  In this work, we continue the modelling of the digestion in the small
intestine, started in a previous article, by investigating the effects of
dietary fibre. We recall that this model aims at taking into account the three
main phenomena of the digestion, namely the transit of the bolus, the
degradation of feedstuffs and the absorption through the intestinal wall. In
order to study the role of dietary fibre on digestion, we model their two
principal physiochemical characteristics which interact with the function of
the small intestine, i.e. viscosity and water holding capacity. This leads us
to consider some features of digestion which have not been taken into account
previously, in particular the interrelationship between the evolution of dry
matter and water in the bolus. The numerical results are in agreement with the
positive effect of insoluble dietary fibre on the velocity of bolus along the
small intestine and on its degradation. These results highlight the negative
effect of soluble dietary fibre on digestion. Although, this model is generic
and contains a large number of parameters, to our knowledge, it is among the
first qualitative dynamical modelling of fibre influence on intestinal
digestion.
