Department of Poultry Science, Auburn University, Auburn, AL 38649.
USDA-Agricultural Research Service, National Laboratory for Agriculture and the Environment, Ames, IA 50011.
Poult Sci. 2014 Jun;93(6):1428-39. doi: 10.3382/ps.2013-03712.
An experiment consisting of 3 nearly identical trials was conducted to determine the AMEn content of distillers dried grains with solubles (DDGS) to validate 4 previously published prediction equations for AMEn of corn DDGS in broilers. In addition, prior research data were used to generate a best-fit equation for AMEn based on proximate analysis. Fifteen samples of DDGS ranging in ether extract (EE) from 4.98 to 14.29% (DM basis) were collected from various dry-grind ethanol plants and were subsequently fed to broiler chicks to determine AMEn content. A corn-soybean meal control diet was formulated to contain 15% dextrose and test diets were created by mixing the control diet with 15% DDGS at the expense of dextrose. In each trial, male Ross × Ross 708 chicks were housed in grower battery cages and received a common starter diet until the experimental period. Each cage was randomly assigned to 1 of the dietary treatments (trial 1 and trial 2: control + 6 test diets, 13 replicates per diet; trial 3: control + 3 test diets, 12 replicates per diet). Experimental diets were fed over a 6-d acclimation period, followed by a 48-h total excreta collection period. On a DM basis, AMEn of the 15 DDGS samples ranged from 1,975 to 3,634 kcal/kg. Analyses were conducted to determine gross energy, CP, EE, DM, starch, total dietary fiber, neutral detergent fiber, crude fiber (CF), acid detergent fiber, and ash content of the DDGS samples. All results were reported on a DM basis. Application of the 4 equations to the validation data resulted in root mean square error (RMSE) values of 335, 381, 488, and 502 kcal/kg, respectively. Least absolute shrinkage and selection operator technique was applied to proximate analysis data for 30 corn coproducts adapted from prior research and resulted in the following best-fit equation: [AMEn (kcal/kg) = 3,673 - (121.35 × CF) + (51.29 × EE) - (121.08 × ash); P < 0.01; R(2) = 0.70; R(2) adj = 0.67; RMSE = 270 kcal/kg]. The RMSE values obtained through validation were not consistent with the expectation of predictive performance based on internal measures of fit for each equation. These results indicated that validation is necessary to quantify the expected error associated with practical application of each individual prediction equation to external data.
进行了 3 次几乎相同的试验，以确定干酒糟及其可溶物（DDGS）的代谢能（AME）含量，验证 4 种先前发表的用于预测玉米 DDGS 在肉鸡中 AMEn 的预测方程。此外，利用先前的研究数据，基于概略分析生成了一个最适合 AMEn 的方程。从不同的干法乙醇厂收集了 15 个 EE 范围在 4.98%至 14.29%（DM 基础）的 DDGS 样本，并随后将其喂给肉鸡雏鸡以确定 AMEn 含量。设计了一种基于玉米-豆粕的对照饮食，其中含有 15%的葡萄糖，并通过用 15%的 DDGS 代替葡萄糖来制作测试饮食。在每次试验中，雄性罗斯×罗斯 708 雏鸡被饲养在育雏笼中，并在试验期间接受一种共同的起始饮食。每个笼子被随机分配到 1 种饮食处理中（试验 1 和试验 2：对照+6 种测试饮食，每种饮食 13 个重复；试验 3：对照+3 种测试饮食，每种饮食 12 个重复）。试验日粮在 6 天的适应期内进行，然后进行 48 小时的总排泄物收集期。在 DM 基础上，15 个 DDGS 样本的 AMEn 范围为 1975 至 3634 千卡/千克。对 DDGS 样本进行了分析，以确定总能、CP、EE、DM、淀粉、总膳食纤维、中性洗涤剂纤维、粗纤维（CF）、酸性洗涤剂纤维和灰分含量。所有结果均按 DM 基础报告。将这 4 个方程应用于验证数据，得到的均方根误差（RMSE）值分别为 335、381、488 和 502 千卡/千克。最小绝对收缩和选择算子技术应用于从先前研究中改编的 30 种玉米副产物的概略分析数据，得到以下最佳拟合方程：[AME（kcal/kg）=3673-（121.35×CF）+（51.29×EE）-（121.08×ash）；P<0.01；R²=0.70；R² adj=0.67；RMSE=270 千卡/千克]。通过验证获得的 RMSE 值与每个方程内部拟合度的预测性能预期不一致。这些结果表明，有必要进行验证，以量化将每个单独的预测方程应用于外部数据时与实际应用相关的预期误差。
