Lee, Su A, Hans H. Stein. 2020. Young Scholar Presentation: Digestibility of calcium and phosphorus in feed ingredients fed to gestating sows and growing pigs. J. Anim. Sci. 98(Suppl. 3): 111. doi.org/10.1093/jas/skaa054.188. (Abstr.). Link to abstract.

Lancheros, Paola, Vanessa Lagos, Hans H Stein. 2020. Enhanced torula yeast has increased nutritional value compared to fish meal when fed to weanling pigs. J. Anim. Sci.  98(Suppl. 3): 62. doi.org/10.1093/jas/skaa054.112. (Abstr.). Link to abstract.

Absorption of Ca and P by active transport in the small intestine is regulated by calcitriol, which is the active form of vitamin D (1,25-dihydroxycholecalciferol) and the hormones calcitonin and PTH. One-alpha-hydroxycholecalciferol (1-α-OH-D₃) is an active vitamin D₃ analog that does not require the second hydroxylation step for vitamin D₃ to be active. It is possible that supplementation of 1-α-OH-D₃ may increase absorption of Ca and P.

The requirement for Ca and P by gestating sows increases in late gestation compared with early- and mid-gestation because of increased needs by the developing fetuses. It is also possible that dietary concentrations of Ca and P affect the rate of absorption of Ca and P in sows but data to demonstrate this have not been reported. Therefore, the objective of this experiment was to test the hypothesis that the Ca and P concentrations in diets fed to gestating sows in late gestation and supplementation of 1-α-OH-D₃ affect apparent total tract digestibility (ATTD) and retention of Ca and P as well as the ATTD of GE and concentration of DE in diets. The second hypothesis was that there is an interaction between dietary Ca and P concentrations and supplementation of 1-α-OH-D₃ in diets fed to gestating sows.

Archs Toledo, J. L., Su A Lee, and H. H. Stein. 2020. Is the phosphorus in rye more digestible? Pork Magazine, April 8, 2020. Link to full text.

Lagos, Vanessa L., Hans H. Stein. 2020. Torula yeast has greater digestibility of amino acids and phosphorus, but not energy, compared with a commercial source of fish meal fed to weanling pigs. Journal of Animal Science, 2020, 1-9. doi:10.1093/jas/skz375. Link to full text.

Lee, Su A, and H. H. Stein. 2019. Balance calcium effect on phosphorus in late-gestation sows’ diets. National Hog Farmer. August 29, 2019. Link to full text

Soybean meal (SBM) is one of the most important protein sources in swine diets. However, most P in SBM is bound to phytate, which increases inclusion of inorganic P in diets for pigs. Use of microbial phytase may hydrolyze phytate and subsequently improve P absorption. Fermex 200 (Purina Animal Nutrition, Shoreview, MN, USA) is a new source of fermented SBM that may serve as an alternative to other protein sources in diets fed to pigs. However, there are at this point no data for effects of adding phytase to diets containing Fermex 200 and no data for digestible energy (DE) and metabolizable energy (ME) concentrations of Fermex 200.

Therefore, 2 experiments were conducted to test the hypothesis that inclusion of 1,000 phytase units (FTU)/kg of microbial phytase improves the standardized total tract digestibility (STTD) of P in conventional SBM and Fermex 200. The second hypothesis was that the STTD of P, as well as concentrations of DE and ME in Fermex 200 are greater than in conventional SBM.

An enhanced torula yeast was recently developed as a natural alternative protein source to fish meal and other animal proteins. This ingredient has a lower carbon footprint than other available yeast proteins because it is derived from forestry by-products. The enhanced torula yeast has an improved amino acid (AA) profile, a greater digestibility of AA than fish meal, and an energy value that is not different from that in fish meal. However, there are no data available about the digestibility values of P in this new ingredient. Therefore, an experiment was conducted to test the hypothesis that the values for apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of P in enhanced torula yeast are not different from those in fish meal.

Lee, Su A, L. Vanessa Lagos, Carrie L. Walk, and Hans H. Stein. 2019. Basal endogenous loss, standardized total tract digestibility of calcium in calcium carbonate, and retention of calcium in gestating sows change during gestation, but microbial phytase reduces basal endogenous loss of calcium. J. Anim. Sci. 2019.97:1712–1721. Link to full text.