A field‐friendly method of measuring faecal glucocorticoid metabolite concentration as a simple stress checker in snow leopards. Issue 9 (6th July 2021) - Kinoshita, Kodzue
Abstract: The hormonal analysis of excrement has been employed to non‐invasively assess the physiological conditions of domestic, experimental, zoo and wild animals to. However, conventional hormone analysis techniques require frozen and refrigerated reagents, and laboratory equipment; therefore, it is almost impossible to obtain the results on‐site. This study attempted to establish a method for the simple and rapid quantitative on‐site analysis of faecal glucocorticoid metabolite (fGM) concentrations; this method involved using hand‐shaking for faecal hormone extraction, and immunochromatography using test strips and a smartphone application. This study focused specifically on snow leopards and developed a new, simple fGM measurement method to evaluate their stress levels on‐site. First, the effects of ultraviolet exposure and bacterial activity on fGM concentration, including sample age, were evaluated using faeces from a captive snow leopard. Second, a field‐friendly hormone extraction method was evaluated; this method does not require storage of faeces in the field because the hormones are extracted by hand‐shaking of faeces in ethanol at the time of collection. In addition, to measure hormone concentrations on‐site, a simple immunochromatography measurement kit was used. The concentrations were measured by quantifying the colour reactions using a smartphone application. There was no consistent increase or decrease in fGM concentration with ultraviolet irradiation time. In addition, a high correlation was observed between concentrations extracted using the conventional method (using a vortex mixer and methanol extraction) and those from the field‐friendly method ( r = 0.812, p < 0.05). Changes in fGM concentration measured using immunochromatography were also highly consistent with those measured using the conventional method (enzyme immunoassay; r = 0.825, p < 0.05). The analytical validation of immunochromatography also showed high accuracy, that is parallelism (ANCOVA: F = 0.597, df = 1, p = 0.445) and recovery tests (98.2% ± 5.1% and 107.5% ± 18.7%). Further, for biological validation, the change in fGM concentration was examined before and after the transportation of the snow leopards to another zoo. This field‐friendly hormone analysis method is expected to contribute as a simple and rapid stress evaluation tool to manage conservation and animal welfare by monitoring the stress levels.