Jacobs Brandy M, Patience John F, Lindemann Merlin D, Stalder Kenneth J, Kerr Brian J
Department of Animal Science, Iowa State University, Ames, 50010 USA.
Department of Animal and Food Sciences, University of Kentucky, Lexington, 40546 KY USA.
J Anim Sci Biotechnol. 2017 Apr 1;8:32. doi: 10.1186/s40104-017-0161-9. eCollection 2017.
Indigestible markers are commonly utilized in digestion studies, but the complete disappearance or maximum appearance of a marker in feces can be affected by diet composition, feed intake, or an animal's BW. The objectives of this study were to determine the impact of previous (Phase 1, P1) and current- (Phase 2, P2) diet composition on marker disappearance (Cr) and appearance (Ti) in pigs fed 3 diets differing in NDF content.
When pigs were maintained on the 25.1, 72.5, and 125.0 g/kg NDF diets, it took 5.1, 4.1, and 2.5 d, respectively, for Cr levels to decrease below the limit of quantitation; or 4.6, 3.7, or 2.8 d, respectively, for Ti to be maximized. These effects were not, however, independent of the previous diet as indicated by the interaction between P1 and P2 diets on fecal marker concentrations ( < 0.01). When dietary NDF increased from P1 to P2, it took less time for fecal Cr to decrease or fecal Ti to be maximized (an average of 2.5 d), than if NDF decreased from P1 to P2 where it took longer for fecal Cr to decrease or fecal Ti to be maximized (an average of 3.4 d).
Because of the wide range in excretion times reported in the literature and improved laboratory methods for elemental detection, the data suggests that caution must be taken in considering dietary fiber concentrations of the past and currently fed diets so that no previous dietary marker addition remains in the digestive tract or feces such that a small amount of maker is present to confound subsequent experimental results, and that marker concentration have stabilized when these samples are collected.
难消化标记物常用于消化研究，但粪便中标记物的完全消失或最大出现量可能会受到饮食组成、采食量或动物体重的影响。本研究的目的是确定先前（第1阶段，P1）和当前（第2阶段，P2）饮食组成对饲喂3种中性洗涤纤维（NDF）含量不同日粮的猪标记物消失（铬，Cr）和出现（钛，Ti）的影响。
当猪分别采食含25.1、72.5和125.0 g/kg NDF的日粮时，Cr水平分别需要5.1、4.1和2.5天降至定量限以下；或Ti分别需要4.6、3.7或2.8天达到最大值。然而，如P1和P2日粮对粪便标记物浓度的交互作用所示（P<0.01），这些影响并非独立于先前的日粮。当日粮NDF从P1增加到P2时，粪便Cr降低或粪便Ti达到最大值所需的时间比NDF从P1降低到P2时更短（平均2.5天），后者粪便Cr降低或粪便Ti达到最大值所需的时间更长（平均3.4天）。
由于文献报道的排泄时间范围广泛，且元素检测的实验室方法有所改进，数据表明，在考虑过去和当前饲喂日粮的膳食纤维浓度时必须谨慎，以便消化道或粪便中不存在先前添加的饮食标记物，以免少量标记物干扰后续实验结果，并且在采集这些样本时标记物浓度已稳定。
