Exogenous enzymes have been used in monogastric animal nutrition for improving nutrient digestion as well as ameliorating the negative effect of the antinutritional factors present in feed ingredients. This study was conducted to investigate the effect of exogenous protease on performance of broilers fed diets containing high levels of trypsin inhibitor (TI). A total of 1632 Ross 308 male broiler chicks were randomly allocated to one of four treatments with 12 replicate pens per treatment and 34 birds per replicate: All treatments were formulated using soybean meal (SBM), full fat soy (FFS) with low TI levels (3.8 and 4.7 mg/g, respectively) and 3% of raw soy with 34.0 mg/g of TI during grower and finisher phases; T1 (positive control) was formulated according to the genetic requirements. T2 (negative control) was formulated with 5% lower levels of digestible amino acids compared to T1. T3 & T4 were the same as T2 but with the addition of exogenous protease at 250 g and 500 g/MT, respectively. The calculated level of TI for starter diet was 1,38 mg/g, grower diet was 2.33 mg/g and 2.19 mg/g for the finisher. Mash diets were provided over 3 dietary phases: starter (0-7d), grower (8-21d), and finisher (22-35d). Body weight and feed intake were determined at 14, 21, and 35 d of age. Data was analyzed as one-way ANOVA, and means were separated using Tukey HSD test (P≤0.05). No differences in BWG were observed among treatments (P=0.207), while significant differences were observed for feed intake (P=0.0495) and FCR (P=0.015) between the T2 (negative control) and T4 (diets with 500 g/MT protease inclusion) for the overall period from 0-35d, T1 (Positive control) and T3 (diets with 250 g/MT protease inclusion) being intermediate. Supplementing protease at 500 g/MT decreased feed intake by 3.14% and FCR by 5 points compared to the negative control (P≤0.05), and 2.35% and 1.5 points beyond the PC for feed intake and FCR, respectively. Based on the results, supplementation of exogenous protease can improve growth performance in broilers through mitigating the negative effect of high levels of TI as well as compensating for 5% of amino acid reduction.

Torres, D., J. Prada, G. Rueda, R. Qudsieh and E. Castro. 2025. Protease supplementation can ameliorate negative effects of high trypsin inhibitor in broiler diets. 2025 Poultry Science Association Annual Meeting, Abstract 221