Effect Of Exogenous Protease Enzyme On Broiler Chickens’ Performance, Gene Expression In Reduced Protein - Energy Diet

Abstract

This study investigated the impact of adding exogenous protease enzyme (250 g/ton) to low-protein, low-energy diets on the performance of broiler chickens. A total of 200 Ross 308 chicks were randomly assigned to four dietary treatments, including a control group, a nutrient-deficient group, and two groups supplemented with protease enzyme. The results demonstrated that protease supplementation significantly improved body weight, weight gain, feed conversion ratio, and carcass traits. Birds receiving protease showed enhanced intestinal morphology, including increased villus height and width, and deeper crypts, indicating better nutrient absorption. Additionally, IGF-1 gene expression in liver tissue was significantly higher in the protease groups, reflecting improved growth and tissue development. The immune response to common poultry viruses was also enhanced, and gut microbiota analysis showed reduced harmful bacteria (E. coli) and increased beneficial bacteria (Lactobacillus) in protease-supplemented groups. In conclusion, the addition of exogenous protease to reduced-energy and reduced-protein broiler diets improved growth performance, immunity, intestinal health, and gene expression, suggesting it as a cost-effective strategy for optimizing poultry production.