Extrusion results in increased digestibility of energy, which is primarily due to increased gelatinization of starch. Because this process improves flavor of cereal grains, it is known that extrusion improves palatability in pig diets. Particle size reduction in cereal grains results in an improved digestibility of nutrients due to increased surface area of grains, which subsequently increases the interaction with digestive enzymes. However, because grinding changes the textural traits of grains, the palatability of feeds is low and thus feed intake of pigs is often reduced.

The feed preference of pigs may be influenced by the characteristics of feed ingredients included in diets, but it is not known if different particle size of extruded corn affects the feed preference of weanling pigs. Therefore, the objective was to test the null hypothesis that there were no effects of reducing particle size of extruded corn on feed preference by weanling pigs.

Espinosa, Charmaine D., Joaquin Cabañas-Ojeda, Edgar Oviedo-Rondon, Hans H. Stein. 2023. Endosperm Hardness in Corn Affects the Digestibility of Energy and Fiber, and Increased Drying Temperature Reduces Amino Acid Digestibility. J. Anim. Sci., Volume 101, Issue Supplement 2, Pages 299–300, doi.org/10.1093/jas/skad341.340. Link to abstract.

Lee, Su A., Diego A. Rodriguez, Hans H. Stein. 2023. Interactive Effects of Pelleting and Particle Size Reduction of Corn on Ileal Digestibility of Starch and Amino Acids in Corn-Soybean Meal Diets Fed to Pigs. J. Anim. Sci. Volume 101, Issue Supplement, Pages 186–187, doi.org/10.1093/jas/skad341.205. Link to abstract.

Lee, S. A., D. A. Rodriguez, C. B. Paulk, H. H. Stein. 2023. Effects of pelleting and particle size reduction of corn on digestibility of starch, amino acids, fibre and fat, and concentration of net energy in corn-soybean meal diets fed to group-housed pigs. Animal - science proceedings, Volume 14, Issue 7, Pages 857-858. doi: 10.1016/j.anscip.2023.09.041.

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 energy and nutrient digestibility is limited. Therefore, an experiment was conducted to test the hypothesis that that the apparent total tract digestibility (ATTD) of gross energy (GE) and total dietary fiber (TDF) is influenced by corn source and drying temperature.

Corn is harvested at a high moisture level, and thus must be dried to less than 15% moisture to ensure safe storage. Improvements to reduce the energy consumption of the dryers have been implemented, especially by increasing the inlet air temperature. However, overheating may have a negative impact on the stability of nutrients, especially amino acids (AA), because Maillard reactions may occur if heat and moisture are applied to feed ingredients. Consequently, Maillard reactions result in a decrease in the concentration and digestibility of AA, and it is possible that energy digestibility is also reduced. Therefore, the objective of these experiments was to test the hypothesis that both the temperature used in drying and the time that heat is applied will affect the standardized ileal digestibility (SID) of AA, and concentration of digestible energy (DE) and metabolizable energy (ME) in corn fed to growing pigs.

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 evaluate the digestible energy (DE) and metabolizable energy (ME) of high protein corn fermented products and in Post MSC DDGS.

McGhee, Molly L., and Hans H. Stein. 2022. Metabolizable energy in corn is greater than in hybrid rye when fed to gestating sows, but exogenous enzymes did not increase energy digestibility. Can. J. Anim. Sci. 102: 392–395 (2022) dx.doi.org/10.1139/cjas-2021-0054. Link to full text.