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. 
Birolo, M., Trocino, A., Zuffellato, A. et al. 2022. Use of gnawing hay blocks: Effects on productive performance, behavior and reactivity of growing rabbits kept in parks with different sex-group compositions. Animals 12(9), 1212.

To improve animal welfare in collective park housing systems, this study assessed the effects of the provision of gnawing hay blocks and the group composition (F: females, M: males, FM: mixed sex) on performance, behavior...

Aldhshan, M. S., Mizuno, T. M. 2022. Effect of environmental enrichment on aggression and the expression of brain-derived neurotrophic factor transcript variants in group-housed male mice. Behavioural Brain Research 433, 113986.

Social and environmental factors influence behavior via modulation of brain physiological functions. Environmental enrichment (EE) is an animal housing technique that provides complex sensory, motor, and social stimulation, leading to modifications in the innate aggressiveness...

Mieske, P., Hobbiesiefken, U., Fischer-Tenhagen, C. et al. 2022. Bored at home?—A systematic review on the effect of environmental enrichment on the welfare of laboratory rats and mice. Frontiers in Veterinary Science 9, 899219.

Boredom is an emotional state that occurs when an individual has nothing to do, is not interested in the surrounding, and feels dreary and in a monotony. While this condition is usually defined for humans...

Corredor, K., Marín, D. P., García, C. C. et al. 2022. Providing environmental enrichment without altering behavior in male and female Wistar rats (Rattus norvegicus). JAALAS 61(3), 234-240.

In research using animal models, subjects are commonly maintained under standard housing conditions, mainly because of the idea that enhancing welfare conditions could alter experimental data. Another common practice in many laboratories relates to the...

Marques Maia, C., Volpato, G. L., Braithwaite, V. A. 2022. A psychological aversive condition does not change individual zebrafish preference for background color or artificial plant enrichments. Journal of Applied Animal Welfare Science 25(4), 427-438.

Information on fish preference for environmental conditions can be a useful tool to offer them what they want, an important requirement for welfare purposes. Giving that such an approach deals with psychological states of the...

Scariot, P. P., Gobatto, C. A., Polisel, E. E. et al. 2022. Early-life mice housed in standard stocking density reduce the spontaneous physical activity and increase visceral fat deposition before reaching adulthood. Laboratory Animals 56(4), 344-355.

Laboratory rodents spend the entire day housed in standard cages that provide a restricted area for movements and might, therefore, limit physical activity. However, it has not been tested in immature rodents of ages ranging...

Hinchcliffe, J. K., Jackson, M. G., Robinson, E. S. 2022. The use of ball pits and playpens in laboratory Lister Hooded male rats induces ultrasonic vocalisations indicating a more positive affective state and can reduce the welfare impacts of aversive procedures. Laboratory Animals 56(4), 370-379.

The advancement and quality of science rely on research that is robust and unbiased in its experimental design, execution, analysis, and reproducibility. In preclinical research, a better understanding of animal emotions and refinement of their...

Abazaris, J., Hashway, S. 2022. Vole husbandry at Colorado University Boulder. Laboratory Animal Science Professional 10(4) (July/August), 12-15.

Since they arrived at CU Boulder, we have learned a lot about the voles from the laboratory, other institutions, and our trial-and-error. We hope this information can be helpful to any considering adding voles to...

Pantophlet, J., McClusky, D. 2022. Compressed paper column housing enrichment for Naked Mole-rats. Laboratory Animal Science Professional 10(5) (September/October), 42-44.

Naked Mole-rats are relative newcomers in the research world. Due to the complexity of their natural subterranean tunneling system, it has been difficult to replicate in the laboratory environment. Housing standards often differ from the...

Ramírez-Rodríguez, G. B., Gutiérrez-Vera, B., Ortiz-López, L. et al. 2022. Environmental enrichment: Dissociated effects between physical activity and changing environmental complexity on anxiety and neurogenesis in adult male Balb/C mice. Physiology & Behavior 254, 113878.

Several factors, including environmental modifications, stimulate neuroplasticity. One type of neuroplasticity consists in the generation of new neurons in the dentate gyrus of the hippocampus. Neurogenesis is modulated by environmental enrichment (ENR, tunnels plus running...

Spitzer, H. B., Meagher, R. K., Proudfoot, K. L. 2022. The impact of providing hiding spaces to farmed animals: A scoping review. PLOS ONE 17(11), e0277665.

Many wild animals perform hiding behaviours for a variety of reasons, such as evading predators or other conspecifics. Unlike their wild counterparts, farmed animals often live in relatively barren environments without the opportunity to hide...

Córneo, E., Michels, M., Abatti, M. et al. 2022. Enriched environment causes epigenetic changes in hippocampus and improves long-term cognitive function in sepsis. Scientific Reports 12(1), 11529.

Sepsis is defined as a life-threatening organ dysfunction caused by an inappropriate host response to infection. The presence of oxidative stress and inflammatory mediators in sepsis leads to dysregulated gene expression, leading to a hyperinflammatory...

Chrzanowska, A., Modlinska, K., Goncikowska, K. et al. 2022. Rat’s response to a novelty and increased complexity of the environment resulting from the introduction of movable vs. stationary objects in the free exploration test. PLOS ONE 17(12), e0279006.

