Dietary Formulation with Poultry by-Product Meal on a Total Amino Acid vs. a Digestible Amino Acid Basis

Previous results indicated that performance of chicks fed a high level (10%) of poultry by-product meal (PBM) was lower than performance of chicks fed a corn-soybean meal (SBM) diet. The latter difference was hypothesized to be due to variation in digestible amino acid (AA) levels among the diets. This study evaluated diets containing PBM formulated on equivalent total AA basis vs. an equivalent digestible AA basis compared to a corn-SBM diet. In this study, 7 days old male chicks were fed from 8 to 21 and 21 to 42 days of age with a corn-SBM diet or diets containing 5 or 10% PBM formulated to be equal in total or digestible AA to the corn-SBM diet. From 8 to 21 days post hatch, chicks fed 10% PBM diet formulated on a total AA basis had significantly lower (P<0.05) feed efficiency than chicks consuming the corn-SBM diet. However, formulating diets containing 5 or 10% PBM on a digestible AA basis yielded growth performance equivalent to chicks fed the corn-SBM diet. From 21 to 42 days of age, chicks fed diets containing 5 or 10% PBM formulated on a total AA had significantly lower (P<0.05) weight gain and feed efficiency than chicks consuming the corn-SBM diet. Diets containing PBM formulated on a digestible AA yielded growth performance equivalent to chicks fed the corn-SBM diet. The results of this study indicated that formulation of diets containing PBM on a digestible AA basis is superior to formulation on a total AA basis and that 10% inclusion of PBM in chick diets had no detrimental effects on performance if the diets were formulated to contain adequate levels of digestible AA.