Mertens David R
U.S. Department of Agriculture, Agricultural Research Service, U.S. Dairy Forage Research Center, Madison, WI 53706-1108, USA.
J AOAC Int. 2002 Nov-Dec;85(6):1217-40.
As an important constituent of animal feeds, fiber represents the portion of feeds that is bulky and difficult to digest. The neutral detergent fiber (NDF) method, developed over 30 years ago, is the method of choice for measuring total fiber in forages and other feeds. Several modifications that were made to improve its general applicability to all feeds and others developed in individual laboratories often resulted in variability among laboratories in measuring NDF. The amylase-treated NDF (aNDF) method, therefore, was developed as an accurate and precise method of measuring total insoluble fiber in feeds. A collaborative study was conducted to evaluate the repeatability and reproducibility of the aNDF method over the full range of animal feed materials. Twelve laboratories representing research, feed company, regulatory, and commercial feed testing laboratories analyzed 11 materials as blind duplicates. The materials represented feed matrixes, including animal products; high-protein, high-fat, and high-pectin feeds; oil seeds; grains; heated by-product feeds; and legume and grass hays and silages. Materials selected varied in chemical composition and contained 0-90% aNDF, 1-16% ash, 1-20% crude fat, 1-40% crude protein, and 0-50% starch. Correcting results for changes in blanks and reporting results as ash-free aNDF organic matter (aNDFom) improved the repeatability and reproducibility of results when aNDF was <25%. The within-laboratory repeatability standard deviation (Sr) for percentage aNDFom in feeds varied from 0.21 to 1.82 and among-laboratory reproducibility standard deviation (S(R)) varied from 0.37 to 2.24. The HORRAT was <2 for all materials except feed materials containing >10% fat. However, standard deviations of repeatability and reproducibility for feeds with >10% fat were similar to those of other materials. It is recommended that the aNDF method be accepted for Official First Action status.
作为动物饲料的重要组成部分，纤维是饲料中体积大且难以消化的部分。30多年前开发的中性洗涤纤维（NDF）法，是测定牧草和其他饲料中总纤维的首选方法。为提高其对所有饲料的普遍适用性而进行的几次改进，以及个别实验室开发的其他方法，常常导致各实验室在测定NDF时出现差异。因此，淀粉酶处理的NDF（aNDF）法被开发出来，作为一种准确、精确地测定饲料中总不溶性纤维的方法。开展了一项协作研究，以评估aNDF法在各类动物饲料原料中的重复性和再现性。代表研究机构、饲料公司、监管机构和商业饲料检测实验室的12个实验室对11种原料进行了盲样重复分析。这些原料代表了饲料基质，包括动物产品；高蛋白、高脂肪和高果胶饲料；油籽；谷物；加热副产品饲料；以及豆类和禾本科干草及青贮饲料。所选原料的化学成分各不相同，aNDF含量为0 - 90%，灰分含量为1 - 16%，粗脂肪含量为1 - 20%，粗蛋白含量为1 - 40%，淀粉含量为0 - 50%。当aNDF < 25%时，对空白变化进行结果校正并以无灰aNDF有机物（aNDFom）报告结果，可提高结果的重复性和再现性。饲料中aNDFom百分比的实验室内重复性标准偏差（Sr）在0.21至1.82之间，实验室间再现性标准偏差（S(R)）在0.37至2.24之间。除脂肪含量>10%的饲料原料外，所有原料的HorRat均<2。然而，脂肪含量>10%的饲料的重复性和再现性标准偏差与其他原料相似。建议接受aNDF法作为官方首次行动标准。
