Haematology, cytochemical and ultrastructural characteristics of blood cells in leopard (Panthera pardus)

The leopard (Panthera pandus) is an endangered Asian big cat found in Thailand and also listed in the CITES, Appendix 1. Blood samples from 17 leopards (six males and 11 females) were collected from the cephalic vein for haematology, cytochemical and ultrastructural studies. Red blood cells (RBCs) were slightly anisocytosis, ranged 5–6.5 μm with 5.6 μm mean diameter. They were easy to form rouleaux, blunt end crenation and some RBCs contained Heinz bodies. The male leopards had a significantly higher packed cell volume (39.3 ± 7.5%) values and absolute eosinophil number (1.658 ± 1.483 × 10⁹/l) than the females (30.7 ± 3.2%; 0.965 ± 0.611 × 10⁹/l). The cytochemical results were: sudanophilia and myeloperoxidase in neutrophils and some monocytes; nonspecific esterase (alpha-naphthyl acetate esterase, ANAE) in the granules of eosinophils, some lymphocytes, some monocytes and platelets; beta-glucuronidase (βG) in granules of basophils, monocytes and some lymphocytes. The ANAE and βG reaction were detected inter-granular of eosinophils. More detailed morphological aspects of all blood cells were observed by means of scanning electron microscope and transmission electron microscope (TEM). The many round granules and homogeneous content under TEM were characteristics of leopard eosinophils. The engulfed RBCs by neutrophils were detected under TEM in one male leopard. This study provides a guide for the haematology, identification of the morphology, cytochemistry and ultrastructure of blood cells in leopards that is useful for zoological veterinarians in leopard conservation.