Dietary fiber (DF) is a feed component that has major influence in this regard. Dietary fibre
components are not digested by endogenous digestive enzymes, and consequently are the
main substrates for bacterial fermentation in the distal part of the gut. The main products of
fermentation are short chain organic acids (OA), predominantly lactate, acetate, propionate
and butyrate. The OA have been suggested to develop the growth of the digestive tract, by
stimulating epithelium cell proliferation [43]. In an acidic environment, OA can inhibit the
growth of enteric bacterial pathogens, such as Salmonella, E. coli and Clostridium species
[49-51]. Studies in pigs have shown that the various types of plant carbohydrates behave
differently in the GIT depending on their structural characteristics. Inclusion of soluble NSP
in the diet can stimulate the growth of commensal gut microbes, leading to increased
production of OA, and a lower pH in the large intestine [2]. Insoluble NSP reduce the transit
time and provide substrate that is slowly degradable by the microbiota in the distal large
intestine [38], and modulate gut morphology by increasing villus length [