Vertebrate animals are holobionts and their physiology and metabolism are influenced by their commensal microbiota. Gut microbiota and their metabolites play a key role in the host defense against pathogenic microorganisms, shape the immune system, and impact the resistance to chronic disease. The metabolic activity of intestinal microbiota contributes significantly to the conversion of diet components to molecules that can be absorbed and metabolized by the host. The metabolic capacity of the intestinal microbiota by far exceeds the metabolic capacity of the hosts. Collectively, gut microbes support the digestion of the major nutrients, i.e. carbohydrates, proteins and lipids, and impact uptake and conversion of micronutrients, e.g. phenolic compounds and minerals. This chapter provides an overview on the metabolism of carbohydrates and bile salts by pig microbiota.