Two new animal proteins that are on the market are hydrolyzed porcine intestines and a spent hen-soybean meal mixture but there are no published nutritional values for these two ingredients. We wanted to determine the energy concentration and digestibility of amino acids in these ingredients," said Hans H. Stein, a University of Illinois professor of animal sciences.
"We also know that the composition and processing of chicken meal and poultry by-product meal can vary so we tested those ingredients as well," he added.