Diet Medication and Beta-Glucanase Affect Ileal Digesta Soluble Beta-Glucan Molecular Weight, Carbohydrate Fermentation, and Performance of Broiler Chickens Given Wheat-Based Diets

Abstract

The investigation of exogenous enzymes as alternatives to feed antibiotics in poultry is an emerging research area with increased public health awareness regarding antibiotic resistance. The objective was to evaluate the effects of diet medication and β-glucanase (BGase) on digesta soluble β-glucan depolymerization, carbohydrate fermentation, and performance of coccidiosis-vaccinated broiler chickens fed wheat-based diets. A total of 1,782 broilers were raised on litter floor pens, and each treatment was assigned to 1 pen in each room. There were 3 dietary treatments that were based on wheat as the sole grain (control, control + medication and control + BGase), and the birds were fed the respective treatments ad-libitum throughout the study. Treatments were allocated to pens arranged in a randomized complete block design and analyzed as a one-way ANOVA. The statistical significance was P ≤ 0.05. Beta-glucanase reduced the peak molecular weight, weight average molecular weight (Mw) and maximum molecular weight for the smallest 10% β-glucan molecules (MW-10%) at d 11 and 33, whereas diet medication reduced Mw and MW-10% at d 33 compared to the control. Beta-glucanase and medication reduced the ileal viscosity at d 11 compared to the control. Ileal propionic acid concentration at d 11 and cecal total SCFA, acetic, and butyric acid concentrations at d 33 were lower in the BGase supplemented diet than in the control. The effect of diet medication on carbohydrate fermentation was minimal. Diet medication increased body weight gain after d 11, whereas BGase increased the gain for the total trial period compared to the control. Feed intake was not affected by the dietary treatment. Diet medication and BGase improved feed efficiency after d 11 compared to the control. The overall response to diet medication was higher than BGase considering the broiler performance. In conclusion, diet medication and BGase depolymerized high molecular weight ileal soluble β-glucan and increased overall bird performance. The dietary BGase may benefit bird health in broilers fed wheat-based diets without medication.

Keywords: Beta-glucan, Prebiotic, Non-starch polysaccharide, Soluble fiber, Feed antibiotic