In plant-based feed ingredients there is a considerable amount of P bound to phytate, limiting the amount of P that is available for utilization, but inclusion of microbial phytase in pig diets increases the digestibility of P. The negatively charged phytate molecule can chelate Ca cations resulting in formation of insoluble Ca-phytate complexes. Degradation of phytate by microbial phytase may prevent formation of these non-digestible complexes, resulting in increased Ca digestibility. It is also possible that use of exogenous phytase reduces endogenous loss of Ca. If indeed the reduced endogenous loss of Ca is a result of degradation of phytate, it is expected that increased doses of dietary phytase will linearly reduce endogenous losses of Ca, but this hypothesis has not been experimentally verified. Therefore, this experiment was conducted to test the hypothesis that increasing dietary phytase reduces basal endogenous loss of Ca and increases digestibility of P in growing pigs.

In most plant feed ingredients, the majority of P is bound to phytate, which reduces digestibility of P in pigs, and therefore, the concentration of digestible P in these ingredients is relatively low. Phytate is negatively charged in the intestinal tract and can bind both endogenous and dietary nutrients, which results in precipitation of non-digestible nutrient-phytate complexes. Therefore, it is possible that the use of exogenous phytase can also increase the digestibility of other nutrients than P. As an example, addition of exogenous phytase to diets also releases Ca from phytate, and thus, increases the digestibility of Ca. However, it has not been conclusively demonstrated that phytase also increases the digestibility of energy-generating nutrients and other minerals in diets fed to pigs and inconsistent results among experiments have been reported. Therefore, the objective of this experiment was to test the hypothesis that increasing phytase dose increases the apparent total tract digestibility (ATTD) of minerals and gross energy (GE) in corn and soybean meal-based diets fed to growing pigs.

Lee, Su A and H. H. Stein. 2021. Ca and P digestibility values aren’t accurate for formulating sow diets. Pork Magazine, On-line edition, Sep. 9, 2021. Link to full text.

Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets for pigs. Different technologies are used to develop high protein corn co-products, but in addition to providing amino acids to the diets, high protein corn co-products also provide energy to the diets. The energy concentrations in corn protein may depend on the concentrations of fat, carbohydrates, and protein in sources of corn protein. Newly developed corn proteins contain 40 to 50% crude protein. There are, however, limited data on how differences in the chemical composition of different sources of corn protein influence the concentrations of digestible energy (DE) and metabolizable energy (ME) when fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the apparent total tract digestibility (ATTD) of gross energy (GE) and concentrations of DE and ME among 3 sources of corn protein when fed to weanling pigs.

Rodriguez, Diego A.,  Su A Lee, and Hans H. Stein. 2021. Growth performance and carcass quality are not different between pigs fed diets containing cold-fermented low-oil DDGS and pigs fed conventional DDGS, but pelleting improves gain to feed ratio regardless of source of DDGS. Journal of Animal Science, 2021, Vol. 99, No. 8, 1–8. doi:10.1093/jas/skab129.

Corn coproducts produced from the fuel ethanol or the wet milling industries may be used in diets fed to pigs. Newly developed corn proteins are high protein feed ingredients with approximately 40 to 50% crude protein (CP), and corn protein may be a great source of digestible amino acids (AA) in diets fed to weanling pigs. There are, however, limited data on the digestibility of AA in different sources of corn protein fed to weanling pigs. Therefore, the objective of this experiment was to test the null hypothesis that there is no difference in the standardized ileal digestibility (SID) of AA in 3 different sources of corn protein when fed to weanling pigs.

Lee, Su A, L. Vanessa Lagos, Mike R. Bedford, and Hans H. Stein. 2021. Quantities of ash, Ca, and P in metacarpals, metatarsals, and tibia are better correlated with total body bone ash in growing pigs than ash, Ca, and P in other bones. Journal of Animal Science, 2021, Vol. 99, No. 6, 1–6. doi:10.1093/jas/skab149.

Ibagon, J. A. S. A. Lee, and H. H. Stein. 2021. Ileal Digestibility of Amino Acids Is Greater in Sunflower Expellers Than in Sunflower Meal When Fed to Growing Pigs. J. Anim. Sci. 99(Suppl. 1): 86–87. doi.org/10.1093/jas/skab054.140. Link to Abstract.

Lagos, L. Vanessa, Su A Lee, Mike R. Bedford, and Hans H. Stein. 2021. Formulating diets based on digestible calcium instead of total calcium does not affect growth performance or carcass characteristics, but microbial phytase ameliorates bone resorption caused by low calcium in diets fed to pigs from 11 to 130 kg. Journal of Animal Science, 2021, Vol. 99, No. 3, 1–11. doi:10.1093/jas/skab057.