The Effect of Carboxy Methyl Cellulose (A Soluble Polysaccharide) on the Rate of Marker Excretion from the Gastrointestinal Tract of Broilers

Abstract

Five-week-old broilers were used to estimate the retention time parameters of DM in the gastrointestinal (GI) tract. From 3 to 5 wk of age semisynthetic diets were fed with 0, 1, and 2% carboxy methyl cellulose (CMC, an indigestible soluble polysaccharide). These diets were obtained by exchanging cellulose by CMC. The cumulative excretion curves of a marker (Cr)-containing meal were fitted to the data at fecal and intestinal level, using a generalized logistic curve. The transit time (time of first appearance at site of measurement) was estimated as well as some retention time parameters (time of 50% excretion of the Cr intake; time at and rate of maximal Cr excretion). Addition of CMC decreased the transit time from mouth to feces by 60 min (0% CMC versus 2% CMC, respectively). The first differences in transit time were observed in the posterior part of the jejunum. In contrast to transit time, 2% CMC increased the time of 50% Cr excretion by 2 h. Furthermore, CMC reduced the maximal rate of marker excretion, suggesting a more intensive mixing between the Cr-containing meal and the rest of the chyme. Because the transit time was not related to shape of the excretion curves, the former should be used cautiously as an indication of the mean retention time in the GI tract. However, determination of a cumulative excretion curve at fecal level might also be erroneous, because marker entrance into the ceca may depend on dietary composition.