title: Co-species housing in mice and rats: effects on physiological and behavioral stress responsivity.
abstract: Co-species housing of mice and rats is common practice at most breeding facilities and research laboratories, neglecting the possible effects on the animals. We investigated physiological as well as behavioral stress-reactivity in mice and rats which were either derived from a co-species or species-separated housing condition at the breeding facilities. The animals were kept under the housing condition they were used to or assigned to the opposite one. Co-species housing had a significant impact on acute stress reactivity in mice and rats but only if they were used to this housing condition throughout their lives. Moreover, the stress-effects appeared to be long lasting. Assigning animals, derived from a species-separated housing condition, to co-species housing led to chronic stress in mice and affected experimental behavior of rats. Our findings led to the conclusion that co-species housing in mice and rats should be avoided, supporting the recommendations by the U.S. National Institutes of Health (NIH) and the Dutch Ministry of Health, Welfare and Sport (VWS). In order to support the interpretation, facilitate the reproducibility and comparability and subsequently the generalizability of experimental results, breeding facilities should at least provide detailed information about their housing conditions.
authors.affiliation: Department of Animals in Science & Society, Division of Laboratory Animal Science, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands. s.s.arndt@uu.nl
authors.forename: Saskia S
authors.initials: SS
authors.lastname: Arndt
authors.forename: Dissaya
authors.initials: D
authors.lastname: Lohavech
authors.forename: José
authors.initials: J
authors.lastname: van't Klooster
authors.forename: Frauke
authors.initials: F
authors.lastname: Ohl
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism / Q000473:pathology; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology*; D035843:Biomedical Research / Q000379:methods; D002908:Chronic Disease; D006799:Housing, Animal; D006854:Hydrocortisone / Q000097:blood; D008297:Male; D051379:Mice / Q000502:physiology*; D008807:Mice, Inbred BALB C; D009483:Neuropsychological Tests; D011897:Random Allocation; D051381:Rats / Q000502:physiology*; D017207:Rats, Sprague-Dawley; D013315:Stress, Psychological / Q000473:pathology / Q000503:physiopathology*; D013550:Swimming; D013950:Thymus Gland / Q000378:metabolism / Q000473:pathology; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D014446:Tyrosine 3-Monooxygenase; D006854:Hydrocortisone