Evaluation of critical care blood analytes assessed with a point-of-care portable blood analyzer in wild and aquarium-housed elasmobranches and the influence of phlebotomy site on results

Abstract

Objective-To establish reference ranges for critical care blood values measured in wild and aquarium-housed elasmobranchs by use of a point-of-care (POC) blood analyzer and to compare values on the basis of species category (pelagic, benthic, or intermediate) and phlebotomy site. Design-Cross-sectional study. Animals-66 wild and 89 aquarium-housed elasmobranchs (sharks and rays).Procedures-Aquarium-housed elasmobranchs were anesthetized for sample collection; wild elasmobranchs were caught via hook and line fishing, manually restrained for sample collection, and released. Blood was collected from 2 sites/fish (dorsal sinus region and tail vasculature) and analyzed with the POC analyzer. Reference values of critical care blood analytes were calculated for species most represented in each population. Values were compared on the basis of species categorization (pelagic, intermediate, or benthic) and collection site. Results-Oxygen saturation and circulating concentrations of lactate and glucose were significantly different among aquarium-housed pelagic, intermediate, and benthic species. Lactate concentration was significantly different among these categories in wild elasmo-branchs. Significant differences were detected between samples from the 2 collection sites for all blood analytes. In both study populations, pH and lactate values were infrequently < 7. 2 or > 5 mmol/L, respectively. Conclusions and Clinical Relevance-Brevity of handling or chemical restraint may have reduced secondary stress responses in fish because extreme variations in blood analyte values were infrequent. Sample collection site, species categorization, acclimation to handling, and restraint technique should be considered when assessing values obtained with the POC analyzer used in this study for blood analytes and immediate metabolic status in elasmobranchs.