Reed, M., Goldsteen, D. L., Moore, E. et al. 2011. Environmental enrichment program in transgenic mouse breeding colonies. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 779 (Abstract #P160).

Results of studies on the benefits of environmental enrichment in group-housed mice and breeding colonies are often inconsistent and conflicting. After observing a significant drop in some of the genetically engineered mice (GEM) breeding colonies during a major construction project in an adjacent building, an environmental enrichment and nutritional supplementation program was implemented in order to determine if these changes could salvage colonies at risk. During the construction, many of the 12 strains monitored experienced a decrease in reproductive performance (average litter size, average number of litters born per female, and survival). In order to determine if enrichment was effective, 10 types of nutritional supplements, 4 types of nesting material, and 3 types of huts were tried in every breeding cage. After an 8-mo trial period we empirically determined that 3 types of nutritional supplements were consumed more readily, one type of nesting created the best nesting instinct among the mice and plastic huts were most useful in that they did not block the water valves. Approximately 4 mo after the program was initiated a 2-fold increase in production for the 3 most affected colonies was documented. The program was also simultaneously implemented in 4 colonies that had stable reproductive performance during the construction period and no change in this status was observed. The results of this practical approach to transgenic colony management suggests that when risks of losing valuable mouse strains are encountered, implementation of an environmental enrichment with nutritional supplements program may be highly beneficial.