Effects of high-dose glucose oxidase on broiler growth performance, antioxidant function, and intestinal microbiota in broilers

Glucose oxidase (GOD) has been investigated as a potential additive for enhancing intestinal health and growth performance in poultry. However, limited research exists on the effects of ultra-high doses of GOD in practical poultry production. This study aimed to investigate the impact of high dietary GOD levels on broiler growth performance, antioxidant capacity, and intestinal microbiota. A total of 400 healthy, 1-day-old, slow-growing broiler chickens were randomly assigned to four treatment groups. The control group was fed a standard basal diet, while the other groups (G1, G2, and G3) were fed the basal diet supplemented with 4 U/g, 20 U/g, and 100 U/g of VTR GOD, respectively. The results showed that a dose of 100 U/g GOD significantly improved the final body weight and average daily feed intake (ADFI) (<i>p</i> < 0.05). Additionally, the G3 group exhibited a marked increase in glutathione peroxidase (GSH-Px) activity (<i>p</i> < 0.05), reflecting enhanced antioxidant function. Gut morphology remained intact across all groups, indicating no adverse effects on intestinal barrier integrity. Microbiota analysis revealed significant increases (<i>p</i> < 0.05) in Firmicutes and Verrucomicrobiota abundance at the phylum level in the GOD-supplemented groups. Moreover, GOD treatments significantly increased the abundance of <i>Faecalibacterium</i>, <i>Mucispirllum</i>, and <i>CHKCI001</i> at the genus level. Metabolic function predictions suggested that high-dose GOD supplementation enriched carbohydrate metabolism, particularly starch and sucrose metabolism. Correlation analysis indicated that <i>Faecalibacterium</i> and <i>CHCKI001</i> were two bacteria strongly influenced by GOD supplementation and were associated with enhanced growth performance and improved gut health. In conclusion, high-dose GOD supplementation had no adverse effects and demonstrated significant benefits, promoting both growth performance and gut health in broilers.