Abstract
The condition of jejunal and ileal mucosa was examined to study whether the inhibitory effect of fibre viscosity on lipid digestibility in growing chickens is associated with damage to the small intestinal mucosa. Two semi-purified 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 longer 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 significant effect on the proliferation rate of enterocytes in the jejunum and ileum; neither did the CMC diet significantly affect the composition of mucins in the villi. In contrast to the working hypothesis, the results indicate 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 fermentability. Luminal events must be held responsible for the lowered lipid digestibility in broiler chickens that were fed the diet containing highly viscous CMC.