HEMOPARASITES OF RED PIRANHA Pygocentrus nattereri (KNER, 1858) (CHARACIFORMES: CHARACIDAE) CAPTURED IN RED RIVER, MIDDLE ARAGUAIA RIVER REGION, STATE OF GOIÁS (GO), BRAZIL

Abstract

This work aimed to evaluate blood smears of 128 red piranha specimens Pygocentrus nattereri (Kner, 1858) (Characiformes: Characidae) as for the presence of hemoparasites and blood cells that were visualized. Samples were collected in Rio Vermelho (Red River) (15°10'44.73''S and 51°09'55.83W''), in the Brazilian state of Goiás, between April 2012 and August 2013, including ebb, full and dry phases. After identificating and numbering the piranhas, we collected approximately 0.5 mL of blood from each animal, from the caudal vein or through intracardiac puncture, and two blood smears were done and stained with May Grünwald-Giemsa and Fast Panoptic stains. After euthanasia, the body mass and biometrics of every fish were measured. Abiotic factors of the river water were also analyzed, such as temperature and transparency. In general, the biometric parameters were higher in the full phase of the river, and the values obtained on water quality were similar in relation to the average temperature of the water, which was around 82,4°F. The average transparency of the water varied, being greater at low tide. Erythrocytes, thrombocytes, neutrophils, eosinophils, monocytes, heterophile and lymphocytes were identified as blood cells of red piranhas and hemogregarines have been found in about 25% (32/128) of the blood smears.