Coke-Murphy, C. S., Saborido, T. P., Buendia, M. et al. 2012. Shelter-style environmental enrichment affects neurobehavioral status of laboratory mice. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 639-640 (Abstract #PS47).

Environmental enrichment aims to improve the wellbeing of laboratory animals and provides an opportunity to improve experimental reliability and validity. Animals raised in more stimulating environments have improved learning and memory as well as more complex brain architecture. However, the effects of environmental enrichment on motor performance, anxiety and emotional development have been poorly studied. Most investigators studying the effects of enrichment provide extremely large and complex housing condition so as to maximize the likelihood of finding an effect. These situations are difficult to replicate across animal facilities and are not operationally practical. In this experiment, simple, inexpensive disposable shelter-style enrichment items were used and the extent to which these items alter behavior in C57BL/6 and 129S6 mice was investigated. Breeding pairs were established in the presence of a refuge, dome, or no added enrichment. Offspring were assessed neurobehaviorally, either just after weaning (preadolescent, P22 to P25), or as young adults (P60 to P90). Major strain differences were observed in open field activity levels, elevated maze exploration, Y-maze activity levels, and novel object recognition. The effects of environmental enrichment were more modest than those of strain, and more pronounced in preadolescent mice. Enrichment did alter motor activity, learning, memory, and anxiety state in both pre- and adolescent mice, but was mainly neutral for adolescent mice. The experiments provide a detailed analysis of the effects of simple, inexpensive, and practical methods of housing enrichment on biobehavioral phenotypes in these 2 commonly used inbred strains of laboratory mice.