Broiler Chicken Response to Xylanase and Rice Bran Supplementation in Wheat- and Maize-Based Diets

A 28-day study involving 448 male Ross 308 broilers aimed to determine the effect of dietary rice bran (RB) and xylanase (XYL) in maize- and wheat-based diets on chicken growth, N-corrected apparent metabolizable energy (AMEn), and nutrient availability. Two isonitrogenic and isocaloric maize- or wheat-based basal diets (BDs) were formulated matching breeding recommendations. Each diet was then split in four parts: two parts BD was substituted with 75 g/kg RB and then one of the RB substituted and one of the original parts was supplemented with 16,000 XYL units/kg, resulting in a total of eight experimental dietary treatments. Each diet was fed to seven pens of eight birds per pen following randomization. The data were analyzed by ANOVA using a 2 × 2 × 2 factorial design (cereal type × RB × XYL). Enzyme supplemented RB-free wheat-based diet had greater AMEn (p = 0.002) and fiber digestibility (p = 0.007) compared to the rest. Feeding RB reduced daily feed intake (p = 0.015) and weight gain (p < 0.001) of chicks. Birds fed wheat-based diets had greater feed efficiency, coupled with an increase in starch digestibility (SD) and energy conversion ratio (ECR). The observed differences in feed efficiency were explained only by SD and ECR.