Hematologic and biochemical reference intervals for captive Tsushima leopard cats (Prionailurus bengalensis euptilurus): Effects of origin, sex, age, and anesthesia

Abstract

The Tsushima leopard cat (Prionailurus bengalensis euptilurus) is an endangered felid endemic to Tsushima Island, for which conservation breeding programs have been established. However, the lack of species-specific clinicopathological reference intervals (RIs) limits accurate clinical assessment, which is essential for effective conservation and management. This study aimed to establish hematologic and biochemical RIs for captive Tsushima leopard cats and evaluate the effects of origin, sex, age class, and anesthetic exposure on these parameters. RIs and 90% confidence intervals were estimated using a nonparametric bootstrap percentile method for captive, non-anesthetized animals (48 animals; 204 samples). Evaluation of domestic cat RI transferability revealed that domestic cat RIs did not apply to 61.8% of analytes, indicating that these intervals should not be used for this subspecies. Analysis of indices of individuality confirmed the clinical utility of population-based RIs for many analytes. Comparisons between captive and free-ranging animals revealed significant differences in erythrocyte-related parameters and in alanine aminotransferase, total bilirubin, blood urea nitrogen (BUN), phosphorus, and total cholesterol, which may reflect differences in nutritional status, parasite exposure, and diet. Additionally, higher WBC, glucose (GLU), and creatine kinase were observed in free-ranging animals, consistent with capture-related stress responses. No significant sex-related differences were detected. Age-related differences were observed in a subset of variables, including lower erythrocyte-related parameters and higher BUN and creatinine concentrations in senior animals. Anesthetic exposure significantly affected several variables: isoflurane anesthesia was associated with reductions in erythrocyte-related parameters, whereas medetomidine–ketamine anesthesia was associated with increased GLU concentrations. This study provides the first statistically derived, subspecies-specific clinicopathological RIs for the Tsushima leopard cat and, to our knowledge, also represents the first formal set of RIs for leopard cats (Prionailurus bengalensis). These results provide a basis for improved clinical interpretation, longitudinal health monitoring, and conservation management of this endangered species.