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.

Rojas, O. J. and H. H. Stein. 2017. Processing of ingredients and diets and effects on nutritional value for pigs. J. Anim. Sci. Biotechnol. 8:48. Link to full text

Casas, G. A., C. Huang, and H. H. Stein. 2017. Nutritional value of soy protein concentrate ground to different particle sizes and fed to pigs. J. Anim. Sci. 95:827-836. Link to full text (.pdf)

Liu, Y., D. Espinosa, J. J. Abelilla, G. A. Casas, L. V. Lagos, S. A. Lee, W. B. Kwon, J. K. Mathai, D. M.D. L. Navarro, N. W. Jaworski, and H. H. Stein. 2016. Non-antibiotic feed additives in diets for pigs. Pages 263-281 in Proceedings of the 2016 Chinese Swine Industry Symposium, Shanghai, China, October 20-21, 2016. Link to full text (.pdf)

Merriman, L. A. and H. H. Stein. 2016. Particle size of calcium carbonate does not affect apparent and standardized total tract digestibility of calcium, retention of calcium, or growth performance of growing pigs. J. Anim. Sci. 94:3844-3850. Link to full text (.pdf)

Soy protein concentrate is produced by aqueous ethanol extraction of water-soluble carbohydrates from soybean meal, followed by heat treatment. The ethanol extraction process removes soluble carbohydrates, leaving a product that contains at least 65% crude protein. Because soy protein concentrate contains reduced levels of oligosaccharides, trypsin inhibitors, and lectins compared with conventional soybean meal, it can be used in diets for weanling pigs.

Reducing the particle size of soybean meal can increase amino acid digestibility due to the increased surface area for enzymes to work on. However, there are no known data on the effect of particle size on amino acid digestibility in soy protein concentrate. Therefore, an experiment was conducted to determine the digestibility of crude protein and amino acids in soy protein concentrate ground to three different particle sizes and to compare these values to values for soybean meal and fish meal when fed to weanling pigs.

Rojas, O. J. and H. H. Stein. 2015. Use of feed technology to improve the nutritional value of feed ingredients. Page 23 in Advances in Animal Nutrition in Australia, Armidale, New South Wales, Australia, October 26-28, 2015. (Abstr.) Link to abstract (.pdf)

In poultry, the particle size of inorganic calcium sources has been shown to affect calcium retention and eggshell quality. However, little is known about the effect of particle size of inorganic calcium fed to pigs. Results of a previous experiment conducted in the Stein Monogastric Nutrition Lab indicated that calcium digestibility and retention were not affected by the particle size of supplemental calcium carbonate. A follow-up study was conducted to test the hypothesis that calcium carbonate particle does not affect growth performance by weanling pigs.

Rojas, O. J. and H. H. Stein. 2015. Use of feed technology to improve the nutritional value of feed ingredients fed to pigs. J. Anim. Sci. 93(Suppl. 2):61 (Abstr.) Link to abstract (.pdf)