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.

Key points:

• Retained nitrogen (g/day) of pigs was greater for the high SBM diet.
• Addition of crystalline Trp, Val, and Ile did not improve the nitrogen retention of pigs fed the DDGS and HP-DDGS diets.
• Diets containing SBM and HP-DDGS had greater DE and ME compared with DDGS diets, regardless of AA supplementation.
• The addition of crystalline AA to the low SBM diet reduced nitrogen retention.

Read the full research report here.