Adding soybean meal to pig feed may offer advantages compared to synthetic amino acids when dealing with disease, according to research conducted by the University of Illinois and funded by the Illinois soybean checkoff.

The study was designed to investigate industry observations that pigs eating soybean meal instead of crystalline amino acids responded better when sick. Young pigs with the porcine reproductive and respiratory syndrome virus received different amounts of soybean meal in their feed, and their growth and health were monitored as they recovered. In the first week after contracting the virus, pigs with high soybean meal diets had better feed efficiency and less fever than pigs with low soybean meal diets, according to the researchers.

“Just days after getting sick, young pigs receiving 10 percent more soybean meal in their diets, a level above the standard industry range, gained weight better than pigs on the low soybean meal diets,” said Ryan Dilger, an assistant professor at the University of Illinois. “Those eating more soybean meal had lower temperatures during the first week of sickness, as well.”


Future research could allow them to quantify results for on-farm settings, said Jim Pettigrew, a University of Illinois professor. “We also would like to understand the influence of soybean meal on pigs’ immune systems to confidently make recommendations for rations for pigs at higher risk for disease.”