An explorative study on the effect of provision of preferred and non-preferred enrichment on behavioural and physiological parameters in laboratory ferrets (Mustela putorius furo)

Environmental enrichment is often advocated to refine animal studies. Despite the increasing use of ferrets as an animal model in biomedical research, the knowledge on effects of the provision of enrichment on these animals is limited. Additionally, it is unknown whether varying types of enrichment (i.e. preferred and non-preferred) have a different effect. Therefore, to explore the behavioural and physiological effects of providing (differently valued) enrichment to ferrets, three groups of six female ferrets were housed in standard conditions (with bedding, a flexible bucket, a food bowl and a water nipple), with additional non-preferred enrichment (with two ferret balls, a golf ball and an extra food bowl) and with additional preferred enrichment (with two hammocks, a foraging ball and a water bowl) for eight weeks. At the beginning and end of this period, behavioural (i.e. time spent on food and water intake, elimination, maintenance, inactivity, enrichment interaction, exploration, play, and agonistic behaviour) and physiological (i.e. bodyweight and eutrophil/Lymphocyte ratio [N/L ratio]) parameters were recorded and compared. Results showed that agonistic behaviour increased in the ferrets housed in standard conditions, which was not observed in ferrets that were provided with preferred or nonpreferred enrichment. In addition, the ferrets housed with preferred enrichment showed an increase in social play behaviour and a decrease in rearing behaviour (as part of the exploratory behaviours) which were not observed in the ferrets housed in standard conditions or with non-preferred enrichment. Moreover, the ferrets housed with preferred enrichment showed a clear preference for being inactive in the hammock and drinking from the water bowl. As there was only one cage per condition, the results of this explorative study should be considered preliminary and tentative. Nevertheless, the results are a first indication that providing laboratory ferrets with preferred enrichment has positive effects on their behaviour that are not observed in ferrets provided with non-preferred enrichment or housed in standard conditions. Therefore, we recommend to house laboratory ferrets with a hammock, foraging ball and water bowl as these enrichments might help to refine studies using ferrets