Protease enzyme in broiler diets on the nutritional quality of soybean meals from different origins

The objective of this study was to evaluate the apparent metabolizable energy (AME), nitrogen-corrected apparent metabolizable energy (AMEn), digestible amino acids, and true ileal digestibility coefficient (TIDC) of soybean meals (SMs) from different origins, with and without the addition of protease to broiler diets. The experiment using 756 male Cobb broiler chicks, in a completely randomized design with a 10 × 2 + 1 factorial arrangement (reference diet), totaling 21 treatments with 6 replications of 6 birds each. To determine the values of AME and AMEn, the diets were provided ad libitum for 10 days, with total excreta collected during the last 5 days. The protease was added on top. For the analysis of digestible amino acids and TIDC, a basal protein-free diet was used to determine the endogenous losses of amino acids in the ileum of the birds. The results revealed significant variations in the AME and AMEn values among the soybean meals, with the addition of protease promoting increases in the AME and AMEn values. Additionally, significant differences were observed in the digestible amino acid values, which were influenced by the origin and processing of the soybean meals. Protease supplementation also improved amino acid digestibility, especially for the main essential and nonessential amino acids. In conclusion, soybean meals from different regions exhibit significant variations in terms of metabolizable energy and digestible amino acids, and the addition of protease improves both the digestibility and true ileal digestibility coefficients, resulting in increased AME and AMEn values.