Phytic acid is the main storage of P in plants, and most P in plant feed ingredients is bound in the phytate complex. Because pigs do not secrete phytase, an enzyme to hydrolyze inositol bonds in phytate, the utilization of P by pigs is very low. Addition of supplemental phytase to diets thus results in release of P and increases P utilization by pigs. However, all enzymes have a special recognition mechanism called specificity that works only with molecules that fit to active sites of the enzyme. Therefore, it is important to know how much of P is phytate-bound and how much of the P in a given diet is not phytate-bound.

Lagos, L. Vanessa, Su A Lee, Mike R. Bedford, and Hans H. Stein. 2021. Formulation of diets for pigs based on a ratio between digestible calcium and digestible phosphorus results in reduced excretion of calcium in urine without affecting retention of calcium and phosphorus compared with formulation based on values for total calcium. Journal of Animal Science, 2021, Vol. 99, No. 5, 1–7. doi:10.1093/jas/skab138.

Lee, Su A, M. R. Bedford, and H. H. Stein. 2021. The Ash in Metacarpals, Metatarsals, and Tibia Is Better Correlated with Total Body Bone Ash Than the Ash in Other Bones of Growing Pigs. J. Anim. Sci. 99(Suppl. 1): 46–47. doi.org/10.1093/jas/skab054.080. (Abstr.). Link to abstract.

Lee, Su A, D. A. Rodriguez, and H. H. Stein. 2021. Net energy of U.S. soybean meal greater than previouly estimated. National Hog Farmer, On-line edition, March, 2021. Link to full text.

Cristobal Romero, Minoy A., Su A Lee, Hans H. Stein. 2020. Concentrations of digestible and metabolizable energy and digestibility of phosphorus in a new source of high-protein distillers dried grains with solubles fed to growing pigs. J. Anim. Sci. 98(Suppl. 3): 187. doi.org/10.1093/jas/skaa054.331. (Abstr.). Link to abstract.

Lee, Su A, Hans H. Stein. 2020. Young Scholar Presentation: Digestibility of calcium and phosphorus in feed ingredients fed to gestating sows and growing pigs. J. Anim. Sci. 98(Suppl. 3): 111. doi.org/10.1093/jas/skaa054.188. (Abstr.). Link to abstract.

Lee, Su A, Hans H. Stein. 2020. Effects of dietary amino acid concentration on digestibility of amino acids in soybean meal and soy protein concentrate fed to growing pigs. J. Anim. Sci. 98(Suppl. 3): 65. doi.org/10.1093/jas/skaa054.118. (Abstr.). Link to abstract.

Oliveira, M. S. F., M. K. Wiltafsky, S. A. Lee, K. W. Kwon, and H. H. Stein. 2020. Concentrations of digestible and metabolizable energy and amino acid digestibility by growing pigs may be reduced by autoclaving soybean meal. Anim. Feed Sci. Technol. 114621. Link to full text.

Sunflower meal, which is the co-product derived from sunflower seeds after oil extraction, has a high concentration of digestible amino acids (AA) and fiber. The nutritive value and quality of sunflower meal is partially dependent on the degree of dehulling, the variety of the sunflower, and the oil extraction process. Sunflower seeds are initially de-hulled and then partially de-oiled using a mechanial prepress procedure. A second de-oiling procedure is performed using a solvent extraction procedure or by usign a second mechanical expelling procedure. The prepress-solvent extraction procedure results in production of sunflower oil and sunflower meal that contains 1 to 3% oil, whereas the double-press procedure results in production of sunflower oil and a sunflower product that contains 5 to 10% residual oil and commonly is referred to as sunflower expellers. Some of the hulls may be added back to the sunflower meal or the sunflower expellers resulting in differences in concentrations of total dietary fiber among sources.

The apparent ileal digestibility and the standardized ileal digestibility (SID) of crude protein (CP) and AA in individual sources of partially de-hulled sunflower meal fed to pigs have been reported. However, there are no comparative values for the SID of AA in sunflower meal produced in different parts of the world, and it is not known if the SID of AA in sunflower meal are different from those in sunflower expellers. Therefore, the objective of the current study was to test the hypothesis that there is no difference in the SID of CP and AA in different sources of sunflower meal and sunflower expellers obtained from different countries.