Refinement Database

Database on Refinement of Housing, Husbandry, Care, and Use of Animals in Research

This database, created in 2000, is updated every four months with newly published scientific articles, books, and other publications related to improving or safeguarding the welfare of animals used in research.

Tips for using the database:

  • This landing page displays all of the publications in the database.
  • Use the drop-down menus to filter these publications by Animal Type, Setting, and/or Topic.
  • Clicking on a parent category (e.g., Rodent) will include publications relating to all the items in that category (e.g., Chinchilla, Gerbil, Guinea Pig, etc.).
  • You may also add a keyword to further narrow your search.
  • Please note that at this time, only publications dated 2010 or later (with some exceptions) can be filtered by Animal Type and Topic, and only publications dated 2020 or later (with some exceptions) can be filtered by Setting. Most publications older than 2010 can only be searched by keyword. 
Collymore, C., Tolwani, R. J., Rasmussen, S. 2015. The behavioral effects of single housing and environmental enrichment on adult zebrafish (Danio rerio). JAALAS. 54(3), 280-285.

Environmental enrichment provides laboratory-housed species the opportunity to express natural behavior and exert control over their home environment, thereby minimizing stress. We sought to determine whether providing an artificial plant in the holding tank as...

Miller, A. L., Leach, M. C. 2015. Using the mouse grimace scale to assess pain associated with routine ear notching and the effect of analgesia in laboratory mice. Laboratory Animals 49(2), 117-120.

Social housing is recommended where possible for laboratory mice. In order to achieve this, mice must be individually identifiable. Although, various methods are available, permanent identification is often required, such as ear notching. This method...

Shams, S., Chatterjee, D., Gerlai, R. 2015. Chronic social isolation affects thigmotaxis and whole-brain serotonin levels in adult zebrafish. Behavioral Brain Research 292, 283-87.

The popularity of the zebrafish has been growing in behavioral brain research. Previously utilized mainly in developmental biology and genetics, the zebrafish has turned out to possess a complex behavioral repertoire. For example, it is...

Jirkof, P. 2015. Effects of experimental housing conditions on recovery of laboratory mice. Lab Animal 44(2), 65-70.

The beneficial effects of environment and social support during disease recovery in humans are widely accepted. Because laboratory mice are social animals and are highly motivated to interact with each other and with their environment...

Maher, R. L., Barbash, S. M., Lynch, D. V. et al. 2015. Group housing and nest building only slightly ameliorate the cold stress of typical housing in female C57BL/6J mice. American Journal of Physiology 308(12), R1070-R1079.

Huddling and nest building are two methods of behavioral thermoregulation used by mice under cold stress. In the laboratory, mice are typically housed at an ambient temperature (Ta) of 20°C, well below the lower end...

Bayne, K. A., Beaver, B. V., Mench, J. A. et al. 2015. Laboratory animal behavior. In: Laboratory Animal Medicine, 3rd edition. Fox, J. G., Anderson, L., Otto, G., et al. (eds). Elsevier, Inc., Amsterdam, NL. pp. 1617-1651.

The study of laboratory animal behavior has increased steadily over the last decade, with expanding emphasis on a variety of commonly used species. In the United States, this trend was initially focused on species for...

Baszczak, J. A. 2014. An easy solution for social housing larger guinea pigs in research. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 565 (Abstract #P61).

The standard microisolation caging for guinea pigs, Cavia porcellus, allows for group housing up to a combined weight of 350 g. However, as mandated by the USDA, research facilities must socially house guinea pigs with...

Lidfors, L., Wichman, A., Ewaldsson, B. et al. 2014. Enriched cages for groups of laboratory male rats and their effects on behaviour, weight gain and adrenal glands. Laboratory Animals 48, 36-49.

We investigated if there were any negative effects on the behaviour and physiology of rats housed in groups of five in two types of enriched cages and compared them with paired-housed rats housed in traditional...

Kalliokoski, O., Teilmann, A. C., Jacoben, K. R. et al. 2014. Do singly housed male mice get lonely? Evidence of depressive states after short-term single housing of BALB/c and C57BL/6 mice. American Association for Laboratory Animal Science [AALAS] Meeting Official Program, 597. (Abstract #P184).

Through behavioral and preference studies we know that mice prefer company. Laboratory mice should thus never be housed alone, if a viable option exists. Yet single housing is a fairly common practice, in particular with...

Gaskill, B. 2014. Aggression in laboratory mice: Potential influences and how to manage it. Enrichment Record 18, 22-25.

Aggression is a naturally occurring behavior of mice that can provide benefit to those that display it in the wild. Many factors appear to influence these negative social interactions between mice, making mitigation in the...

Doulames, V., Lee, S., Shea, T. B. 2014. Environmental enrichment and social interaction improve cognitive function and decrease reactive oxidative species in normal adult mice. International Journal of Neuroscience 124(5), 369-376.

Environmental stimulation and increased social interactions stimulate cognitive performance, while decrease in these parameters can exacerbate cognitive decline as a function of illness, injury, or age. We examined the impact of environmental stimulation and social...

Greenberg, G. D., Howerton, C. L., Trainor, B. C. 2014. Fighting in the home cage: Agonistic encounters and effects on neurobiological markers within the social decision-making network of house mice (Mus musculus). Neuroscience Letters 566, 151-155.

