Comparison of Different Physiological Parameters for the Assessment of Hydration Status in Turtles of the Genus Trachemys

Abstract Because of their anatomical and physiological characteristics, and the limited published research on the subject, it is difficult to objectively determine the hydration status of reptiles and consequently provide appropriate fluid therapy. Various clinical and laboratory parameters have been used as indicators of chelonian hydration status, such as the presence of saliva strands or hematocrit, but their correlation with actual hydration status has not been verified. The objective of this work was to determine whether there is a significant change in various physiological parameters in Trachemys turtles exposed to a dehydration period. Fifteen Trachemys spp. turtles were studied. A physical examination was performed on day 1, including skin turgor test (SK), eyeball position (EY), tear production (Schirmer tear test [STT]), mucosal moisture (MM), cornea moisture (MC), and body weight (BW). Also, blood samples were collected to measure total solids (TS), uric acid (UA), total protein (TP), serum osmolarity (OS), and hematocrit (Hct). Water intake was completely withheld for 10 days, and sampling and physical examination were repeated. The OS, TS, TP, SK, EY, and BW differed significantly between days 1 and 10 ( P < 0.05). Using these analytes in sick and dehydrated Trachemys spp. turtles will allow development of a more precise scale for hydration status in these reptiles. By contrast, UA, Hct, STT, MM, and MC did not differ significantly between the start and end of the study, indicating that these analytes may be less reliable indicators of hydration status for these species.