The hypothesis for the experiment was that feeding intact protein from soybean meal (SBM) to growing pigs instead of a combination of corn, SBM and synthetic amino acids (AA) results in greater nitrogen retention and digestible energy without affecting metabolizable energy in the diet. Feeding diets differing in SBM and synthetic AA to growing pigs placed in metabolism crates, it was possible to collect urine and feces from pigs and based on that, the digestibility of energy and nitrogen was calculated. Results demonstrated that the digestibility of energy was reduced as diet SBM inclusion was reduced, but metabolizable energy was not affected by diet. However, a reduction in daily nitrogen retention and digestibility of nitrogen was observed in diets based on synthetic AA compared with diets containing more SBM and it was concluded that SBM supports daily protein retention to a greater extent than synthetic AA.

Read the full article in the Journal of Animal Science.