 Prebiotics are carbohydrates which are indigestible for the host animal.On the other hand, they are selectively fermented by beneficial gut bacteria and, therefore, support a healthy gut microflora.These include fructose oligosaccharides (FOS) including inulin, transgalactose oligosaccharides (GOS), xylooligosaccharides (XOS) and soy oligosaccharides such as stachyose, verbose and raffinose.