<b>Parasitological and hematological analysis of Nile tilapia <em>Oreochromis niloticus</em> Linnaeus, 1757 from Guarapiranga reservoir, São Paulo State, Brazil</b> - DOI: 10.4025/actascibiolsci.v27i3.1334

Abstract

A total of 206 adult specimens of tilapia, Oreochromis niloticus, were collected from the Guarapiranga Reservoir, Sao Paulo, from August 1996 to April 1998, to relate their health condition with parasite infestation. Hematocrits and the differential leukocyte counts were analyzed. Scrapings of skin and gills were performed and this last removed and fixed for the identification of monogeneans. In the gills, Trichodina, Ichthyophtirius multifiliis, Cryptobia, amoebas and monogeneans (Cichlidogyrus sp.) were found, and in the skin, Trichodina, Cryptobia and Henneguya. The prevalence of some parasites seemed to be associated with water temperature and the level of dissolved oxygen. The hematocrit and leukocyte cells percentage showed little variation during the sampling period. Only basophils demonstrated a significant difference between monthly mean values. The eosinophil percentage was higher in fish parasitized with I. multifiliis and Cichlidogyrus sp. and in non-parasitized animals. There was no detection of fish mortality. It could be concluded that the fish were in good health even though the condition of the Reservoir water was not ideal