Lysine is the name of the soy quality game.
Since its inception, Northern Soy Marketing (NSM) has touted the nutritional value of northern-grown soy. A recent study from South Dakota State University (SDSU), funded by NSM, has further exposed that crude protein is not the best measure of quality.
Titled “Differentiating nutritional value (energy and amino acids) of soybean meal from various origins fed to swine and poultry,” the project’s intent was to determine the nutritional value of soymeal (SBM) from different origins fed to swine and poultry. National SBM samples were obtained from the following origins: U.S. Northwest, U.S. Northeast, U.S. South and U.S. East. International samples were obtained from Brazil, Argentina and a reimported U.S. sample.
“Overall, this project aimed to advance the nutritional information and practical relevance of soybean meal nutritional value for swine and poultry,” said Jorge Perez-Palencia, the principal investigator on the project. “This data will allow the appropriate use of a specific soybean meal source in pig and broiler diet formulation to better meet nutritional requirements and consequently optimize animal performance and increase producer’s profitability.”
For decades, crude protein, a measure of nitrogen, has determined soy quality. But the tide is turning, and the language of soy quality is getting a makeover, starting with the perception crude protein is the end all be all when it comes to quality. Above all, the amount of digestible amino acids and metabolizable energy is key to quality feed. As the most abundant amino acid in soy protein, digestible lysine is the most important nutrient in feed formulation. Results from the SDSU project showed that samples from Minnesota and Nebraska had the highest lysine content, even though Brazil had the highest crude protein content.
“Crude protein level is not a suitable indicator of true nutritional value for monogastric diets,” Perez-Palencia said. “When considering international soybean meal sources, U.S. soybean meal has similar energy value compared to Argentina and Brazil soybean meals for poultry and swine.”
The final results of SDSU’s project show that the lysine content and critical amino acid level was highest for the Upper Midwest – Minnesota, South Dakota and Nebraska – compared to other regions of the U.S.
“It’s important for NSM to work with respected researchers to provide a more accurate picture of soybean feeding quality,” said Gary Williams, NSM executive director. “Partnering with SDSU is just one way that NSM is unlocking the knowledge of soy quality and highlighting the premium product being grown in the Upper Midwest.”
