Ruiz-Arias, Nelson C., Su A Lee, Hans H. Stein. 2024. Standardized ileal digestibility of amino acids and concentration of metabolizable energy in three sources of corn protein fed to weanling pigs. J. Anim. Sci Vol. 102, Suppl. S2. P 94 - 95. doi.org/10.1093/jas/skae102.106 Link to abstract.

Cristobal, Minoy, Su A Lee, Andrea P. Mallea, Leidy J. Torres-Mendoza, Jessica P. Acosta, Carl M. M. Parsons, Hans H. Stein. 2024. Effect of feeding intact protein from soybean meal instead of crystalline amino acids on growth performance, protein synthesis, and immune response of growing pigs. J. Anim. Sci Vol. 102, Suppl. S2. P 45 - 46. doi.org/10.1093/jas/skae102.054 Link to abstract.

Apparent ileal digestibility (AID) of amino acids (AA) is affected by dietary AA levels because of different contributions of endogenous AA to the ileal digesta from pigs fed diets with different levels of AA. Because of the influence of dietary protein and AA on calculated values for AID, values for AID obtained in individual feed ingredients are not always additive in mixed diets. Therefore, values for standardized ileal digestibility (SID) of AA, which are corrected for the basal ileal endogenous losses of AA, are used in diet formulations to avoid the influence of endogenous AA on digestibility values, and SID values are, therefore, additive in mixed diets.

When the direct procedure is used to determine AA digestibility, diets containing cereal grains are sometimes formulated to contain AA below the requirement. In contrast, if the SID of oilseed meals or other protein-rich ingredients are determined, concentrations of AA may be at or above the requirement. Because the influence of the basal endogenous losses of AA is eliminated in the calculations of SID values, it is assumed that values for SID are not influenced by dietary concentrations of AA. However, to our knowledge this hypothesis has not been experimentally verified, but it is an important question because it may influence how diets used in digestibility experiments are formulated. Therefore, four experiments were conducted to test the hypothesis that the SID of AA by growing pigs is not influenced by dietary AA levels.

Cristobal, Minoy A., Carl M. M. Parsons, Hans H. Stein. 2023. Concentrations of Digestible and Metabolizable Energy, Ileal Digestibility of Amino Acids, and Digestibility of Phosphorus in a New Variety of Soybeans Fed to Growing Pigs. J. Anim. Sci. Volume 101, Issue Supplement 2, Pages 51 - 52, doi.org/10.1093/jas/skad341.056. Link to abstract.

Stein, Hans H., Olayiwola Adeola, Samuel K. Baidoo, Merlin D. Lindemann, Sunday A. Adedokun, and North Central Coordinating Committee on Swine Nutrition. 2023. Standardized ileal digestibility of amino acids differs among sources of bakery meal when fed to growing pigs. Journal of Animal Science, 101, 1–10. doi.org/10.1093/jas/skad208.

Espinosa, Charmaine D., Joaquin Cabañas-Ojeda, Edgar O. Oviedo-Rondón, and Hans H. Stein. 2023. Effects of corn hardness and drying temperature on digestibility of energy and nutrients in diets fed to growing pigs. Journal of Animal Science, 101: 1–9. doi.org/10.1093/jas/skad124. Link to full text.

Drying temperatures and corn varieties that inherently differ in kernel hardness, virtuousness, and protein solubility index may influence nutrient digestibility in corn. However, information about interactive effects of corn source (i.e., endosperm hardness) and drying method on nutrient digestibility is limited. Therefore, an experiment was conducted to test the hypothesis that the ileal digestibility of starch, crude protein (CP), and amino acids (AA) is influenced by corn source and drying temperature.

Data for the composition of wheat middlings from flour mills in the U.S. and for the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) have been published for wheat middlings from the U.S. However, it is not known if the data obtained from wheat middlings from the U.S. also are representative for wheat middlings in Europe. Therefore, an experiment was conducted to test the hypothesis that there are no differences in composition and SID of CP and AA between wheat middlings sourced from flour mills in Europe and in the U.S.

New sources of high protein corn co-products have been recently developed and may be included in diets fed to pigs. High protein corn fermented products have been evaluated in several economically important livestock species, but additional information is required with respect to the use of these products in pigs. Therefore, an experiment was conducted to test the hypothesis that the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in high protein corn fermented products and in the residual distillers dried grains and solubles (DDGS) is greater than in soybean meal (SBM).