Haematological, cytochemical and ultrastructural characteristics of blood cells and serum chemistry in captive Malayan tapir (Tapirus indicus) in Thailand

Abstract

The Malayan tapir (Tapirus indicus) is classified as a preserved animal of Thailand. It is listed as an endangered species on the 2008 IUCN red list and also by the Convention on International Trade in Endangered Species of Wild Fauna and Flora. Blood samples from captive Malayan tapirs (n = 20, 10 males and 10 females) from five zoos under the Zoological Park Organization of Thailand were examined and measured for complete blood counts, serum chemistry and electrolyte analysis. Cytochemical staining including Peroxidase, Sudan Black B, Periodic acid Schiff's reaction (PAS), α-naphthyl acetate esterase (ANAE) and β-glucuronidase (BG) was also analysed. Statistically significant differences were found between sexes including alkaline phosphatase, total protein and red cell distribution widths. Red blood cells were slightly anisocytosis, (range 4.5–8.5 μm) with 6.3-μm mean diameter. Eosinophils and monocytes were positive with all five cytochemical stains. Lymphocytes showed a variable reaction for ANAE and BG. PAS was positive for all type of blood cells except red blood cells. Ultrastructurally, eosinophils had the largest round shape with three-capsule layer granules which were prominent and distinguishable from other species. This investigation provides basic haematology and serum chemistry analyses as well blood cells identification guideline for the Malayan tapir and serves as endangered mammal reference values.