Animal Science Department


Date of this Version

January 2001


Published in 2001 Nebraska Swine Report, compiled by Duane Reese, Associate Professor, Department of Animal Science. Prepared by the staff in Animal Science and cooperating Departments for use in Extension, Teaching and Research programs. Published by Cooperative Extension Division, Agricultural Research Division, and Institute of Agriculture and Natural Resources at the University of Nebraska-Lincoln.
Swine reports website:


An experiment was conducted to determine whether phytase additions to swine growing-finishing diets improved the availability of lysine, calcium, energy and phosphorus in corn and soybean meal-based diets. Diets investigated for growing-finishing barrows of high-lean-gain potential included: 1) University of Nebraska recommended diet formulations; 2) diets formulated to contain 85% of the lysine recommended; 3) lysine-deficient diets formulated with phytase; 4) phytase-formulated diets with phytase deleted; and 5) phytase-formulated diets with phytase deleted and with additional calcium and phosphorus. Pigs fed diets formulated to 85% of the recommended lysine level had slower growth, slower daily lean gain, poorer feed conversion, and less carcass lean. There was no effect of phytase addition or deletion on growth, feed efficiency, or carcass lean. There was no effect of phytase addition or deletion on bone strength or bone ash. These results do not agree with the large body of evidence regarding the improvement in availability of phosphorus in corn and soybean meal with the addition of phytase to swine diets and may be related to the growth impairment associated with the lysine deficiency.