Effect of Added tryptophan in a Lysine Supplemented Low-Protein, Corn-Soybean Meal Diet

South Dakota's production of sunflowers has been increasing during recent years and sunflowers are now recognized as an important crop in the state. Sunflowers are an excellent source of oil, with certain varieties containing up to 40% oil. Similar to soybean meal, the by-product of sunflower oil processing is a meal which can be used as a source of protein in formulating swine rations. A previous experiment, reported in the 1983 Swine Field Day Proceedings, indicated that the limiting amino acids in a corn-sunflower meal diet are lysine, tryptophan and threonine. This study was conducted to identify the optimum level of tryptophan in a lysine fortified low-protein, corn-sunflower meal diet for young growing pigs.