Chronic exposure to pollutants in Madin Reservoir (Mexico) alters oxidative stress status and flesh quality in the common carp Cyprinus carpio

Madin Reservoir (MR) is located on the Rio Tlalnepantla in Mexico. Previous studies seeking to identify pollutants at this site evidence that MR water contains a considerable metal load as well as nonsteroidal anti-inflammatory drugs (NSAIDs) at concentrations above those determined suitable for aquatic life. This study aimed to evaluate whether chronic exposure to pollutants in MR alters oxidative stress status and flesh quality in muscle of the common carp Cyprinus carpio. The following biomarkers were evaluated in muscle of carp caught in the general area of discharge from the town of Viejo Madin: hydroperoxide content (HPC), lipid peroxidation (LPX), protein carbonyl content (PCC), and activity of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). Physicochemical and textural properties of muscle were also evaluated. Results show that the metals Al and Fe were accumulated in muscle of C. carpio at levels of 21.3 and 29.6 mu g L-1, respectively, and the NSAIDs diclofenac, ibuprofen, and naproxen at levels from 0.08 to 0.21 ng L-1. Fish exposed to discharge from the town of Viejo Madin showed significant increases in HPC (9.77 %), LPX (69.33 %), and PCC (220 %) with respect to control specimens (p < 0.05). Similarly, enzyme activity increased significantly: SOD (80.82 %), CAT (98.03 %), and GPx (49.76 %). In muscle, physicochemical properties evidenced mainly significant reductions compared to control values while textural properties showed significant increases. Thus, water in this reservoir is contaminated with xenobiotics that alter some biological functions in C. carpio, a fish species consumed by the local human population.