Lack of interaction between dietary threonine and Eimeria acervulina in chicks

The production function of interest (e.g., feed cost/unit of body weight or feed cost/unit of meat) typically dictates nutrient levels of amino acids in broiler diets. Hence; broiler companies maximizing saleable white meat may have higher nutrient minimums for the most limiting amino acids than companies focusing on live body weight. Knowledge of gastrointestinal development and function, as affected by dietary amino acids, is increasing, but this knowledge is typically not considered when setting amino acid minimums in least-cost formulation. Because the gastrointestinal tract has been shown to have a high metabolic need for Thr, two experiments were conducted to determine if growth responses of broilers to dietary Thr are affected by Eimeria acervulina infection. In both experiments, Ross x Ross 308 male broiler chicks received diets containing 0.6, 0.7, and 0.8%d total dietary Thr with and without E. acervulina infection. Positive and negative main effect growth responses occurred for increasing dietary Thr and administration of E. acervulina. innoculum, respectively. Treatment interactions, however, did not occur. These results indicate that broiler chick Thr needs are not increased by a mild E. acervulina infection.