Abstract
The objectives of this study were to evaluate the effect of diet on the colonisation by Campylobacter jejuni of the chick caeca, and to determine whether the viscosity of the intestinal contents and mucin carbohydrates were altered by the diet. The diets investigated were maize based, wheat-based or wheat-based supplemented with xylanase. The xylanase-supplemented diet reduced the viscosity and lowered the numbers of Camp. jejuni. Feeding the enzyme-supplemented diet increased the amount of neutral and sulphated mucins in the goblet cells of the small and large intestines and caecum. An abundance of sulphated and carboxylated mucins was seen in the surface goblet cells of the large intestine with the maize- and wheat-based diets. Both the diet supplemented with xylanase and the maize diets increased crypt-surface glycosylation of the sialic acid residues. The analysed data from the combined sites showed significant differences in the amount of neutral and acidic mucins when comparing the wheat and the wheat plus xylanase diets. However, no changes were shown in the staining intensity of sulphated mucins between the three diets. Significant differences in the glycosylation of sialic acid and in the N-acetylglucosamine residues were shown between dietary groups. These results provide evidence that the wheat diet supplemented with xylanase leads to greater changes in the mucin composition and carbohydrate expression of goblet cell glycoconjugates, which are associated with a reduction in intestinal viscosity and decreased numbers of Camp. jejuni.