Metabolic profiles were monitored in 24 Muscovy duck males and 24 Common females at 35 days and at the characteristics slaughtering age for each species (57 days and 78 days for common duck and muscovy duck, respsctively) Both species of ducks were differently fed (diet C: a commercial diet, maize-soya based;diet A: maize replaced by low tannin sorghum; diet B: maize replaced by a mixture of low and high tannin sorghum, (50% +50%) Results showed thar glucose, tryglicerides and albumine were higher while total proteins were lower in common ducks fed the diets containing sorghum. Glucose level, cholesterol and free fatty acids were lower in muscovy ducks fed the diets containing sorghum. The different trend observed confirms the big dofferences between the digestive ability of muscovy and common ducks.