Effect of xylo-oligosaccharide supplementation on performance, oxidative stress and meat quality of broiler chickens fed diets containing rice bran meal

Background Xylooligosaccharides (XOS) are increasingly recognized for their capacity to selectively modulate intestinal function and enhance nutrient utilization, particularly in diets containing high-fiber or low-value feed ingredients. This study evaluated the effects of graded replacement of maize with full-fat rice bran, with or without XOS supplementation, on growth performance, oxidative status, intestinal morphology, and feed economic efficiency of finisher broiler chickens. A total of 300 birds of comparable body weight were randomly allocated to five dietary treatments in a completely randomized design, with six replicates of ten birds each. The control diet was maize-based, while two diets contained 10% or 20% rice bran replacing maize without XOS supplementation. Two additional diets were similarly formulated but supplemented with XOS at 250 mg/kg. All diets met established nutrient requirements, and feed and water were provided ad libitum. Data were analyzed using one-way analysis of variance, and treatment means were separated at p < 0.05. Results Birds fed the 20% rice bran diet without XOS exhibited reduced final body weight, body weight gain, and poorer feed conversion ratio compared with the control. In contrast, XOS supplementation significantly improved growth performance, with birds receiving the 10% rice bran plus XOS diet achieving the highest body weight gain and most efficient feed conversion. Inclusion of rice bran reduced feed cost per kilogram of weight gain. The lowest feed cost per kilogram of weight gain was recorded in birds fed Diet 2. XOS inclusion also improved oxidative status by lowering malondialdehyde concentration and increasing superoxide dismutase activity, while catalase and glutathione peroxidase activities were not significantly affected. High rice bran inclusion without XOS compromised intestinal morphology, as evidenced by reduced villus height, muscle thickness, and villus height-to-crypt depth ratio, particularly in the duodenum and jejunum. These adverse effects were mitigated by XOS supplementation, which enhanced gut structural development and absorptive capacity. Conclusions Supplementation of XOS at 250 mg/kg improved intestinal health, antioxidant defense, and growth performance in finisher broiler chickens fed diets containing rice bran at 10% replacement of maize, indicating its potential to enhance productivity and health. The best feed cost per kg gain was recorded at moderate dietary inclusion of rice bran without XOS.