Most animals, including rats, show a preference for more complex environments. This is demonstrated particularly well when complexity increases due to the addition of new elements to the environment. The aim of the study was...

Mieske, P., Hobbiesiefken, U., Fischer-Tenhagen, C. et al. 2022. Bored at home?—A systematic review on the effect of environmental enrichment on the welfare of laboratory rats and mice. Frontiers in Veterinary Science 9, 899219.

Boredom is an emotional state that occurs when an individual has nothing to do, is not interested in the surrounding, and feels dreary and in a monotony. While this condition is usually defined for humans...

Saraiva, J. L., Rachinas-Lopes, P., Arechavala-Lopez, P. 2022. Finding the “golden stocking density”: A balance between fish welfare and farmers’ perspectives. Frontiers in Veterinary Science 9, 930221.

The effects of stocking density on fish welfare are complex and involve many interacting parameters. This complex relationship between fish welfare, stocking density and influencing factors make it challenging to define a specific optimal (“golden”)...

Tsang, B., Gerlai, R. T. 2022. Common aquarium plants as an enrichment strategy in zebrafish

An increasing number of laboratories utilize zebrafish as this species is now represented in practically every subfield of biology research. Environmental enrichment has been shown to improve welfare and health of a large number of...

Cait, J., Cait, A., Scott, R. W. et al. 2022. Conventional laboratory housing increases morbidity and mortality in research rodents: Results of a meta-analysis. BMC Biology 20(1), 15.

Over 120 million mice and rats are used annually in research, conventionally housed in shoebox-sized cages that restrict natural behaviours (e.g. nesting and burrowing). This can reduce physical fitness, impair thermoregulation and reduce welfare (e.g...

Molina, S. J., Lietti, Á. E., Carreira Caro, C. S. et al. 2022. Effects of early noise exposure on hippocampal-dependent behaviors during adolescence in male rats: Influence of different housing conditions. Animal Cognition 25(1), 103–120.

Central nervous system (CNS) development is a very complex process that can be altered by environmental stimuli such as noise, which can generate long-term auditory and/or extra-auditory impairments. We have previously reported that early noise...

Costa, R., Carvalho, M. S. M., Brandão, J. D. P. et al. 2021. Modulatory action of environmental enrichment on hormonal and behavioral responses induced by chronic stress in rats: Hypothalamic renin-angiotensin system components. Behavioural Brain Research 397, 112928.

Environmental enrichment (EE) has been studied as a protocol that can improve brain plasticity and may protect against negative insults such as chronic stress. The aim of this study was to evaluate the effects of...

Oatess, T. L., Harrison, F. E., Himmel, L. E. et al. 2021. Effects of acrylic tunnel enrichment on anxiety-like behavior, neurogenesis, and physiology of C57BL/6J mice. JAALAS 60(1), 44-53.

Environmental enrichment for mice lags behind the standard enrichment offered to other laboratory rodents due to concerns about environmental variability and, in specific contexts, aggression. Our objective in this study was to evaluate concerns that...

Monnas, J. 2021. DIY: Creating a rat play cage. Laboratory Animal Science Professional 9(2) (March/April), 46-48.

To provide extra enrichment for our training rats (Sprague Dawley; CRL: SD), our team discussed the idea of developing a rat play cage. Animals are housed in the Comparative Bioscience Center at The Rockefeller University...

Li, J.-Y., Kuo, T. B. J., Hung, C.-T. et al. 2021. Voluntary exercise enhances hippocampal theta rhythm and cognition in the rat. Behavioural Brain Research 399, 112916.

Regular exercise promotes learning and memory functions. Theta activity is known to relate to various cognitive functions. An increase in theta power may be related to higher cognitive functioning and learning functions. However, evidence is...

Adcock, A., Choleris, E., Denommé, M. et al. 2021. Where are you from? Female mice raised in enriched or conventional cages differ socially, and can be discriminated by other mice. Behavioural Brain Research 400, 113025.

Laboratory rodents raised in environmentally-enriched (EE) cages differ behaviourally and cognitively from conventionally-housed (CH) animals. We hypothesised that mice can detect such differences, testing this using differentially-raised female C57BL/6 s as subjects, and differentially-raised female...

Marchetto, L., Barcellos, L. J. G., Koakoski, G. et al. 2021. Auditory environmental enrichment prevents anxiety-like behavior, but not cortisol responses, evoked by 24-h social isolation in zebrafish. Behavioural Brain Research 404, 113169.

The zebrafish (Danio rerio) is widely used as a promising translational model organism for studying various brain disorders. Zebrafish are also commonly used in behavioral and drug screening assays utilizing individually tested (socially isolated) fish...

Fischer, M. L., Rodrigues, G. S., Aguero, W. P. et al. 2021. Refinement as ethics principle in animal research: Is it necessary to standardize the environmental enrichment in laboratory animals? Anais da Academia Brasileira de Ciências, 93(1), e20191526.

The Environmental enrichment technique, although scientifically recognized for raising the level of animal welfare, has led to the questioning of its influence on the results of experimental research. Thus, the goal is to promote reflection...