Objective  Expressions of Cu/Zn-SOD gene and activities of the antioxidant enzyme in various organs of mule ducks were determined.

  Method  The gene expression in the heart, liver, spleen, lung, kidney, gizzard and chest muscles, antioxidant enzyme activities, and MDA contents of mule duck were determined by the qRT-PCR, xanthine-xanthine oxidase, and thiobarbituric acid methods.

  Result  The greatest mRNA expression of Cu/Zn-SOD gene was found in the chest muscle followed by the tissues in the order of liver > lung > heart > spleen > gizzard/kidney of the ducks. The activities of Cu/Zn-SOD enzyme in the liver and kidney were significantly higher than those in the breasts and gizzard. The higher MDA content in the breasts than in the liver, gizzard or kidney indicated a greater susceptibility of the chest muscle to damage by oxidative stress. There was no significant correlation observed between the antioxidant enzyme activity and the mRNA expression level in different organs. However, the Cu/Zn-SOD enzyme activity was inversely correlated to MDA content in the tissues.

  Conclusion  The Cu/Zn-SOD mRNA expression and enzyme activity were organ-specific. The differences in the enzymatic activities might stem from the diverse physiological functions of the enzymes and/or the tissue metabolism per se.