Objective: To establish the chronic hepatitis B duck model and study the protective effect of Millettia pulchra aqueous extract on chronic hepatitis B duck. Method: One-day old Guangxi shelducks were infected with 0.2 mL duck hepatitis B virus (DHBV). The infected ducks

detected by real-time PCR 7 days after infection

were divided into model group

M. pulchra high-dose and low-dose group (20

10 g · kg-1) and colchicine group(0.02 g · kg-1)

and the uninfected ducks were served as normal group. In addition to the normal group

the rest of ducks were vaccinated with 0.2 mL DHBV strong positive serum per week

until the end of the experiment. The corresponding drugs were successively administrated for 5 weeks after 25 weeks of DHBV attack. Blood and liver tissue were collected 24 hours after the last administration. The activity of alanine aminotransferase (ALT) and aspartate amino transferase (AST)

and the content of duck hepatitis B virus surface antigen (DHBsAg) and duck hepatitis B virus DNA(DHBV-DNA) in serum were measured. The activity of superoxide dismutase (SOD) and glutathion peroxidase (GSH-Px)

and the level of malondialdehyde (MDA) and hydroxyproline (Hyp) in liver homogenate were determined.Hematoxylin-eosin (HE) staining was used to observe the damage degree of liver cells. Result: In model group

the levels of ALT and AST

and the content of DHBsAg and DHBV-DNA in serum were significantly increased;the activity of SOD and GSH-Px was significantly decreased

and the levels of MDA and Hyp were significantly increased

compared with normal group. M. pulchra aqueous extract (20

10 g · kg-1) significantly reduced the activity of ALT

and the content of DHBV-DNA in serum

increased the activity of GSH-Px

and decreased the levels of MDA and Hyp in liver. M. pulchra aqueous extract (20 g · kg-1) significantly reduced the activity of AST

increased the activity of SOD. HE staining showed that M. pulchra aqueous extract could significantly decrease the damage degree of liver cells. Conclusion: Millettia pulchra aqueous extract has certain protective effect on chronic hepatitis B duck caused by DHBV.