Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway; Tine SA, 1430 Ås, Norway.
Department of Animal and Aquacultural Sciences, Norwegian University of Life Sciences (NMBU), 1430 Ås, Norway.
J Dairy Sci. 2020 May;103(5):4880-4891. doi: 10.3168/jds.2019-17778. Epub 2020 Mar 5.
The enzymatic digestibility of organic matter (EDOM) method is an in vitro multi-enzymatic method for estimating the organic matter (OM) digestibility of feeds. The EDOM method previously showed high accuracy with in vivo values for compound feeds. The aim of this study was to evaluate the precision of the EDOM method and determine its additivity, compared with the long-assumed additive property of the chemical components of compound feeds. 149 feed samples, 70 commercial compound feeds and 79 associated ingredients, were analyzed in a laboratory (lab1) for OM digestibility measured by EDOM (OMD) with 2 repetitions separated in time to estimate repeatability. Of the total samples, 49 compound feeds were further analyzed in a commercial laboratory (lab2) for OMD to determine reproducibility. The 49 compounds and their 69 associated ingredients were also analyzed by lab2 for dry matter (DM), ash, crude protein (CP), neutral detergent fiber (NDF), and starch. The EDOM method resulted in an intralaboratory correlation of 98.9% and an interlaboratory correlation of 92.6%, with no significant mean bias between the 2 laboratories tested. The formulation of compound feeds, total mixed rations, and mixtures in general assumes that their nutrient content can be calculated by adding together the nutrient supply of individual ingredients. This is of great importance in the feed industry for the creation of compound feeds. Additivity of OMD for the compound feed samples was evaluated by comparing the sum of the digestible OM (DOM) of the ingredients (predicted) with DOM estimated directly in the compound feed (observed). The regression of predicted versus observed showed a coefficient of determination (R) of 0.93 and root mean square error (RMSE) of 1.07% of total DM, with no linear bias but with a mean bias (0.83% of DM). Additivity of CP, starch, crude fat, and NDF showed an R of 0.95, 0.98, 0.95, and 0.93, and RMSE of 1.56, 1.90, 0.39, and 1.46% of DM, respectively, all presenting linear bias. Crude fat also presented mean bias. Although significant, all linear and mean bias for DOM and chemical components were within the acceptable error limits for declaration of feeds. The results demonstrate the high precision of the EDOM method and its additive property, which is an advantage for the estimation of OM digestibility in compound feeds. Moreover, results of the tests of chemical components confirm their additive property.
采用酶消化法（EDOM）是一种体外多酶法，用于估计饲料有机物（OM）的消化率。EDOM 法之前已被证明对配合饲料的体内值具有高度准确性。本研究旨在评估 EDOM 法的精密度，并确定其与配合饲料化学成分的假定可加性之间的关系。将 149 种饲料样品（70 种商业配合饲料和 79 种相关成分）在实验室（lab1）中进行分析，采用 EDOM 法（OMD）测定 OM 消化率，结果重复 2 次，以估计重复性。在总样本中，49 种配合饲料在商业实验室（lab2）中进一步进行 OMD 分析，以确定再现性。lab2 还分析了这 49 种化合物及其 69 种相关成分的干物质（DM）、灰分、粗蛋白（CP）、中性洗涤剂纤维（NDF）和淀粉。EDOM 法的实验室内相关性为 98.9%，实验室间相关性为 92.6%，两个测试实验室之间没有显著的平均偏差。配合饲料、全混合日粮和混合物的配方通常假设它们的营养成分可以通过将单个成分的营养供应相加来计算。这在饲料行业中对于配合饲料的生产非常重要。通过比较预测的可消化 OM（DOM）之和（预测）与直接在配合饲料中估计的 DOM（观察），评估配合饲料样品的 OMD 加和性。预测与观察的回归显示决定系数（R）为 0.93，总 DM 的均方根误差（RMSE）为 1.07%，没有线性偏差，但有平均偏差（DM 的 0.83%）。CP、淀粉、粗脂肪和 NDF 的加和性 R 分别为 0.95、0.98、0.95 和 0.93，DM 的 RMSE 分别为 1.56%、1.90%、0.39%和 1.46%，均存在线性偏差。粗脂肪也存在平均偏差。尽管存在显著差异，但 DOM 和化学成分的所有线性和平均偏差都在声明饲料的可接受误差范围内。结果表明，EDOM 法具有高度的精密度和可加性，这是估计配合饲料 OM 消化率的优势。此外，化学成分测试的结果证实了它们的可加性。