Inbred strains of mice, such as C57Bl/6, have become preferred animal models for neurobehavioral studies. A main goal in creating inbred lines is to reduce the effects of individual genetic variation on observed phenotypes. Most...

Grippo, A. J., Ihm, E., Wardwell, J. et al. 2014. The effects of environmental enrichment on depressive and anxiety-relevant behaviors in socially isolated prairie voles. Psychosomatic Medicine 76(4), 277-284.

Social isolation is associated with depression, anxiety and negative health outcomes. Environmental enrichment, including environmental and cognitive stimulation with inanimate objects and opportunities for physical exercise, may be an effective strategy to include in treatment...

Hori, M., Yamada, K., Ohnishi, J. et al. 2014. Tickling during adolescence alters fear-related and cognitive behaviors in rats after prolonged isolation. Physiology & Behavior 131, 62-67.

Social interactions during adolescence are important especially for neuronal development and behavior. We recently showed that positive emotions induced by repeated tickling could modulate fear-related behaviors and sympatho-adrenal stress responses. In the present study, we...

Krügel, U., Fischer, J., Bauer, K. et al. 2014. The impact of social isolation on immunological parameters in rats. Archives of Toxicology 88(3), 853-855.

In various toxicological studies, single housing of rodents is preferred to standardize for regulatory purposes. However, housing conditions can have severe, often underestimated, impact on results in toxicological examinations. As different husbandry conditions have been...

Kulesskaya, N., Karpova, N. N., Ma, L. et al. 2014. Mixed housing with DBA/2 mice induces stress in C57BL/6 mice: Implications for interventions based on social enrichment. Frontiers in Behavioral Neuroscience 8, 257.

Several behavioral interventions, based on social enrichment and observational learning are applied in treatment of neuropsychiatric disorders. However, the mechanism of such modulatory effect and the safety of applied methods on individuals involved in social...

Monteiro, B. M., Moreira, F. A., Massensini, A. R. et al. 2014. Enriched environment increases neurogenesis and improves social memory persistence in socially isolated adult mice. Hippocampus 24(2), 239-248.

Social memory consists of the information necessary to identify and recognize cospecifics and is essential to many forms of social interaction. Social memory persistence is strongly modulated by the animal's experiences. We have shown in...

Sharp, J., Azar, T., Lawson, D. 2014. Effects of a complex housing environment on heart rate and blood pressure of rats at rest and after stressful challenges. JAALAS 53(1), 52-60.

Housing enrichment for rodents continues to be a discussion topic within the animal care community. The objective of this study was to determine the extent to which a complex housing environment affects heart rate, blood...

Turner, P. V., Sunohara-Neilson, J., Ovari, J. et al. 2014. Effects of single compared with pair housing on hypothalamic-pituitary-adrenal axis activation and low-dose heroin place conditioning in adult male Sprague-Dawley rats. JAALAS 53(2), 161-167.

Whether social isolation of adult rats under standard laboratory conditions produces significant long-term alterations in behavior and physiology is unclear. In the present study, male Sprague–Dawley rats were singly or paired-housed for 10 wk. During...

Vaughan, L. M., Dawson, J. S., Porter, P. R. et al. 2014. Castration promotes welfare in group-housed male Swiss outbred mice maintained in educational institutions. JAALAS 53(1), 38-43.

Educational institutions maintain group-housed mice of both sexes for training veterinarians and technicians in husbandry, medication, and sampling procedures. Mice kept in all-male groups may experience poor welfare due to fighting. Castrated mice may be...

Verma, R., Friedler, B. D., Harris, N. M. et al. 2014. Pair housing reverses post-stroke depressive behavior in mice. Behavioural Brain Research 269, 155-163.

Social isolation (SI) has been linked epidemiologically to high rates of morbidity and mortality following stroke. In contrast, strong social support enhances recovery and lowers stroke recurrence. However, the mechanism by which social support influences...

Abou-Ismail, U. A., Darwish, R. A., Ramadan, S. G. A. 2014. Should cages of laboratory rats be enriched physically or socially? Global Veterinaria 13(4), 570-582.

Experiments of environmental enrichment usually compare between group-housed rats in enriched and unenriched cages or between group-housed rats in enriched cages and single-housed rats in unenriched cages. This bias is mainly to maximize the chance...

Annas, A., Bengtsson, C., Tornqvist, E. 2013. Group housing of male CD1 mice: Reflections from toxicity studies. Laboratory Animals 47(2), 127-129.

Owing to their naturally aggressive behaviour, male mice are often housed individually in toxicity studies. However, several publications advocate group-housing of mice to enable normal social behaviour and interactions between the animals. This refinement project...

Reinhardt, V. (ed.) 2013. Compassion Makes a Difference - Discussions by the Laboratory Animal Refinement & Enrichment Forum [LAREF], Volume III. Animal Welfare Institute, Washington, DC.

This is the third volume of discussions that took place on the Laboratory Animal Refinement & Enrichment Forum (LAREF). This forum is dedicated to the exchange of personal experiences of refining the conditions under which...

Winnicker, C. 2013. Challenges and opportunities of implementing EU standards for social housing of rodents. Enrichment Record 15, 3-4.

The EU Directive on the protection of animals used for scientific purposes specifically states: Animals, except those which are naturally solitary, shall be socially housed in stable groups of compatible individuals. Even in cases where...