Dietary glucose oxidase supplementation improves growth performance, apparent nutrient digestibility, and serum antioxidant enzyme parameters in growing pigs

This study was conducted to investigate the effects of supplementing glucose oxidase (GOX; 1000 unit/g) to the diet of growing pigs on growth performance, apparent nutrient digestibility, faecal bacteria counts, and serum antioxidant enzyme parameters. A total of 200 growing pigs [(Yorkshire x Landrace) x Duroc] with an initial body weight of 23.3 +/- 0.33 kg were used in a 42-day trial. Pigs were randomly allotted to four dietary treatments with 10 replicate pens per treatment and five pigs (mixed sex) per pen based on the initial body weight. The dietary treatments consisted of the basal diet (control), control + 0.01% GOX, control + 0.02% GOX, or control + 0.03% GOX. One unit of GOX concentration is defined as the amount of enzyme which oxidises 1 mu mol beta-D-glucose per minute to D-gluconic acid and hydrogen peroxide at 37 degrees C and pH5.5. Body weight on day 42 (p = .035), average daily gain during days 22-42 (p = .001) and 1-42 (p = .001), average daily feed intake during days 22-42 (p = .008) and 1-42 (p = .020), apparent nitrogen digestibility on day 42 (p = .029), apparent energy retention on day 42 (p = .032), and the concentrations of serum glutathione peroxidase (p = .044) and glutathione (p = .032) on day 42 increased linearly at graduated doses of GOX increased in the diet. Therefore, supplementing GOX to the diet of growing pigs could improve the apparent nutrient digestibility and serum antioxidant enzyme parameters in a dose-dependent manner, thus improving growth performance. In this study, the suitable dosage of GOX used in the diet of growing pigs was 0.03%.