Effect of soybean meal particle size on amino acid and energy digestibility in grower-finisher swine.

Researchers at Ohio State University used the ileal digestibility technique with grower-finisher pigs to evaluate the effects of particle size of soybean meal on amino acid and energy digestibility. Soybean meal was ground in a hammer mill to particle sizes approximate 900, 600, 300 and 150 um. The design of the experiment consisted of a 7x7 Latin square design, with two replicates, using crossbred barrows surgically fitted with a T-cannula at the distal ileum. Apparent and true digestibilities of amino acids were calculated using chromic oxide as an indigestibility marker. Results indicated that the apparent and true digestibilities of isoleucine, methionine, phenylalanine and valine increase linearly (P<0.05) as particle size was reduced. The essential amino acid true digestibility was increased from 91.0% to 92.4% as the particle size was reduced. Energy digestibility was not affected by the particle size of the soybean meal. These results suggested that a reduction in particle size of soybean meal resulted in a small increase in the digestibility of essential amino acids with less effect on the nonessential amino acids. They reported the largest improvement in digestibility was obtained when the particle size was reduced to 600 um.

Fastinger, N.D. and D.C. Mahan. 2003. Effect of soybean meal particle size on amino acid and energy digestibility in grower-finisher swine. J. Animal Sci. 81(3):697-704.