Effects of exposure to sublethal propiconazole on intestine-related biochemical responses in rainbow trout, Oncorhynchus mykiss

The effect of long-term (30 days) exposure to PCZ (0.2, 50, and 500 mu g l(-1)) on intestine-related biochemical markers in rainbow trout was investigated. Multiple biomarkers were measured, including digestive enzymes (proteolytic enzymes and amylase), antioxidant responses (TBARS, CP, SOD, CAT, GR and GPx) and energy metabolic parameters (RNA/DNA ratio, Na+-K+-ATPase). Exposure to 500 mu g l(-1) PCZ led to significantly inhibited (p<0.01) proteolytic enzyme and amylase activity. Activities of the antioxidant enzymes SOD, CAT, and GPx gradually increased at lower PCZ concentrations (0.2 and 50 mu g l(-1)). At the highest concentration (500 mu g l(-1)), oxidative stress was apparent as significant higher (p<0.05) lipid peroxidation and protein carbonyls, associated with an inhibition of antioxidant enzymes activity. Moreover, energy metabolic parameters (RNA/DNA ratio, Na+-K+-ATPase) were significantly inhibited (p<0.01) in the intestines of fish exposed to 500 mu g l(-1) PCZ, compared with controls. We suggest that long-term exposure to PCZ could result in several responses in intestine-related biochemical markers, which potentially could be used as indicators for monitoring residual PCZ present in the aquatic environment. Crown Copyright (C) 2010 Published by Elsevier Ireland Ltd. All rights reserved.