Stein, Hans H., Olayiwola Adeola, Sung Woo Kim, Phillip S. Miller, Sunday A. Adedokun, and North Central Coordinating Committee on Swine Nutrition (NCCC-42).  2023. Digestibility of energy and concentrations of metabolizable energy and net energy varies among sources of bakery meal when fed to growing pigs. Journal of Animal Science, 101, 1–9. doi.org/10.1093/jas/skad297.

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.

To obtain accurate values for metabolizable energy (ME) in diets and ingredients, an accurate estimation of gross energy (GE) in urine is required. Urine samples are often prepared following the freeze-dried cotton-plastic bag method and GE is determined by the ignition of the sample in a bomb calorimeter. However, the concentration of GE in urine can also be determined by dripping urine on a cellulose pellet, which can then be ignited in a bomb calorimeter. Alternatively, energy in urine can be calculated from the concentration of N in urine assuming that all energy in urine originates from N. The latter 2 methods may be less expensive and less time consuming than using the freeze-dried cotton-plastic bag method. Likewise, oven drying instead of freeze drying of samples may reduce time and cost of the drying procedure. However, to our knowledge, no data comparing values for GE in urine and ME in diets among different sample preparation and drying methods are available. Therefore, the objective of this study was to test the hypothesis that there are no differences in GE of urine or ME values of diets among sample preparation methods (freeze-dried cotton-plastic bag, undried cellulose pellet, or N value method). The second hypothesis was that drying method (freeze drying or oven drying) of cotton-plastic bag urine samples from pigs do not influence analyzed the GE in urine or calculated ME in diets.

Oliveira, Maryane S. F., Markus K. Wiltafsky-Martin, and Hans H. Stein. 2020. Excessive heating of 00-rapeseed meal reduces not only amino acid digestibility but also metabolizable energy when fed to growing pigs. Journal of Animal Science, 2020, Vol. 98, No. 7, 1–9. doi:10.1093/jas/skaa219. Link to full text.

Exogenous carbohydrases can be used in diets for pigs to increase digestibility of dietary fiber and energy in cereal grains and cereal co-products. The three main fibers in cereal grains and cereal co-products are arabinoxylans, cellulose, and mixed-linked beta glucans. The fermentability is different among these three types of fiber. Energy digestibility is often improved if xylanase is added to wheat-based diets, whereas positive responses to xylanase in corn-based diets have been difficult to demonstrate, indicating that fermentation of dietary fiber differs among ingredients. However, there is less information about effects of carbohydrases on digestibility of fiber and energy in sorghum-based diets. Therefore, an experiment was conducted to test the hypothesis that xylanase and cellulase improve the digestibility of energy and total dietary fiber in diets based on corn or sorghum with addition of high fiber co-products.

Oliveira, M. S. F., J. K. Htoo, M. K. Wiltafsky, J. C. Gonzalez-Vega, and H. H. Stein. 2019. Amino acid digestibility and metabolizable energy in a heating double-low rapeseed meal fed to pigs. In: 6th EAAP International Symposium on Energy and Protein Metabolism and Nutrition, Belo Horizonte, Minas Gerais, Brazil, Sep. 9-12, 2019.

Huang, C., H. H. Stein, and G. A. Casas. 2016. Optimising soy protein concentrate use in pig diets. Pages 32-33 in Pig Progress, July 2016. Link to full text (.pdf)

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.

Espinosa, C. D. and H. H. Stein. 2018. High-protein distillers dried grains with solubles produced using a novel front-end-back-end fractionation technology has greater nutritional value than conventional distillers dried grains with solubles when fed to growing pigs. J. Anim. Sci. 96(Suppl. 2):174 (Abstr.) Link to abstract (.pdf)