The AB Vista Signis AB Vista Signis dual action microbiome activator is designed to accelerate the development of a fibre-degrading microbiome. Signis is a unique xylanase and fermentable xylo-oligosaccharide (XOS) combination that accelerates the development of a fibre-degrading microbiome, enabling fermentation of fibre sources that would otherwise remain undigested, and improving the extent of fibre digestibility earlier in the monogastric life cycle.