Morphological, Cytochemical and Ultrastructural Studies of Blood Cells in Irrawaddy River Dolphin (Orcaella brevirostris): A Case Study

Abstract

The characteristic of erythrocytes, leukocytes and thrombocytes of a captive Irrawaddy river dolphin (Orcaella brevirostris) was described using blood sample collected from caudal vein. By morphological and ultrastructural studies, erythrocytes showed similar size as in humans and contained cytoplasmic electron dense hemoglobin without nucleus. Multilobulated granulocytes composed of cytoplasmic round-to-elongated granulecontaining neutrophils and round-to-oval shaped granule-bearing eosinophils while basophil was very scanty.
Monocytes displayed azulophilic granules and vacuolated cytoplasm with pseudopodia. Lymphocytes showed equal amounts of heterochromatin and euchromatin with numerous mitochondria in their cytoplasm. Thrombocytes, the smallest circulating blood cells, presented small pseudopodia with many cytoplasmic microtubular structures. By cytochemical staining, lymphocytes were specifically reactive to the acid phosphatase. Neutrophils, eosinophils and monocytes were positive with myeloperoxidase and Sudan black B. The advantage of this study will help standardize on the health monitoring of marine mammal species especially Irrawaddy river dolphin.