Cytomorphology and Seasonal Hematological Parameters in Tegu Lizards (Salvator merianae) Raised in Captivity

Abstract

Aims: In this study, we describe cytomorphology and haematological values in Salvator merianae lizards bred in captivity, in order to establish reference values for health monitoring by veterinarians in animal production. Study Design: Blood samples obtained from the tail vein of adult specimens at different times of the seasonal cycle were analysed. Cell morphology was characterised by light and electron microscopy and the corresponding blood counts were performed. Seasonal changes and annual averages of hematocrit, haemoglobin, erythrocytes, leukocytes, platelets and percentage leukocyte formula were determined. In addition the blood was analysed by flow cytometry. Place and Duration of Study: The study was conducted in El Manantial, Tucumán, Argentina with Salvatormerianae lizards, raised at the experimental farm of the Facultad de Agronomía y Zootecnia of the Universidad Nacional de Tucumán between 2014 and 2017. Methodology: Routine methods of haematology adapted to nucleated erythrocytes were used for this study. Five males and five females individually identified were sampled throughout the annual cycle. Results: Light microscopy showed 7 cell types: erythrocytes, neutrophils, azurophils, basophils, monocytes, lymphocytes and thrombocytes. Flow cytometry was used because it allows an accurate count of the number of white blood cells; an average of 7.2 x103/µl was obtained. Changes related to seasonality were observed in the hematocrit and haemoglobin. Significant differences in the annual average hematocrit and haemoglobin between the sexes were found with 42.5 ± 0.61% for males and 40.1 ± 0.60% for females. No seasonal changes in the values of leukocytes or the leukocyte differential count were found. Conclusion: This study provides haematological reference values necessary for an adequate sanitary evaluation of farm-raised S. merianae.