Feed ingredients have a range in content of energy-providing macro nutrients. Especially digestibility of the crude fiber fraction has a large range in nutrient digestibility among feed ingredients. The range in fiber digestibility is directly related and inversely related to a range in digestibility of energy, the most expensive nutrient contained in swine diets. Supplemental enzymes may be beneficial to improve energy digestibility. Specific substrates and thus enzymes are beneficial for wheat and barley, but multi-enzyme cocktail were beneficial for diets based on corn and soybean meal as well. By taking the expected uplift in energy digestibility and thus energy content into consideration during least-cost diet formulation can the diet cost be reduced and should supplemental enzymes allow a cost benefit, depending on the price of the enzyme.