Effect of Ammonia on Antioxidant Responses in Serum of Yellow River Carps

To study the toxic effects of ammonia on the aquatic species,juveniles of Yellow River carp were assigned to 4 groups with an ammonia nitrogen concentration of 0(control),0.071,0.143 and 0.284 mg/L respectively.Samples were taken on 7,14,28 and 35 days after the start of the treatments and SOD and GSH-Px activities and MDA content of the serum were determined.The results demonstrated that with increasing ammonia concentration,the activity of SOD in the serum first increased and then decreased,while the activity of GSH-Px and content of MDA showed a rising trend.Variance analysis indicated that ammonia exposure had a highly significant influence on the content of MDA(p0.01).With the extension of ammonia exposure time,the activity of SOD declined and the content of MDA exhibited a rising trend.Variance analysis showed no significant difference(p0.05).Within the concentration range of the test,ammonia reduced the oxidation resistance of carp,and MDA content could be used as an effective biomarker for toxicity assessment of ammonia in Yellow River carps.