Department of Poultry Science, Auburn University, AL 36849-5416, USA.
Poult Sci. 2011 Nov;90(11):2528-34. doi: 10.3382/ps.2011-01510.
An energy balance experiment was conducted to determine the AME(n) of various crude glycerin samples, and to generate an equation to predict AME(n) of crude glycerin based on its chemical composition. Dietary treatments consisted of a corn-soybean meal basal diet with no added glycerin and a basal diet supplemented with 6% glycerin. Crude glycerin samples were obtained from biodiesel production facilities throughout the United States, which use a variety of lipid products as their initial feedstock. Two identical energy balance trials were conducted. In each trial, 864 male broilers (Ross × Ross 708) were fed a common starter diet until 17 d of age when they were switched to 1 of 12 experimental diets (6 replicates per treatment) from 17 to 22 d of age, with a 48-h collection period on d 21 and 22. Nitrogen-corrected apparent metabolizable energy values of crude glycerin samples were estimated by difference, whereby AME(n) of the basal diet was subtracted from the complete diet containing the test ingredient. The AME(n) of the basal diet and US Pharmacopeia-grade glycerin were determined to be 3,085 and 3,662 kcal/kg, respectively, whereas the AME(n) of the 10 crude glycerin samples ranged from 3,254 to 4,134 kcal/kg. Two crude glycerin samples had high levels of fatty acids compared with the other samples (24 and 35% vs. <0.30%), and even though their AME(n) was higher than that of the other glycerin samples (3,806 vs. 3,611 kcal/kg, P < 0.01, respectively), their AME(n) as a percentage of gross energy (GE) was lower than that of the other samples (65.5% vs. 97.4%, respectively; P < 0.01). Including all of the glycerin samples, the stepwise regression equation to predict AME(n) was determined to be: [AME(n) (kcal/kg) = 1,605 - (19.13 × % methanol) + (39.06 × % fatty acid) + (23.47 × % glycerin)]; (R(2) = 0.25; SE = 379; P ≤ 0.01). These data indicate that glycerin is a good source of energy for broilers, and the AME(n) of glycerin is dependent on fatty acid, methanol, and water contents.
进行了一项能量平衡实验，以确定各种粗甘油样品的 AME(n)，并生成一个基于其化学成分预测粗甘油 AME(n)的方程。日粮处理包括不含甘油的玉米-豆粕基础日粮和添加 6%甘油的基础日粮。粗甘油样品来自美国各地的生物柴油生产设施，这些设施使用各种脂质产品作为初始原料。进行了两次完全相同的能量平衡试验。在每项试验中，864 只雄性肉鸡（Ross×Ross 708）饲喂普通起始日粮，直至 17 日龄，然后从 17 日龄到 22 日龄转换为 12 种试验日粮之一（每个处理 6 个重复），在第 21 天和第 22 天进行 48 小时的收集期。通过差值法估算粗甘油样品的氮校正表观代谢能值，其中基础日粮的 AME(n)从含有测试成分的全价日粮中减去。基础日粮和美国药典级甘油的 AME(n)分别确定为 3085 和 3662 kcal/kg，而 10 种粗甘油样品的 AME(n)范围为 3254 至 4134 kcal/kg。与其他样品相比，有两个粗甘油样品的脂肪酸含量较高（分别为 24%和 35%，而 <0.30%），尽管它们的 AME(n)高于其他甘油样品（分别为 3806 和 3611 kcal/kg，P<0.01），但其 AME(n)占总能（GE）的比例低于其他样品（分别为 65.5%和 97.4%，P<0.01）。包含所有甘油样品，预测 AME(n)的逐步回归方程确定为：[AME(n)（kcal/kg）=1605-（19.13×%甲醇）+（39.06×%脂肪酸）+（23.47×%甘油）]；（R²=0.25；SE=379；P≤0.01）。这些数据表明，甘油是肉鸡的良好能量来源，甘油的 AME(n)取决于脂肪酸、甲醇和水分含量。
