Hintz R W, Mertens D R, Albrecht K A
U.S. Department of Agriculture Research Service, U.S. Dairy Forage Research Center, Madison, WI 53706, USA.
J AOAC Int. 1996 Jan-Feb;79(1):16-22.
Use of sodium sulfite to reduce nitrogenous contamination in fiber analysis was evaluated. The effects of sodium sulfite on analytical accuracy and precision were examined for amylase-treated neutral detergent fiber (aNDF), sequentially determined acid detergent fiber (sADF), and acid detergent lignin (sADL) in animal feeds. In one experiment, 0.5 g sodium sulfite was added per sample during neutral detergent (ND) extraction. The treatment consistently reduced aNDF, sADF, and sADL values of 180 alfalfa samples and improved precision (decreased within-sample variance of replicated analyses). The greatest effect was on precision of sADL analysis, with within-sample variance reduced by more than 50%. In a second experiment, 24 animal feeds were analyzed for a aNDF, sADF, and sADL with and without addition of 0.5 g sodium sulfite per sample during ND extraction. Nitrogen contents of the recovered fiber fractions were determined. Sodium sulfite reduced fiber and lignin values and decreased nitrogen concentration in residues. Within-sample variance was lower in all analyses. In a third experiment, 23 animal feeds were analyzed for aNDF with sodium sulfite at 0, 0.25, 0.5, and 1.0 g per sample. Average aNDF of feeds was reduced by each additional increment of sodium sulfite; however, 1.0 g sodium sulfite resulted in only a slight reduction in aNDF compared with 0.5 g. Therefore, 0.5 g sodium sulfite per sample should be added to samples prior to aNDF analysis.
对使用亚硫酸钠减少纤维分析中的含氮污染物进行了评估。研究了亚硫酸钠对动物饲料中经淀粉酶处理的中性洗涤纤维（aNDF）、顺序测定的酸性洗涤纤维（sADF）和酸性洗涤木质素（sADL）分析准确性和精密度的影响。在一项实验中，在中性洗涤剂（ND）提取过程中，每个样品添加0.5克亚硫酸钠。该处理持续降低了180个苜蓿样品的aNDF、sADF和sADL值，并提高了精密度（降低了重复分析的样品内方差）。对sADL分析精密度的影响最大，样品内方差降低了50%以上。在第二项实验中，对24种动物饲料在ND提取过程中添加或不添加每个样品0.5克亚硫酸钠的情况下进行了aNDF、sADF和sADL分析。测定了回收纤维部分的氮含量。亚硫酸钠降低了纤维和木质素值，并降低了残留物中的氮浓度。所有分析中的样品内方差均较低。在第三项实验中，对23种动物饲料在每个样品分别添加0、0.25、0.5和1.0克亚硫酸钠的情况下进行了aNDF分析。随着亚硫酸钠添加量的每一次增加，饲料的平均aNDF均降低；然而，与0.5克相比，1.0克亚硫酸钠导致aNDF仅略有降低。因此，在进行aNDF分析之前，应向样品中添加每个样品0.5克亚硫酸钠。
