Pistachio blanks are co-products from pistachio production and consist of unmarketable pistachio components including the hard outer shells, undersized or unripe kernels, hull fragments, and occasionally woody debris from pruning or sorting operations. As global pistachio production of pistachios increases increased quantities of pistachio byproducts are generated and interest in utilizing some of the co-products in livestock feeding has increased. Data from previous research indicated that pistachio shell powder can be utilized in diets for sows, but because pistachio shell powder and pistachio blanks are very high in fiber, the metabolizable energy in these ingredients fed to weanling pigs is expected to be less than in sows. However, weanling pigs may benefit from the insoluble dietary fiber in pistachio co-products to improve intestinal health, but there are no data to demonstrate effects of including pistachio blanks in diets for weanling pigs. Therefore, an experiment was conducted to test the null-hypothesis that pistachio blanks may be included in diets for weanling pigs without compromising pig growth performance. 

Soybean meal (SBM) is often included in cereal-based diets for growing pigs because it provides a well-balanced profile of digestible amino acids (AA), which maximizes growth performance and protein synthesis. However, in recent years, SBM has often been partially replaced by crystalline AA or alternative protein sources such as corn distillers dried grains with solubles (DDGS) or corn protein. These co-products are by-products of the ethanol and vegetable oil industries and are commonly used in swine diets due to their availability and lower cost. Although they provide some indispensable AA, they have a less balanced AA profile and greater fiber concentrations than SBM, which may result in reduced AA digestibility, nitrogen retention, and energy utilization in pigs. However, pigs have become leaner and have greater requirements for dietary AA to support protein synthesis. In addition, it is often assumed that replacing SBM with corn and crystalline AA increases the energy of the diet, but recent data indicate that SBM may provide as much or more digestible energy (DE) and metabolizable energy (ME) than previously estimated. Therefore, it is possible that replacing SBM with corn co-products and crystalline AA may result in a reduction of nitrogen and energy utilization and increase nitrogen excretion in manure. Therefore, the objective of this work was to test the hypothesis that feeding intact protein from SBM to growing pigs, instead of combinations of SBM with crystalline AA or co-products such as DDGS or corn protein, results in greater nitrogen retention and greater DE in the diet without affecting ME.

Acosta, Jessica P., Hans H. Stein. 2025. The use and application of hybrid rye in diets for weanling, growing, and reproducing swine: A review. Animal Feed Science and Technology 328 (2025) 116442. doi.org/10.1016/j.anifeedsci.2025.116442 Link to full text.

M. Cristobal , P.L. Utterback , H.H. Stein, C.M. Parsons. 2025. True metabolizable energy, standardized amino acid digestibility, phosphorus digestibility, and phosphorus bioavailability of fermented soybean meal and fermented full-fat soybeans fed to chickens. Poultry Science 104 (2025) 105386. doi.org/10.1016/j.psj.2025.105386  Link to full text.

Soybean meal (SBM) is a source of P in diets for swine. However, the P in SBM is stored as part of phytate, and pigs have very limited production of endogenous phytase. Therefore, to improve P availability, commercial pig diets often include supplemental phytase. This practice increases P digestibility, decreases the need for added phosphate, reduces feed costs, and decreases phosphorus excretion in manure. The release of P from phytate in SBM is believed to be in a dose-response manor. In addition, the destruction of phytate that is caused by phytase will also result in release of inositol, which is a sugar that may improve growth performance of pigs. However, there is very limited knowledge about how different levels of phytase influence plasma concentrations of inositol in growing pigs. Therefore, the objective of this work was to test the hypothesis that inclusion of microbial phytase in diets for growing pigs containing SBM will improve the digestibility of P in a dose-response manner and that inclusion of microbial phytase in diets for growing pigs also will increase plasma inositol levels of pigs.

Acosta, Jessica P., Lia Guardiola, Neil W. Jaworski, Hans H. Stein. 2025. Soluble dietary fiber, insoluble dietary fiber, and total dietary fiber in feed ingredients used in swine diets. Journal of Animal Science, Volume 103, Issue Supplement_1, May 2025, Pages 274–275, doi.org/10.1093/jas/skaf102.305 Link to abstract.

Guerrero Huerta, Diego, Maria A. Perez Alvarado, Luis H. Lopez Hernandez, Irma E. Candanosa Aranda, Jose A. Cuaron Ibarguengoytia, Hans H. Stein. 2025. Influence of dietary vitamin concentrations and of 25(OH)D₃ in diets for growing-finishing pigs. Journal of Animal Science, Volume 103, Issue Supplement_1, May 2025, Pages 155–156, doi.org/10.1093/jas/skaf102.166 Link to abstract.

Mallea Ortiz, Andrea Paola P., Hans H. Stein. 2025. Effect of dietary leucine on the tryptophan requirement in diets for 25-50 kg growing pigs fed soybean meal or corn fermented protein. Journal of Animal Science, Volume 103, Issue Supplement_1, May 2025, Pages 105–106, doi.org/10.1093/jas/skaf102.113 Link to abstract.

Kim, Yeonwoo , Su A Lee, Hans H. Stein. 2025. Digestibility of energy and concentrations of digestible and metabolizable energy in diets containing pistachio blanks fed to growing pigs. Journal of Animal Science, Volume 103, Issue Supplement_1, May 2025, Pages 93–94, doi.org/10.1093/jas/skaf102.100 Link to abstract.