Particle size reduction in cereal grains often results in an improved digestibility of starch due to increased surface area of grains, which subsequently increases the interaction with digestive enzymes. Improvement in the apparent total tract digestibility (ATTD) of gross energy (GE) upon particle size reduction has also been demonstrated in corn and a number of other ingredients when fed to weanling or growing-finishing pigs.

Rodriguez, Diego A., Su A Lee, and Hans H. Stein. 2020. Digestibility of amino acids and concentrations of metabolizable energy and net energy are greater in high-shear dry soybean expellers than in soybean meal when fed to growing pigs. Journal of Animal Science, 2020, Vol. 98, No. 7, 1–8.

doi:10.1093/jas/skaa215. Link to full text.

Lancheros, J. P., C. D. Espinosa, H. H. Stein. 2020. Effects of particle size reduction, pelleting, and extrusion on the nutritional value of ingredients and diets fed to pigs: A review. Animal Feed Science and Technology 268 (2020) 114603. https://doi.org/10.1016/j.anifeedsci.2020.114603.

When soybeans are crushed, the oil may be solvent extracted and the resulting defatted soybeans are known as soybean meal (SBM). However, the oil may also be mechanically expelled from the beans and the defatted soybeans resulting from this procedure is an ingredient known as soybean expellers. The expelling procedure is less efficient in removing oil from the beans and soybean expellers, therefore, contain more residual oil than SBM. Soybean expellers can be produced using different technologies, and a new procedure involving a patented high shear dry extrusion procedure was recently developed (Insta-Pro International, Des Moines, IA). There are however, no data for the digestibility of amino acids (AA) in the soybean expellers that are produced from this procedure. Therefore, the objective of this research was to test the hypothesis that the standardized ileal digestibility (SID) of crude protein (CP) and AAis greater in soybean expellers than in SBM when fed to growing pigs.

Rodriguez, D. A., S. A. Lee, C. Jones, J. K. Htoo, and H. H. Stein. 2019. Effects of extrusion on nutrient and energy digestibility in cereal grains fed to growing pigs. In: 6th EAAP International Symposium on Energy and Protein Metabolism and Nutrition, Belo Horizonte, Minas Gerais, Brazil, Sep. 9-12, 2019. Pages 185-186. (Abstr.). Link to full text

Extrusion of cereal grains may be used to improve nutrient digestibility in cereal grains because addition of heat and pressure in combination with addition of moisture during the extrusion may gelatinize the starch, which results in an increase in starch digestibility. It is also possible that AA and energy digestibility are increased by the extrusion, but data to verify this hypothesis have not been published. Therefore, the objective of these experiments was to test the hypothesis that the ileal digestibility of AA and starch and the apparent total tract digestibility (ATTD) of ADF, NDF, and GE as well as the concentrations of DE and ME in corn, wheat, and sorghum are increased by extrusion.

Yoder, A. D., M. B. Muckey, C. R. Stark, H. H. Stein, and C. K. Jones. 2017. Determining starch gelatinization from grains collected at various locations within the extrusion process. J. Anim. Sci. 95(Suppl. 5):129 (Abstr.) Link to abstract (.pdf)

Liu, Y., D. Espinosa, J. J. Abelilla, G. A. Casas, L. V. Lagos, S. A. Lee, W. B. Kwon, J. K. Mathai, D. M.D. L. Navarro, N. W. Jaworski, and H. H. Stein. 2016. Non-antibiotic feed additives in diets for pigs. Pages 263-281 in Proceedings of the 2016 Chinese Swine Industry Symposium, Shanghai, China, October 20-21, 2016. Link to full text (.pdf)

Rojas, O. J., E. Vinyeta, and H. H. Stein. 2016. Effects of pelleting, extrusion, or extrusion and pelleting on energy and nutrient digestibility in diets containing different levels of fiber and fed to growing pigs. J. Anim. Sci. 94:1951-1960. Link to full text (.pdf)