Non-invasive Biomarker Sampling Protocol

Saliva and fecal samples were collected twice a month during the 2nd and 4th week between 10.00–12.00 h, to avoid variation in circadian rhythms of cortisol [33 (link),43 (link)]. Saliva was collected using a Salivette^® kit (Sarstedt, AG&Co, Numbrecht, Germany) and harvested by centrifuging at 1500× g for 2 min at 15 °C [42 (link)]. Fecal balls were mixed and approximately 20 g was collected into two separate zip-lock bags. All samples were transported in a 2–8 °C container box [42 (link)] to the Faculty of Veterinary Medicine, Chiang Mai University. All samples were stored at −20 °C until analysis [42 (link),44 (link),45 (link)]. Fecal samples were extracted as described previously for GCs [34 (link),42 (link)] and IgA [42 (link),46 (link)].