Comparative study of biochemical, histological and molecular biomarkers of heavy metal contamination in Cyprinus carpio collected from warm-monomictic lake and government culture pond

The study investigated the metallothionein (MT) and glutathione peroxidase (GPX) genes expression in freshwater fish Cyprinus carpio dwelling in Warm-monomictic Lake (Dal) and Government culture pond. Oxidative stress induced by heavy metals in the fish body manipulates stress genes expression resulting in the production of scavenger protein (for free metal ions) metallothionein. It interacts with Cu, Cr, Ni and Cd via metal-thiolate bond relieving the metal load from fish body. Maximum fold change was observed in liver, muscle and midgut tissue. Similar rise seen in GPX indicates defence against lipid peroxidation. MT and GPX genes data were compared with beta-actin gene used as an internal control. Limnological studies of both the sites (temperature, dissolved oxygen, pH, total dissolved solids, conductivity), were essential to ensure the quality of water in which the dominant species (C. carpio) was thriving, as these fishes are transported for human consumption. Heavy metal concentration (water, tissues, gut content), bioindices, biochemical parameters and histological alterations were studied to observe the impact of elements selected.