OF THE TROPICAL FISH PROCHILODUS SCROFA TO ACUTE COPPER EXPOSURE AND SUBSEQUENT RECOVERY

Changes in Prochilodus scrofa blood cells were investigated after 96-h of exposure to copper and following transference to clean water. Hematocrit, red blood cells and hemoglobin concentrations showed a significant increase after copper exposure, remaining high until the 7th day after transference to clean water. The immature blood cells (erythroblasts) also increased significantly, but did not differ from the controls on the 7th day in clean water. The changes in leukocytes occurred only in the percentage of lymphocytes, which was significantly reduced after 96-h copper exposure, remaining lower on the first and second day in copper-free water. Thrombocytes increased significantly in fish exposed to copper and remained high on the 7th day in clean water. The changes in the blood cells of P. scrofa reflect the animals ’ responses to stress caused by copper; however, after their transfer to clean water, most of the changes involved a compensatory physiological mechanism that allowed the fish to recover from copper-related damage