title: Effects of housing density in five inbred strains of mice.
abstract: To evaluate the effect of increased mouse density in a cage, mice were housed at the density recommended by the 1996 Guide for the Care and Use of Laboratory Animals and at densities that were approximately 2, 2.6, and 3 times greater. Five strains of mice (129S1/SvImJ, A/J, BALB/cByJ, C57BL/6J, and DBA/2J) were evaluated throughout 3- and 8-month timeframes for health and well-being, including mortality, cardiac measures, plasma cholesterol, body weight, bone mineral density, organ weights, hematology, behavioral observations, and open field and light-dark tests. For 22 of the 27 traits measured, increased housing density had no significant effect. Kidney weight, adrenal weight, and heart rate decreased as mice were housed more densely, and some of the decreases were statistically significant. Reduced kidney weight, adrenal weight, and heart rate are not considered to be negative outcomes and may even indicate reduced stress. However, all measurements of these three traits were within normal physiological ranges. Percent fat increased slightly in strains 129S1/SvImJ, A/J, and DBA/2J, but did not increase in strains BALB/cByJ, and C57BL/6J. These results indicate that mice can be housed at higher densities than those currently recommended.
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Judith L
authors.initials: JL
authors.lastname: Morgan
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Svenson
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Lake
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Weidong
authors.initials: W
authors.lastname: Zhang
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Stearns
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Michael A
authors.initials: MA
authors.lastname: Marion
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Luanne L
authors.initials: LL
authors.lastname: Peters
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Beverly
authors.initials: B
authors.lastname: Paigen
authors.affiliation: The Jackson Laboratory, Bar Harbor, Maine, United States of America.
authors.forename: Leah Rae
authors.initials: LR
authors.lastname: Donahue
mesh_terms: D000827:Animal Welfare; D000818:Animals; D001522:Behavior, Animal; D001772:Blood Cell Count; D001794:Blood Pressure; D001835:Body Weight; D015519:Bone Density; D002784:Cholesterol / Q000097:blood; D005260:Female; D006339:Heart Rate; D006799:Housing, Animal; D007756:Laboratory Animal Science / Q000379:methods; D016014:Linear Models; D008297:Male; D008815:Mice, Inbred Strains; D009929:Organ Size
chemical_list: D002784:Cholesterol