Pathology of Trichuris suis infection in pigs fed an inulin- and a non-inulin-containing diet.

Pathology of the colon in pigs infected with Trichuris suis and fed an inulin and a non-inulin containing diet was studied to investigate the inflammatory response induced and the influence of inulin on this. Twenty-nine pigs were allocated into four groups (N-7, I-7, N-9 and N/I-9). Groups N-7, N-9 and N/I-9 were given a diet with non-fermentable carbohydrates, and group I-7 was fed a diet including fermentable carbohydrates (inulin). After 2 weeks, all pigs were inoculated with 2000 T. suis eggs. Seven weeks post-infection (p.i.), groups N-7 and I-7 were killed and group N/I-9 changed to inulin diet to study the influence of inulin on already established T. suis. Nine weeks p.i., groups N-9 and N/I-9 were killed. Trichuris suis were collected from the colon for enumeration. Tissues from the colon of each pig were taken for histological and immunohistochemical quantitative and semi-quantitative evaluations of heterophils, eosinophils, mast cells, IgA(+), IgG(+), IgM(+) and CD3(+) cells. The findings were compared with tissues from seven uninfected pigs of the same age. Pigs fed inulin had significantly fewer worms compared with pigs on the non-fermentable carbohydrate diet. The number of inflammatory cells in the colonic mucosa was increased in all T. suis-infected pigs compared with uninfected controls. The numbers of eosinophils, mast cells, IgA(+), IgG(+) and CD3(+) cells were significantly lower in pigs fed inulin than pigs fed non-fermentable carbohydrate. Whether this is a direct effect of inulin or a secondary effect due to the lower parasitic burden in inulin fed pigs is not known.