Hematology and serum biochemistry of free-range brown-throated sloths in two urban areas in Brazil.

Background and Aim: The brown-throated sloth (Bradypus variegatus) is widely distributed in three biomes: The Amazon, Atlantic Forest, and Caatinga. Some subpopulations are isolated in urban areas in Brazil, usually in squares and small woods. Due to the scarcity of reference values, an investigation was carried out on the hematology and blood biochemistry of brown-throated sloths from urban areas. Materials and Methods: Blood was collected by venipuncture in the femoral vein from 19 brown-throated sloths for hematological and biochemical analyses, living in two municipalities; Teofilo Otoni (TO) (Minas Gerais State) and Rio Tinto (RT) (Paraiba state), in the Atlantic Forest biome, Brazil. The samples were analyzed in specialized veterinary laboratories using automatic cell counters and slide fixation staining methods. Results: The two subpopulations of brown-throated sloths had no significant differences in most hematological values, with the exception of a higher leukocyte concentration (p<0.01) in the RT sub-population. The difference in leukocyte concentration suggests an idiosyncratic effect, as the animals were healthy and the stress of the capture was acute, not chronic. The concentrations of urea, creatinine, and alkaline phosphatase (ALP) were similar (p<0.05) in brown-throated sloths from TO and RT. Likewise, the liver enzyme concentrations (ALP, alanine transaminase [ALT], and aspartate transaminase [AST]) did not differ between the two subpopulations (p<0.05). Conclusion: Compared to another study, brown-throated sloths from TO and RT have higher plasma concentrations of ALT and ALP, suggestive of a hepatic overload. Hematological and blood biochemical findings of TO and RT can be used as clinical reference values for brown-throated sloths living in an urban environment.