The influence of dietary carbohydrates on experimental infection with Trichuris suis in pigs.

Two experiments (Exps 1 and 2) were carried out to study the effect of dietary carbohydrates on the establishment of Trichuris suis in pigs. Two experimental diets based on barley flour were used; Diet 1 was supplemented with non-fermentable carbohydrates from oat hull meal, while Diet 2 was supplemented with fermentable carbohydrates from sugar beet fibre and inulin. In Exp. 1, thirty-two pigs were allocated randomly into 4 groups. Two groups were fed Diet 1 and 2 groups were fed Diet 2. Pigs from one of each diet group were inoculated with 2000 infective T. suis eggs each and the other two groups were uninfected controls. All pigs were slaughtered 8 weeks post-inoculation (p.i.). In Exp. 2, twenty-four pigs were allocated randomly into 2 groups and fed Diet 1 or Diet 2, respectively. All the pigs were inoculated with 2000 infective T. suis eggs. Six pigs from each group were slaughtered 8 weeks p.i. and the remaining 6 pigs from each group were slaughtered 12 weeks p.i. Infections were followed by faecal egg counts and worm burdens were assessed at necropsy. Pigs fed Diet 2 had lower egg counts in both experiments; in Exp. 2 the difference was significant (P<0.05). No differences were found in worm burdens 8 weeks p.i. in both experiments, however, worms from pigs on Diet 2 were significantly shorter (P<0.0001). Pigs fed Diet 2 and slaughtered 12 weeks p.i. had significantly lower worm counts (P<0.01) compared to pigs fed Diet 1. The results indicate that fermentable carbohydrates do not affect the establishment of T. suis in naïve pigs, but result in earlier expulsion and reduced growth of the established worms. Thus, diets with highly fermentable carbohydrates may be used in the control of T. suis.