effect ( P>0.05) on weight gains, but reduced ( P<0.001) feed intake and lowered ( P<0.01) feed/gain. Xylanase supplementation improved weight gains with both wheat forms, but improvements in ground wheat diets were higher than those in whole wheat diets as indicated by a significant ( P<0.01) interaction between wheat form and xylanase. A significant ( P<0.001) interaction between wheat form and xylanase was also observed for feed intake. Xylanase supplementation increased feed intake in ground wheat diets, but reduced it in whole wheat diets. No significant interaction ( P>0.05) was observed for feed/gain. Xylanase supplementation lowered ( P<0.05) feed/gain, irrespective of the wheat form used by 2.5%. Whole wheat inclusion increased ( P<0.001) the relative weight of the gizzard, but decreased ( P<0.01) the relative weight of the liver. Xylanase supplementation had no effects ( P>0.05) on the relative weight of the crop, proventriculus, gizzard, pancreas, liver and heart. Neither, whole wheat inclusion nor xylanase supplementation influenced ( P>0.05) the relative weight and length of the small intestine, carcass recovery, breast muscle yield, and the relative weight of abdominal fat pad. The results suggest that substituting whole wheat for ground wheat in broiler rations is advantageous in terms of feed efficiency and that this benefit can be further exploited with xylanase supplementation.