Activity budget, behavioural activities of pairs and adrenocorticotrophin-induced adrenocortical response in captive Dolichotus patagonum

Abstract

Characterization of behavioural and adrenocortical activities in captive animals is useful to validate techniques and collect normative data. However, those activities may be influenced by human care. The Argentinean endemic Dolichotis patagonum shows diurnal activity and monogamy combined with communal breeding. We aimed to describe 1) activity budget and activities of pairs, and 2) adrenocortical responds to ACTH, and associated changes in biochemical parameters. Adult pairs, previously identified, exposed to natural climatic conditions at Cordoba Zoo (Argentina). Firstly, spontaneous weekly sampling was performed on individuals (n=28) over 35 day-period (spring), recording hourly (8-18h) activities. Secondly, two animals were treated intramuscularly with ACTH (5UI/kg). Post ACTH treatment blood was collected in anaesthetized animals at 0, 15, 30, 60 and 120 minutes. Biochemical measurements by: electrochemiluminescence immunoassay (ECLIA)/Roche: glucocorticoids; Wiener reactive agents: glucose; and automatic haematology counting. Statistical analyses (GLMM) were applied. Behaviour measured (%): resting 46.2±2.1, locomotion 7.4±0.9, alert 12.1±0.5, feeding 22.9±2.5, exploration 4.9±0.7 and others 7.2±1.4; exhibiting statistical differences over hours in feeding (p=0.0019) and alert (p=0.0004). The degree of behavioural synchrony between partners was 60%. Besides, a post-ACTH treatment incremented glucocorticoid (0-15<30-60<120 min; p=0.0016) and glucose (0<15- 30<60-120 min; p=0.0017). Behavioural daily variation could indicate perhaps random effects of management and visitor's presence on feeding and alert behaviours. Besides, preliminary hormonal analysis showed that ECLIA could work for adrenocortical monitoring, and only glucose changes were correlated with. Our advances remark the importance to test sensitive indicators and collect normative validated data in order to then precisely study stressors on wildlife.