The antinutritive effect of a carboxymethylcellulose with high viscosity on lipid digestibility in broiler chickens is not associated with mucosal damage

The condition of jejunal and ileal mucosa was examined to study whether the inhibitory effect of fibre viscosity on lipid digestibility in growing chi ckens is associated with damage to the small intestinal mucosa. Two semi-pu rified diets were prepared and fed to growing chickens from 7 to 18 days of age. A nonfermentable carboxymethylcellulose (CMC) with high viscosity was added to one diet Lipid digestibility was depressed in the birds that were fed the diet containing CMC (p = 0.021). The villi were significantly long er in the jejunum of CMC-fed chickens (p = 0.033) and the number of goblet cells per 100 mu m of villus length was raised (p = 0.082). There was no si gnificant effect on the proliferation rate of enterocytes in the jejunum an d ileum; neither did the CMC diet significantly affect the composition of m ucins in the villi. In contrast to the working hypothesis, the results indi cate that CMC may have had a beneficial instead of a detrimental effect on the condition of the small intestinal mucosa. The effect of gelling fibres on the condition of the mucosa may be dependent also on their fermentabilit y. Luminal events must be held responsible for the lowered lipid digestibil ity in broiler chickens that were fed the diet containing highly viscous CM C.