The product tested (Palbio 50 RD, Bioibérica, S. A., Barcelona, Spain) is a coproduct of the heparin industry obtained from clean endothelial and mucosal digestive tissues of pigs free of digesta content. The fresh tissues are washed with hot water before heparin extraction, and then the mucosa is digested, solubilized, and sterilized via an enzymatic process under controlled conditions of time, temperature, and pH. The hydrolyzed mucosa is sprayed into high protein SBM at an approximate proportion of 30% to facilitate the handling. Then, the commercial product is dried using a fluid bed system that prevents structural damages of the protein fraction. The calculated AMEn (3,050 kcal/kg) and the total tract digestibility of the key indispensable AA of the HPM used for the formulation of the diets were those indicated by the