The net energy of soybean meal has been estimated directly or indirectly in a number of recent experiments in the United States and other countries. In all experiments, without exception, it has been concluded that soybean meal contains more net energy than currently indicated in official feed ingredient tables. The reason for the greater net energy in soybean meal compared with current book values is likely that the digestible energy in soybean meal is underestimated in feed ingredient tables and the retention of nitrogen in modern genotypes of pigs is greater than in older genotypes, which results in a greater net energy of the protein fraction in soybean meal. As a consequence, a net energy value of soybean meal of at least 90% and maybe 100% of the net energy of corn can be assumed, which means that there is no measurable increase in net energy of diets if soybean meal is replaced by corn and crystalline amino acids.
Stein, H., J. Ibagon and M. Cristobal. 2024. Soybean Meal or Crystalline Amino Acids in Diets for Growing Pigs: Impact on Diet Net Energy, Pig Growth Performance, and Nitrogen Retention. 23rd Annual Midwest Swine Nutrition Conference Proceedings, pp. 45-51.