Blood Chemistry of Antillean Manatees (Trichechus manatus manatus): Age Variations

The Antillean manatee (Trichechus manatus manatus) is the most endangered aquatic mammal in Brazil. Sampling blood data from such critically endangered marine mammal species is extremely challenging. Although several hematological studies have been developed for captive manatees, captivity studies addressing the environmental and physiological effects on blood values are scarce. The present work describes blood biochemistry values for captive Antillean manatee adults and calves and verifies the occurrence of possible physiological adjustments due to age, sex, and dietary influences. Blood from 13 clinically healthy manatees (eight calves and five adults) were analyzed for 13 blood serum chemistry parameters using a semi-automatic analyzer. Descriptive analysis was performed for all parameters, and differences between sex and age were determined. Calves had higher means of urea (6.29 ± 5.58 mg/dL), total proteins (5.07 ± 0.94 g/dL), globulin (3.06 ± 1.32 g/dL), and alanine aminotransferase (6.19 ± 2.18 U/mL), levels, and lower means of creatinine (1.42 ± 0.64 mg/dL), aspartate aminotransferase (7.24 ± 3.21 U/mL), phosphate (3.03 ± 1.63 mg/dL), and uric acid (0.71 ± 0.17 g/dL) than adults. Further studies are necessary, especially when considering handling and alimentary management in captivity, to provide important data for better monitoring and clinical management of manatees.