Magnolol Additive Improves Growth Performance of Linwu Ducklings by Modulating Antioxidative Status

Magnolol is a bioactive polyphenolic compound commonly found inMagnolia officinalis. The aim of this study is to clarify the contribution of the magnolol additive on the growth performance ofLinwuducklings aging from 7 to 28 d, comparing to the effects of antibiotic additive (colistin sulphate). A total of 325, 7-d-old ducklings were assigned to 5 groups. Each group had 5 cages with 13 ducklings in each cage. The ducklings in different groups were fed with diets supplemented with 0, 100, 200 and 300 mg/kg magnolol additive (MA) (Control, MA100, MA200 and MA300) and 30 mg/kg colistin sulphate (CS30) for 3 weeks, respectively. Parameters regarding to the growth performance, intestinal mucosal morphology, serum biochemical indices, antioxidant and peroxide biomarkers and the expression levels of antioxidant-related genes were evaluated by one way ANOVA analysis. The results showed that 30 mg/kg colistin sulphate, 200 and 300 mg/kg magnolol additive improved the average final weight (P= 0.045), average daily body weight gain (P= 0.038) and feed/gain ratios (P= 0.001) compared to the control group. 200 and 300 mg/kg magnolol additive significantly increased the villus height/crypt depth ratio of ileum, compared to the control and CS30 groups (P= 0.001). Increased serum level of glucose (P= 0.011) and total protein (P= 0.006) were found in MA200 or MA300 group. In addition, comparing to the control and CS30 groups, MA200 or MA300 significantly increased the levels of superoxide dismutase (P= 0.038), glutathione peroxidase (P= 0.048) and reduced glutathione (P= 0.039) in serum. Moreover, the serum and hepatic levels of 8-hydroxy-2’-deoxyguanosine (P= 0.043 and 0.007, respectively) were lower in all MA groups compared to those of the control and CS30 group. The hepatic mRNA expression levels ofsuperoxide dismutase-1,catalaseandnuclear factor erythroid-2-related factor 2/erythroid-derived CNC-homology factorwere also increased significantly in MA200 and MA300 groups (P< 0.05). Taken together, these data demonstrated that MA was an effective feed additive enhancing the growth performance ofLinwuducklings at 7 to 28 d by improving the antioxidant and intestinal mucosal status. It suggested that MA could be a potential ingredient to replace the colistin sulphate in diets.