Ractopamine hydrochloride (RAC), a beta-adrenergic agonist, is the active ingredient in the feed additive Paylean® (Elanco Animal Health). Paylean has become a widely used feed additive in the swine industry for market swine due to such benefits as improved average daily gain, improved feed efficiency, increased carcass leanness and improved nitrogen and water utilization.
Iowa State University
Storlie, Mark P., "Swine Feed Efficiency: Influence of Ractopamine" (2012). Iowa Pork Industry Center Fact Sheets. 7.