HEMATOLOGY OF THE LOGGERHEAD TURTLE, CARETTA CARETTA

The study of the hematological characteristics of loggerhead turtles can be very helpful in the rescue and rehabilitation of this endangered species. Normal hemocellular and biochemical values are the basis for the evaluation of a subject’s health status. The identification of the blood cells through cytochemical or immunocytochemical methods is the first step to obtain a correct classification of the cells. The following blood cell types were found: lymphocytes, monocytes, heterophils (the counterparts of mammalian neutrophils), eosinophils, basophils (rarely observed), erythrocytes along with some of their precursors, and thrombocytes. Lymphocytes and monocytes are easily distinguishable, as they are similar to the mammalian counterparts, whereas heterophils (which are the equivalent of mammalian neutrophils) and eosinophils both contain eosinophilic granules in their cytoplasm, making their identification difficult. The thrombocytes are nucleated cells, whose shape is variable in dry film smears of circulating blood, either round or oval; they take part in the hemostatic process, as suggested by their tendency to form aggregates. The erythrocytes are also nucleated cells, showing an ellipsoidal and flattened configuration. In all specimens of this marine reptile, both healthy and unhealthy, the mature erythrocytes contain one characteristic inclusion in their cytoplasm, which was recognized as a Heinz body, formed by the precipitation of hemoglobin. The loggerhead's hemoglobin was studied in depth and revealed some specific characteristics, one of which is that under physiologic conditions it precipitates due to its instability. While no data are available about the erythropoiesis in the primary organs, circulating erythropoiesis was revealed to occur in the loggerhead's blood, just as it also occurs at this site in other non-mammalian vertebrates