Biochemical and hematologic values for 18 clinically healthy radiated tortoises (Geochelone radiata) on St Catherines Island, Georgia

BACKGROUND: The radiated tortoise (Geochelone radiata) is a critically endangered species in its native land, the southern portion of the island of Madagascar. Captive breeding programs have generated data on the breeding behavior and ecology of G radiata; however, hematologic and biochemical data also are critically important in managing populations. OBJECTIVE: The purpose of this study was to evaluate sex and seasonal effects on hematologic and biochemical data from captive radiated tortoises. METHODS: Whole blood was collected in January and August 2001 from 18 radiated tortoises (10 male, 8 female) housed at the Wildlife Survival Center on St Catherines Island, Georgia, as part of a routine health assessment. Routine hematologic and plasma biochemical analyses and electrophoresis were done using standard methods. Data from male and female tortoises were compared within and between seasons using 2-way ANOVA. RESULTS: RBC and HCT values were significantly higher in summer than in winter and were higher in males than in females. Total protein concentration did not differ significantly between males and females; however, female tortoises had significantly higher concentrations of alpha1- and beta-globulins in winter and summer compared to males. Male tortoises had significantly higher sodium and uric acid concentrations and LDH activity during winter, and higher urea concentration and LDH and CK activities in summer, compared with females. Female tortoises had significantly higher triglyceride and phosphorus concentrations in winter, and higher phosphorus, cholesterol, and triglyceride concentrations in summer, compared with males. CONCLUSION: Sex and seasonal differences in hematologic and biochemical values for radiated tortoises likely reflect vitellogenesis and egg production in females, and altered hydration status and activity in summer. Data from the tortoises in this study will be useful for the seasonal health assessment of this species.