Fecal Glucocorticoid Metabolites as a Noninvasive Indicator of Stress in the Tsushima Leopard Cats (Prionailurus bengalensis euptilurus): Application to Health Care

Abstract

This study investigates whether the measurement of glucocorticoid metabolites (GCMs) in feces is a useful method for the noninvasive evaluation of stress in the endangered Tsushima leopard cats (Prionailurus bengalensis euptilurus). Feces were collected from six seemingly healthy and five diseased (renal dysfunction, adrenal tumor, hernia, feline immunodeficiency virus (FIV), feline leukemia virus (FeLV)) Tsushima leopard cats in captivity. Fecal GCMs were measured by enzyme immunoassay (EIA) for cortisol. Individuals that experienced a physical examination under anesthesia showed increased fecal GCMs 1-2 days after the event. An individual diagnosed with disk herniation showed decreased fecal GCMs after medical administration. The mean fecal GCM concentrations for six healthy animals and five diseased animals were 0.66 ± 0.08 and 2.65 ± 0.76 μg/g, respectively, which was significantly different. Cortisol and corticosterone were not clearly detected in the feces examined by the use of the HPLC-EIA analysis. GCMs may be excreted in the feces; however, the exact identification of these substances is not achieved. The results suggest that the measurement of fecal GCMs is useful for the husbandry and health management of this species.

Keywords: carnivore; cortisol; fecal hormone; glucocorticoid; leopard cat; stress.

Figure 1

Changes in fecal glucocorticoid metabolite concentrations in 6 Tsushima leopard cats (No.16, No.23, No.28, No.53, No.54, and No.60) measured around the day of physical examination. All cats had their health condition examined under anesthesia. No.52 and No.54−1 were excluded from the figure because feces could not be collected for 4 and 6 days after treatment, respectively.

Figure 2

Changes in fecal glucocorticoid metabolite concentrations since the day of dexamethasone administration in a Tsushima leopard cat No.52 diagnosed with disc herniation. For medical treatment, intramuscular injection of dexamethasone and oral administration of prednisolone were administered as anti-inflammatory agents. The prednisolone was intermittently administered during the study period. * Significant difference (p < 0.05).

Figure 3

Average concentrations of fecal glucocorticoid metabolites for 6 healthy (No.16, No.18, No.28, No.42, No.43, and No.60) and 5 diseased (No.17, No.23, No.52, No.53, and No.54) Tsushima leopard cats. No17 and No.23: renal dysfunction; No.52: FIV and hernia; No.53: FIV and adrenal tumor; No.54: FeLV. Numbers in parentheses indicate the number of fecal samples analyzed. To avoid the effects of temporary stress, data from the day of anesthesia to the 4th day were excluded from each mean for the examined animals. * The diseased animals showed significantly higher values compared to the healthy animals (p < 0.05).

Figure 4

The immunoreactive cortisol and corticosterone in HPLC fractions of (a) reference tracers and (b) fecal extract from cat No.52. Top of the figure shows the immunoreactive peaks measured from the mixture of reference tracers by using cortisol and corticosterone antibodies. Bottom of the figure shows HPLC separation of immunoreactive glucocorticoid metabolites from feces. The arrows show the elution positions of the reference tracers for cortisol and corticosterone.