Crystal Levesque, PhD
Assistant Professor - Monogastric Nutrition
Department of Animal Science
South Dakota State University, Brookings, SD
Soybeans serve as an excellent source of amino acids for pigs and are commonly incorporated into swine diets as soybean meal (SBM). However, when weaned pigs are initially exposed to soybeans or SBM a hypersensitivity reaction occurs in the small intestine resulting in a systemic allergic reaction and reduced growth performance. This sensitivity response is transient as the immune system has the capability to develop tolerance to the soy protein; therefore, feeding SBM to grow-finish pigs does not have a negative impact. Allergic response to soy protein has also been studied in humans as soybean is one of the eight major foods that are known to be responsible for 90% of food allergies. In addition to allergenic components, soybeans also contain antinutritional factors, such as trypsin inhibitor, tannins, and phytate that cause decreased digestibility by rendering other nutrients indigestible. A novel low allergenicity soybean was recently bred to contain significantly reduced levels of Kunitz trypsin inhibitor, soybean agglutinin (lectin), and Gly m Bd 28 K (P34) through the use of recessive alleles. Removal of the trypsin inhibitor and P34 could potentially result in increased digestibility of the diet, especially amino acids since trypsin inhibitor inhibits protein breakdown. Furthermore, P34 is a major allergenic protein known to cause soybean sensitivity in humans, especially neonates. Therefore, the research conducted at SDSU evaluated amino acid digestibility, gut health, and immunological response of weaned pigs fed a low allergenicity soybean.