Magnolol additive as a replacer of antibiotic enhances the growth performance of ducks.

Magnolol rich in is a bioactive polyphenolic compound. The aim of this study was to examine the effects of magnolol additive (MA) on growth performance, expression levels of antioxidant-related genes, and intestinal mucosal morphology of ducks aged from 49 to 70 days, comparing with that of an antibiotic additive (colistin sulfate [CS]). A total of 275, 49-day-old ducks were assigned to 5 groups with 5 cages of 11 ducks each and fed diets supplemented with 0, 100, 200 and 300 mg of MA/kg and 300 mg of CS/kg for 3 weeks, respectively. The results showed that the average daily body weight gain (ADG) was increased significantly in MA-fed groups (200 and 300 mg/kg), compared with the basal diet (BD) group ( < 0.05). The mRNA levels of superoxide dismutase-1 (), manganese superoxide dismutase-2 () and catalase () were also increased significantly in MA groups ( < 0.05). In addition, hematoxylin and eosin staining revealed that ducks fed the diets with MA had more intact intestinal mucosa than those fed the BD and CS diets. In addition, ileal villus height, ileal villus height/crypt depth ratio (V/C) and duodenal V/C were also improved significantly ( < 0.05). Taken together, these data demonstrated that MA is an effective feed additive to enhance the growth performance of the ducks by improving the antioxidant and intestinal mucosal status, suggesting that MA will be a potential additive to replace antibiotic (CS).