Abstract
Cyprinus carpio were exposed under field conditions to 20.87 µg l^−1^ of commercial herbicide bispyribac‐sodium (Nominee®, SC), during 7, 21 and 72 days. Enzymatic parameters such as catalase (CAT), glutathione S‐transferase (GST) and acetylcholinesterase (AChE) activities, as well as thiobarbituric acid‐reactive substances (TBARS) and protein carbonyl contents were studied in different tissues. After 7 days of exposure, GST activity decreased. At the same period, brain AChE activity increased, but a reduction of activity was observed in muscle tissue. Brain TBARS levels increased at 7 days. After 21 days of exposure liver CAT levels and muscle AChE activities decreased. In the same period, liver protein carbonyl and muscle TBARS increased. After 72 days of exposure in the field, AChE activity was reduced in both brain and muscle. Protein carbonyl contents in liver and brain TBARS levels increased. Muscle AChE activity, TBARS and protein carbonyl can be used as biomarkers of exposure to the herbicide bispyribac‐sodium. This study demonstrates effects of exposure to bispyribac‐sodium under rice field conditions on oxidative stress parameters in tissues of Cyprinus carpio. Copyright © 2010 John Wiley & Sons, Ltd.