Hematological and phagocytic response of the fat snook, Centropomus parallelus, reared in net cages, before and after inoculation with Sacharomyces ceresivisiae

The aim of this study was to examine the blood and the macrophagocytic response of fat snook of Centropomus parallelus before and after injection with Saccharomyces cerevisiae. Ten adults were used, caught using net cages in the lagoon-estuarine region of Cananeia (SP), Brazil. The fi sh were anesthetized and blood was drawn followed by inoculation with yeast. After 8 hours, the fi sh were again removed from the cages and anesthetized. A new sample of blood was collected and the animals were then sacrifi ced by deep sedation. The blood was used for the determination: erythrocyte count, hemoglobin concentration and hematocrit, calculation of Mean Corpuscular Volume and Mean Corpuscular Hemoglobin Concentration, and preparation of smears, utilized for total and diff erential leukocyte counts white blood cells and thrombocyte count. There was a signifi cant decrease in almost all parameters 8hrs after inoculation (p0.05), with exception of mean corpuscular volume which showed a signifi cant increase (p>0.05). Leukopenia, lymphopenia, neutropenia and monocytosis occurred when comparing the values of the fi rst and second samples, in both inoculated and non inoculated fi sh. With the white blood cells, lymphocytes and neutrophils, values were signifi cantly higher in the inoculated fi sh versus those which were not inoculated, in both blood samplings. The number of thrombocytes was higher in inoculated than non inoculated individuals, but 8 hours after inoculation the values in the two groups were similar. The phagocytic capacity and index were: mean=56.0 and standard deviation=8.8% and mean= 1.8 standard deviation=0.3, respectively. In conclusion, it was verifi ed that the repeated sampling of blood induces alterations that are harm to the welfare of the animals. Key words : Phagocytosis. Hematology. Macrophage migration. Fat snook.