Abstract: Ducks intramuscularly inoculated with avian influenza virus strains,A/duck/Guangdong/185/2004（H5N1） and A/duck/Guangdong/221/2004（H5N1）, showed that the serum alanine aminotransferase（glutamic-pyruvic transminase）, aspartate aminotransferase（glutamic-oxaloacetic transminase）, alkaline phosphatase,total protein, creatinine, cholesterol, calcium and phosphorus were significantly increased; while glucose and triglycerides were obviously decreased; albumin was decreased at first and increased later. We considered that assaying these blood biochemical indexes were useful for diagnosing avian influenza.

Key words: H5N1 subtype avian influenza; blood biochemistry; ducks