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

Abstract

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; Teófilo Otoni (TO) (Minas Gerais State) and Rio Tinto (RT) (Paraíba 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.

Hematologic and biochemical reference intervals of brown‐throated sloths (Bradypus variegatus)

“…This is the first study that provides population‐based RI for Bradypus variegatus . There are only a few reports of hematologic and plasma biochemical values in B. variegatus , 11,14‐16 all had smaller sample sizes (10–19 individuals) than in the present study. Importantly, none of these prior studies calculated population‐based RIs using statistical analysis.…”

“…biochemical values in B. variegatus,11,[14][15][16] all had smaller sample sizes(10-19 individuals) than in the present study. Importantly, none of these prior studies calculated population-based RIs using statistical analysis.…”

“…A direct comparison of the descriptive values presented here with previously reported numbers is challenging. There are many differences between our study and previous reports: (i) the number of individuals is often smaller; (ii) the geographic origin of the samples is different with distinct biotic and abiotic factors (ie, captivity animals); 11,[14][15][16] (iii) sample collection conditions differ (ie, anesthesia); 11 and finally, (iv) some of the samples were either analyzed by distinct processes, 15 or did not describe the methodology used. 14 With so many confounding factors and smaller sample sizes, it is impossible to disambiguate real population differences from methodologic and geographic differences.…”

“…Nevertheless, in the daily routine of the veterinary laboratories, several tests are adapted from human diagnostics, and it is challenging to know if the same methods have the same performance for all animal species. Another issue is that in the majority of available studies that propose to establish RIs in animals do not describe the method used for biochemical analysis, which is the case for B. variegatus 16 . It is worth mentioning that the methods used in the present study have not been specifically validated in B. variegatus but have been used previously, and similar species and are expected to perform adequately.…”

“…Another issue is that in the majority of available studies that propose to establish RIs in animals do not describe the method used for biochemical analysis, which is the case for B. variegatus. 16 It is worth mentioning that the methods used in the present study have not been specifically validated in B. variegatus but have been used previously, and similar species and are expected to perform adequately. Further studies addressing the comparison of different laboratory diagnostic methods for biochemical analysis are encouraged.…”