Serum biochemistry of the Arrau turtle (Podocnemis expansa): Frozen analyte stability and the effects of long-term storage.

Abstract

Turtles are a major source ofprotein for riverside human populations in Brazil. The encouragement of commercial breeding meets conservation effortsfor these animals, andit is, therefore, crucial to understandthe physiologic and behavioral aspects of semi-aquatic species in captive conditions. Serum biochemical tests are ancillary diagnostic tools, and samplestorage isamain problem since clinical laboratoriesare not always available near the habitats ofthese species. The aim of this study was to provide information about the stability of albumin, aspartate aminotransferase (AST), calcium, creatinine kinase (CK), total cholesterol (Chol),alkaline phosphatase (ALP), gamma glutamyltransferase (GGT), total protein (TP), and urea at different storage times. In all, 17 Arrau turtles (Podocnemis expansa) were used, and the serum obtained was separated into aliquots and analyzed at 0, 4, 8, 16, and 32days after being stored at-20°C. The results showedthat albumin, AST, CK, GGT, and TP suffered interference due to the long storage times. Analytes such as ALP, calcium, Chol, and urea can be evaluated for up to 1month after freezing. Albumin, AST, and TP can be analyzed up to 1week after freezing without alterations, and CK GGT are best evaluated on fresh samples.