SWINE FOCUS #004 Nutritional value of soy products fed to pigs

Soybeans is an important crop in the United States and are primarily used for animal feed, human food, and production of biofuels. Soybean meal (SBM) and other soy products contribute high-quality protein to diets fed to pigs because soy protein is rich in the limiting amino acids lysine, threonine, and tryptophan that are present in relatively low concentrations in the most commonly fed cereal grains. Amino acids in soy protein also have a greater digestibility by pigs than amino acids in most other commonly fed protein sources. Soy products are also a significant source of energy in diets fed to pigs and soybean meal contains as much digestible and metabolizable energy as corn. Although soy is usually fed to pigs in the form of soybean meal, full fat soybeans may be included in the diets to increase the energy density of the diet. Due to the high fiber content of soy hulls, the energy concentration in de-hulled soybean products is greater than in products containing hulls. The majority of the phosphorus in soy products is bound to phytic acid, which has a low digestibility to pigs, but the digestibility of phosphorus in soy products may be increased to more than 60% if diets are supplemented with microbial phytase.