Apparatus for collection of fecal samples from undisturbed spiny mice (Acomys cahirinus) living in a complex social group.

Assessment of fecal glucocorticoid metabolites has become a widely used method for monitoring stress responses. Because most small rodents are social animals whose physiologic parameters are affected by social stimuli, individual housing may compromise these data. Nevertheless, housing rodents in families or social groups may be an important limitation to the experimental design. The challenge is to collect samples from individual rodents while avoiding stress-associated effects from the sampling method itself. Here we present an apparatus and protocol allowing routine repeated collection of an individual rodent's fresh fecal samples without noticeable disturbance of any of the study animals; continuous maintenance of studied animals in a familiar environment; group housing; and uninterrupted visual and olfactory communication among group members during sampling. The apparatus consists of 1 central and 4 lateral compartments. The experimental animal was allowed to enter a lateral compartment voluntarily, where it remained for the short (4 h) period necessary for sample collection before rejoining the rest of the group. Evaluations involved Egyptian spiny mice, a social rodent increasingly studied in laboratories. The results confirmed the repeatability of the assessment of baseline levels of glucocorticoid metabolites. Moreover, keeping the animals in our experimental apparatus did not induce any increase in the levels of glucocorticoid metabolites, even when isolation in the compartment was relatively prolonged. We interpret these results as confirmation that our sampling procedure allows repeated individual sampling within a nearly undisturbed social unit.