Evaluation of Acid Insoluble Ash as a Marker in Digestion Studies

Abstract

The present study was conducted to confirm the usefulness of acid insoluble ash (AIA) as a marker for digestion trials with rabbits. The study compared the fecal excretion of AIA with that of chromic oxide, which has been widely used as an external marker. The diet used was commercial pellets. Water was available ad libitum. Chemical analysis of AIA was performed by boiling feeds and feces in 4N HCl for 30 min and then ashing the residue at 650°C for 6 hr. The concentrations of AIA in the feeds and feces showed that fecal recovery of AIA was almost complete: 100 ±3.02% (mean±SD, n=5). This value was approximately equal to that obtained using chromic oxide. Furthermore, there were no differences in apparent digestibility determined by the total collection and AIA ratio methods. In addition, the fecal excretion behavior of AIA was very similar to that of chromic oxide. These results suggest that AIA can be used as an effective marker in digestion studies with rabbits. © 1981, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.