Metabolism and Nutrition: Nutrition I

The utilizable energy content of wheat distillers dried grains with solubles (wheat-DDGS) without or with supplementation of enzyme containing xylanase, amylase and protease (XAP) activities was deter­ mined for turkeys using linear regression method. A total of 126 BUT 10 male turkeys were fed a nutrient-adequate starter diet from d 1 to 14. On d 14, the birds were assigned to 6 dietary treatments consisting of 3 levels of wheat-DDGS (0, 300, or 600 g/kg) and 2 levels of XAP (0 or 250 mg/kg of diet) in a randomized complete block design with 7 replicate pens and 3 birds per replicate pen. The diets were fed for 7 d. Energy-yielding ingredients in the wheat-soybean meal reference diet were replaced by wheat-DDGS in a way that their ratios were the same across all the diets. Grab excreta samples were collected from each pen from d 18 to 20 to determine the AME of the diet by the index method. The AME or AMEn of wheat-DDGS was determined from the slope of regression of wheat-DDGS-associated energy intake (kcal) against wheat-DDGS intake (kg). Increasing the dietary inclusion of wheat-DDGS from 0 to 600 g/kg of the diet linearly decreased (P < 0.05) dry matter retention and total tract energy retention, irrespective of XAP supplementation. There were wheat-DDGS × XAP interactions (P < 0.05) on dietary AME and AMEn. Dietary AME and AMEn values decreased linearly (P < 0.05) as the level of wheat-DDGS increased in the diets without XAP, whereas there was no effect of increasing wheat-DDGS level on dietary AME or AMEn in XAP-supplemented diets. From the regression analysis, the ME values (kcal/kg DM) of wheat-DDGS without and with supplemental XAPwere 3,355 and 3,558, respectively. Corresponding MEn values (kcal/kg DM) were 3,109 and 3,294, respectively. Enzyme supplementation increased (P > 0.05) both the ME and MEn of the wheat-DDGS by 6 percent. It was concluded from the current study that the wheat-DDGS is a valuable source of ME for turkeys and that XAP supplementation can further increase energy availability from the feedstuff.