A morpho-histopathological study in the digestive tract of three fish species influenced with heavy metal pollution.

In this study, the digestive tract of three freshwater fish species (Capoeta capoeta, Alburnus mossulensis and Squalius cephalus) was examined using a morpo-histopathological technique. Sediment and fish samples were taken from selected four stations in the Karasu River (Erzurum, Turkey) between June and September in 2015-2016. In water and sediment samples, the concentrations of some metals (Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Sr and Pb) were determined. Histopathological changes in digestive tract were determined by histopathological alterations index (HAI). Intestinal coefficient (IC) and condition factor (CF), which are general indicators of exposure to environmental stress, were calculated for each fish. The highest CF was observed at the least contaminated site of the gradient. C. capoeta showed the highest values of IC among species. The detected abnormalities were infiltration, swelling, gastric degenerations, vacuolization, congestion, epithelial degenerations, hyperplasia, fibrosis and fusion at polluted site fish. It was also observed that the HAI and IC values in fish varied significantly from site to site. The results showed that the content of heavy metals in the river water and sediment may affect the health status of the fish species.