The addition of feed-grade amino acids replacing a portion of intact protein sources, such as soybean meals, reduces feed costs, nitrogen excretion, and environmental impact of swine production. However, replacing too much of the intact protein source may compromise growth performance, possibly due to limited nitrogen available to synthesize non-essential amino acids. In three experiments with varying diet formulation strategies, we observed that exceeding a standardized ileal digestible lysine:crude protein ratio of 6.5% worsened feed efficiency in 11- to 25-kg pigs. These studies validate that replacing too much of an intact protein source with feed-grade amino acids is detrimental to pig performance and a dietary balance or ratio between the requirement for lysine and crude protein of the diet is needed. When dietary crude protein is low, non-protein nitrogen or amino nitrogen can be used as a nitrogen source.

Read the full article in the Journal of Animal Science.