Energy-dependent regulation of performance, intestinal morphology, and gene expression in broilers supplemented with glucose oxidase

Dietary energy, is a key driver of poultry performance, regulating immune function, thermoregulation, and maintenance. Glucose oxidase (GOD) is an aerobic dehydrogenase enzyme, that catalyses conversion of β-D-glucose to gluconic acid, producing hydrogen peroxide. Supplementation of GOD in animal feed has shown to improve performance, intestinal barrier function and nutrition absorption capacity. This study investigated the interactive effects of dietary energy level and GOD supplementation on performance, intestinal morphology and gene expression in broilers. A total of 384-day-old mixed sex Cobb-500 chicks were allocated to a 2 × 2 factorial design, with two energy levels (Standard: based on Cobb-500 broiler specifications and low: 80 kcal below Standard diet), with or without GOD supplementation (200g/T), each with eight replicates. Performance parameters were measured for the overall trial period (0-35). On day 35, jejunum samples were collected for histomorphology and mRNA expression of nutrient transporters (ASCT1, GLUT2 and LAT1), enzyme production (APN) and tight junction proteins (JAM2, CLDN5 and OCLN). Data were analysed using twoway ANOVA with Tukey's test for paired comparison. Results showed that, although no significant interaction was observed between energy level and GOD dose for BWG and jejunal VH:CD ratio, GOD significantly improved BWG in overall experimental period and showed tendency for improving jejunal VH:CD ratio regardless of energy level. These results aligned with jejunal gene expression results, where low energy with GOD supplementation upregulated the expression of GLUT2- supports nutrient transport and CLDN5- indicates barrier integrity. GOD also upregulated the expression of JAM2 irrespective of energy level, which also regulates integrity. However, GOD downregulated the expression of OCLN, APN and LAT1 only in the birds fed Standard energy diets. These findings suggest that GOD may be a promising feed additive with potential to improve nutrient absorption and barrier function and enhance performance when dietary energy is insufficient.