摘要
Background： 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.Results： 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（P 〈 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）.Conclusions： 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 smal amount of maker is present to confound subsequent experimental results, and that marker concentration have stabilized when these samples are col ected.
Background： 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.Results： 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（P 〈 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）.Conclusions： 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 smal amount of maker is present to confound subsequent experimental results, and that marker concentration have stabilized when these samples are col ected.
基金
the National Laboratory for Agriculture and the Environment (Ames, Iowa) for laboratory assistance. Appreciation is also expressed to H. J. Monegue and W. Patton (University of Kentucky, Lexington) for assistance in the care of pigs and to D. Higginbotham (University of Kentucky, Lexington) for help in diet preparation
and to Akey Inc. (Lewisburg, OH) and DSM Nutritional Products Inc. (Parsippany, N J) for ingredients used in the diets. Mention of a trade name, proprietary product, or specific equipment does not constitute a guarantee or warranty by the USDA, Iowa State University, or the University of Kentucky and does not imply approval to the exclusion of other products that may be suitable. The USDA is an equal opportunity provider and employer.
