Dietary fiber is resistant to digestion in the small intestine, but is fermented in the large intestine and the resulting short chain fatty acids provide some energy to the pig. Fermentation occurs to a greater or lesser degree depending on the chemical and physical composition of the fiber; soluble fiber is generally fermented to a greater extent than insoluble fiber.

Bulk density, swelling capacity, water binding capacity, and viscosity of diets fed to pigs vary based on the types of fiber present in the diets. Therefore, an experiment was conducted to test the hypothesis that the physicochemical characteristics of feed ingredients are correlated with the concentrations of digestible energy (DE) and metabolizable energy (ME) and the apparent total tract digestibility (ATTD) of energy, dry matter (DM), and nutrients in corn, wheat, soybean meal (SBM), canola meal, distillers dried grains with solubles (DDGS), corn germ meal, copra meal, sugar beet pulp, solka floc, and pectin.