It is important that the digestibility of Ca in Ca sources is known to formulate diets based on values for digestible Ca rather than total Ca. Only a small amount of the Ca required by pigs is provided by plant-based ingredients and supplementation of Ca from Ca phosphates and Ca carbonate, is usually required to meet the requirement by pigs. In addition, use of microbial phytase increases Ca digestibility in Ca carbonate, which is one of the major sources of Ca in pig diets.

Differences in Ca digestibility in 4 sources of Ca carbonate produced in the United States have been observed, but it is unknown if there are differences in the ATTD of Ca in calcium carbonate sources produced outside the United States. Therefore, the objective of this experiment was to test the hypothesis that there are differences in the apparent total tract digestibility (ATTD) and standardized total tract digestibility (STTD) of Ca and in the response to microbial phytase among 20 sources of Ca carbonate obtained from different parts of the world.

Field peas (Pisum sativum L.) are an annual season grain legume crop and are cultivated in areas that are too cold for the cultivation of soybeans. Market opportunities for field peas have increased in recent years, and the cost of cultivation is less for peas than for soybeans. The concentration of starch in field peas is less, but crude protein and amino acids are greater than in cereal grains. Therefore, in addition to providing amino acids, field peas also provide energy to swine diets, which is important because energy is the most expensive component in diets. As a consequence, it is important to determine the energy value of field peas. Agronomic practices, growing location, and differences among varieties may impact the nutritional properties of field peas, including energy digestibility. It was also observed that in-vitro energy digestibility of field peas was increased by reducing the particle size. However, there is no information on the effects of reducing particle size on concentrations of digestible energy (DE), metabolizable energy (ME), or net energy (NE) in field peas fed to group-housed pigs. Likewise, the digestibility of energy in field peas grown in the U.S. has not been compared with the digestibility of energy of field peas grown in Canada. Therefore, the objective of this research was to test the hypothesis that the particle size of field peas and the location where field peas were grown may affect the apparent total tract digestibility (ATTD) of gross energy (GE) and concentration of NE in field peas fed to growing pigs.  

Corn is the primary grain used in pig diets and provides most energy to the diets. Because energy is the most expensive component in diet formulation, it is critical to accurately determine energy concentrations in corn. Use of exogenous phytase in pig diets has been a standard and most phytase is expected to generate extra-phosphoric effects that result in increases in minerals, amino acid, or energy digestibility. Therefore, phytase companies have provided customers with matrix values that can be used for down specs of energy and nutrients in diet formulation. It is thus important to confirm if dietary phytase releases energy and other nutrients as suggested before using them. To our knowledge, however, there is no information on how much phytase can increase net energy (NE) in corn when fed to group-housed pigs. Therefore, the objective of this experiment was to test the hypothesis that addition of microbial phytase to a corn-based diet increased the apparent total tract digestibility (ATTD) of gross energy (GE) and concentration of NE by group-housed growing pigs.

Cristobal, M., S. A. Lee, and H. H. Stein. 2023. Evaluation of soybean expellers fed to growing pigs. National Hog Farmer, On-line edition, March 23, 2023.

Soybean meal (SBM) is the major source of amino acids (AA) and energy in diets for swine throughout the world. However, due to the emergence of feed-grade crystalline AA, it is estimated that SBM usage by pigs has been reduced by at least 35% over the last 25 years. Reduction on concentration of SBM and increasing the use of crystalline AA in diets may impact the digestibility of crude protein (CP) and AA. Therefore, the objective of this experiment was to test the hypothesis that diets containing corn, SBM, and crystalline AA have greater AA digestibility compared with corn and SBM diets.

Lee, S. A., and H. H. Stein. 2022. Digestibility and Availability of Nutrients in Feed Ingredients. L. I. Chiba, editor, Sustainable Swine Nutrition. 2nd rev. ed. doi:10.1002/9781119583998.ch19. Link to full text.

Lee, S. A., D. A. Rodriguez, and H. H. Stein. 2022 Microbial phytase impact on digestibility energy in growing pigs.  National Hog Farmer, On-line edition, Dec. 30, 2022.

Field peas (Pisum sativum L.) have been cultivated for centuries for human consumption, due to the high nutritional quality of pea protein. However, during the last years, increasing demand for field peas for livestock feeding has developed a market in Canada, Europe, and the U.S. Therefore, as is the case with some feed ingredients, differences in soil, varieties, agronomic practices, and growing method may change the nutritional characteristics of the peas as well as the digestibility of nutrients. Besides that, differences in the particle size of field peas may change the digestibility of nutrients. Therefore, the objective of this experiment was to test the hypothesis that the standardized ileal digestibility (SID) of crude protein (CP) and amino acids (AA) in field peas is affected by the particle size of the field peas and the region where the field peas were grown.

Lee, Su A , Leidy J. Torres-Mendoza, and Hans H. Stein1. 2022. Effects of 25-hydroxycholecalciferol (25-OH-D3) and 1-hydroxycholecalciferol (1-OH-D3) on serum bone biomarkers and calcium and phosphorus balance and concentrations of energy in diets without or with microbial phytase fed to sows in late gestation. Journal of Animal Science, 2022, 100, 1–8. doi.org/10.1093/jas/skac299.