Metal effects on histological and biochemical parameters of common rudd (Scardinius erythrophthalmus L.)
Elenka Georgieva, Stela Stoyanova, Iliana Velcheva, Tonka Vasileva, Veselin Bivolarski, Ilia Iliev, Vesela Yancheva
ABSTRACT. The present study aimed to evaluate the current contamination status of Topolnitsa Reservoir, which is located in a region with intensive copper mining. The reservoir has been continually contaminated with metals over the last few decades. As, Cd, Cu, Ni, Pb, and Zn concentrations were measured in surface water samples and in the liver of common rudd, Scardinius erythrophthalmus (L.), in three different seasons: spring, summer, and autumn. The morphological structure of the fish liver was examined and the hepatic LDH, ALAT, and ASAT activities were measured. In general, metal concentrations in the water varied, but As and Cu were present in all three seasons at levels higher than the maximum permissible levels set by law. The metal concentrations in the fish liver were significantly higher than in the water. Histological alterations were classified as degenerative changes (granular, vacuolar, hydropic, and fatty degeneration), necrotic changes (necrobiosis) – karyopyknosis, karryorehsis, and karyolyzis, and necrosis)); and changes in blood vessels (hyperemia in sinusoids and major blood vessels). Higher LDH, ALAT, and ASAT activities in fish livers were measured in comparison to reference fish. In addition, the ALAT activity in the livers of S. erythrophthalmus from Topolnitsa Reservoir was significantly higher in the summer. Overall, it can be concluded that the metal-contaminated waters of Topolnitsa Reservoir lead to negative changes in the common rudd tissues at the cellular level including impaired structure and enhanced enzymatic activity in the fish liver.
Keywords: metals, fish, liver, histology, enzymes
CORRESPONDING AUTHOR:
E. Georgieva
Department of Developmental Biology, Faculty of Biology, Plovdiv University, Bulgaria
S. Stoyanova [+], I. Velcheva, V. Yancheva
Department of Ecology and Conservation of Nature
Faculty of Biology, Plovdiv University, Bulgaria
24, Tzar Asen, St., 4000, Plovdiv, Bulgaria
Tel.: +35932261513; e-mail: stela.st@abv.bg
T. Vasileva, V. Bivolarski, I. Iliev
Department of Biochemistry and Microbiology, Faculty of Biology, Plovdiv University, Bulgaria