Hematological characteristics of the spotted rose snapper Lutjanus guttatus (Steindachner, 1869) healthy and naturally infected by dactylogyrid monogeneans

The aim of the present study was to obtain a basic knowledge of the hematology in order to determine changes in blood parameters of the spotted rose snapper Lutjanus guttatus. The morphological features of blood cells were described according to the observations made by light microscopy of Wright–Giemsa-stained blood films. The reference intervals and the mean value were determined for each hematological parameter evaluated in healthy fish and data were compared to those of naturally infected, with dactylogyrid monogeneans fish.Infected fish showed a prevalence of 100% and a mean intensity of 246.6 parasites per fish. Mean values of HCT, WBC, thrombocytes percentage and eosinophils percentage were significantly higher (P < 0.05) in the infected fish. In addition, lymphocytes percentage and total protein were significantly lower (P < 0.05) in the infected fish compared to healthy fish. Only total WBC count, lymphocytes percentage and eosinophils percentage in infected fish were outside reference interval. The hematology of the spotted rose snapper of this study might serve as a basis for future studies and diagnosis. Changes observed in blood parameters in infected fish suggest that the immune system of L. guttatus was affected by the presence of the parasites.