Most of the P in corn and soybean meal (SBM) is stored as phytate. Phytase consists of one hydroxylated inositol ring with six phosphate groups. Therefore, phytase is often included at a standard level of 500 units (FTU) per kg in swine diets to increase the release of P from phytate. However, greater concentrations of phytase in diets for pigs may benefit growth and feed efficiency, which is likely a result of the inositol that is also released and can be absorbed by pigs. Inositol is believed to increase growth of animals by stimulating protein accretion. Inositol also improves gut health of pigs by enhancing intestinal epithelial cell functions. However, data from recent research demonstrated that weaning pigs at around 21 days of age results in a dramatic drop in plasma inositol and it is not until 6 weeks post-weaning that pigs will regain preweaning levels of inositol. Therefore, an experiment was conducted to test the hypothesis that microbial phytase will release sufficient inositol from corn and SBM and other ingredients in diets for newly weaned pigs to maintain pre-weaning levels of plasma inositol throughout the post-weaning phase and that this will result in improved growth performance of pigs.

Ibagon, Jimena A., Su A. Lee, Diego A. Rodriguez, C. Martin Nyachoti, Hans H. Stein. 2024. Reduction of particle size of field peas (Pisum sativum L.) increases net energy and digestibility of starch when fed to growing pigs, but there is no difference in  nutritional value between peas from the United States and peas from Canada. J. Anim. Sci.

Marshall, C. M., S. A Lee, and H. H Stein. 2024. Feed preference of weanling pigs fed diets containing extruded corn ground to different particle sizes. J. Anim. Sci.102 (Suppl. 3): 234–235. doi.org/10.1093/jas/skae234.272 Link to abstract.

Stein, H.H. 2024. Review: Aspects of digestibility and requirements for minerals and vitamin D by growing pigs and sows. Animal 18, 101125. doi.org/10.1016/j.animal.2024.101125  Link to full text.

Vitamin D regulates a wide spectrum of genes responsible for Ca and P homeostasis and cell differentiation. Cholecalciferol, commonly known as vitamin D₃, is a primary source of vitamin D₃ in diets for growing pigs; however, it needs to be hydroxylated twice to be active. The first hydroxylation occurs in the liver at the 25-position, resulting in 25-hydroxycholecalciferol [25(OH)D₃], whereas the second hydroxylation occurs in the kidneys at the 1-position, resulting in 1,25 dihydroxycholecalciferol [1,25(OH)₂D₃], which is the active form of vitamin D₃ in the body. Supplementation of 25(OH)D₃ to diets for sows in late gestation may increase the apparent total tract digestibility (ATTD) and retention of Ca and P, but there are no data to demonstrate this effect in growing pigs.

Cereal grains commonly used in diets for pigs have low digestibility of P because P is bound to phytate. Exogenous phytase increases the digestibility of both Ca and P in pigs by releasing the P from the phytate molecule within the gastrointestinal tract of pigs. However, there is limited information about the interaction between 25(OH)D₃ and supplemental phytase in diets fed to growing pigs. Therefore, the objective of this experiment was to test the hypothesis that both 25(OH)D₃ and microbial phytase independently and in combination may increase standardized total tract digestibility (STTD) of Ca and P by growing pigs.

Ibagon, J. A., S. A. Lee, and H. H. Stein. 2024. Empirical validation of implementing high energy in soybean meal: soybean oil equivalence of soybean meal in diets fed to growing pigs. In: 75th Annual Meeting of the EAAP, Florence, Italy, Sep. 1-5, 2024.

Stein, Hans H. Jimena A. Ibagon, Minoy Cristobal. 2024. Soybean meal or crystalline amino acids in diets for growing pigs: Impact on diet net energy, pig growth performance, and nitrogen retention. Proc. 23^nd Annual Midwest Swine Nutrition Conf. Danville, IN, Sep. 5, 2024. Pages 45-51.

Cristobal, M., S. A Lee, and H. H. Stein. 2024. Diet protein concentration does not influence net energy. National Hog Farmer. On-line edition. Aug. 29, 2024. Link to full text.

Stein, Hans H. 2024. The pig is an excellent model to determine amino acid digestibility of human foods and to generate data needed to meet human amino acid requirements. Front. Nutr. 11:1434430. DOI 10.3389/fnut.2024.1434430 Link to full text.