Energy value of wheat dried distillers grains with solubles in roosters, broilers, layers, and turkeys

Four experiments were conducted to measure total tract metabolizability of gross energy (GE), the AME, and AME(n) or AME content corrected for a standardized N retention (AME(s)) of 10 European wheat dried distillers grains with solubles (DDGS) in roosters, broilers (3 wk old), layers (25 wk old), and growing turkeys (10 wk old). The wheat DDGS were obtained from 7 European ethanol plants and selected to get a large variability in chemical composition. The AME, AME(n), or AME(s) of wheat DDGS was obtained according to the difference method. The highest AME(n): GE was obtained for roosters with an average (minimum-maximum) value of 49% (43-55), the lowest in turkeys (43%; 34-50), and intermediate values (47%; 41-57 and 46%; 36-50) in broilers and layers, respectively. Corresponding AME(n) values were 10.3 (9.0-11.3), 9.9 (8.5-11.7), 9.6 (7.8-10.5), and 9.6 (7.8-10.5) MJ/kg of DM for roosters, broilers, layers, and turkeys, respectively. The AME(s) for N retention equal to 50% of N intake was about 0.6 MJ higher than the corresponding AME(n) value. Our data indicate that the AME(n) content of wheat DDGS can be predicted from either their acid detergent fiber content (R-2 = 0.79) or the lightness score (L*; R-2 = 0.77) with a common slope but different intercepts for the 4 poultry categories. If dark and overheated samples (L* < 50; n = 3) with the lowest AME(n): GE ratio and AME(n) values are excluded, the average AME(n): GE ratio becomes 51, 49, 48, and 45% in roosters, broilers, layers, and turkeys, respectively, with corresponding AME(n) values of 10.7, 10.2, 10.0, and 9.5 MJ/kg of DM that are more representative of a well-controlled process for DDGS preparation. The negative effect of L* on energy value and energy metabolizability indicates that overheating while drying should be minimized to maximize the energy value of wheat DDGS for poultry. Finally, equations for predicting AME values in layers, broilers, or turkeys from the AME values in roosters are proposed.