Effect of dietary mannanoligosaccharide level of performance and gross morphology of digestive tract segments of broiler chickens

The effects of different levels (0.5g/kg, l g/kg, 2g/kg and a step-down programme) of a mannanoligosaccharide product (MOS) on growth and the gross morphology of gastrointestinal tract of broilers fed a corn-wheat-soy diet were investigated in comparison to a negative control and a positive control (Zn-Bacitracin). The inclusion of MOS in broiler diets improved both weight gain and FCR in the first three weeks but only FCR in the final three weeks compared with controls. MOS did not affect growth performance in a dose-responsive manner. The average weight gain and FCR of birds fed the diet containing 2g/kg MOS group were comparable to the positive control group. MOS addition tended to affect the liver relative weight and the relative length of the small intestine.