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. 
Blackburn, N., Cronshaw, G., Mitchell, M. 2020. Environmental enrichment for a small colony of rats. Animal Technology and Welfare 19(2), 158.

Due to limited space and resource for equipment, we came up with some easy and cost-effective ways to improve enrichment for the rat colony. Since implementing our protocol for forage feeding and out of cage...

Krueger, L. D., Thurston, S. E., Kirk, J. et al. 2020. Enrichment preferences of singly housed zebrafish (Danio rerio). JAALAS 59(2), 148–155.

Despite the increasing popularity of zebrafish (Danio rerio) as an animal model, the environmental enrichment preferences of this species have been largely unexplored. We sought to determine the preferences of mature female zebrafish that were...

Shomer, N. H., Allen-Worthington, K. H., Hickman, D. L. et al. 2020. Review of rodent euthanasia methods. JAALAS 59(3), 242–253.

The optimal choice of euthanasia method for laboratory rodents depends on a number of factors, including the scientific goals of the study, the need to minimize animal pain and/or distress, applicable guidelines and laws, the...

Laferriere, C. A., Pang, D. S. 2020. Review of intraperitoneal injection of sodium pentobarbital as a method of euthanasia in laboratory rodents. JAALAS 59(3), 254–263.

Euthanasia is one of the most commonly performed procedures in biomedical research, involving tens of millions of animals in North America and Europe every year. The use of sodium pentobarbital, injected intraperitoneally, for killing rodents...

Galex, I. A., Gallant, C. M., D'Avignon, N. et al. 2020. Evaluation of effective and practical euthanasia methods for larval African clawed frogs (Xenopus laevis). JAALAS 59(3), 269–274.

Larval, or tadpole-stage Xenopus laevis frogs are a popular research model for developmental biology and disease studies. Existing euthanasia guidance documents offer recommendations for both eggs and adult stages, yet do not specifically address the...

Khoo, S. Y.-S., Correia, V., Uhrig, A. 2020. Nesting material enrichment reduces severity of overgrooming-related self-injury in individually housed rats. Laboratory Animals 54(6), 546-558.

Individual or singly-housing laboratory rats is common in many animal facilities, but has an adverse impact on the welfare of this social species. It has previously been shown that a small proportion of individually housed...

LaFleur, R. A., Williams-Fritze, M. J. 2020. Now hear this: Caring for chinchillas in research. Laboratory Animal Science Professional 8(5) (September/October), 8-12.

This article describes the authors’ experience with the housing, social housing, husbandry, handling, and environmental enrichment of chinchillas in laboratories.

Worlds, T., Kearney, M., De La Garza, F. et al. 2020. Development of a rabbit enrichment program and contribution to a culture of transparency and care. Laboratory Animal Science Professional 8(6) (November/December), 38-40.

The Becton Dickinson (BD) Research Animal Care Program has developed an acclimation and enrichment program that has enhanced animal welfare for studies requiring single housing, contributed to a culture of care, increased transparency, and improved...

Gabriel, P., Mastracchio, T., Bordner, K. et al. 2020. Impact of enriched environment during adolescence on adult social behavior, hippocampal synaptic density and dopamine D2 receptor expression in rats. Physiology & Behavior, 226, 113133.

Environmental enrichment (EE) is one experimental manipulation that induces changes in the brain. However, it is important to distinguish between physical and social components of enrichment. To this end we established four groups of rats...

Keymoradzadeh, A., Hedayati Ch, M., Abedinzade, M. et al. 2020. Enriched environment effect on lipopolysaccharide-induced spatial learning, memory impairment and hippocampal inflammatory cytokine levels in male rats. Behavioural Brain Research 394, 112814.

Neuro-inflammation is responsible for cognitive impairments and neurodegenerative diseases such as Alzheimer’s disease. In this study, we aimed to investigate the enriched environment (EE) effect on learning and memory impairment as well as on pro-inflammatory...

Modlinska, K., Chrzanowska, A., Pisula, W. 2020. Variability of enriched environment does not enhance the enrichment effect on food neophobia in rats (Rattus norvegicus). Behavioural Processes 180, 104221.

Many studies report differences between animals raised in an enriched environment and those living in standard conditions. Animals reared in enriched conditions demonstrate better memory and learning abilities, increased activity, reduced level of anxiety, etc...

Natusch, D. J. D., Aust, P. W., Khadiejah, S. et al. 2020. Behavioral and corticosterone responses to carbon dioxide exposure in reptiles. PLOS ONE 15(10), e0240176.

The use of carbon dioxide (CO2) exposure as a means of animal euthanasia has received considerable attention in mammals and birds but remains virtually untested in reptiles. We measured the behavioral responses of four squamate...

Kulkarni, S., Hickman, D. 2020. Isoflurane and carbon dioxide elicit similar behavioral responses in rats. Animals 10(8), 1431.

Euthanasia in rodents is an ongoing topic of debate due to concerns regarding the aversive nature of gases with anesthetic properties such as carbon dioxide (CO2) and isoflurane. The aim of this study was to...

Coda, K. A., Fortman, J. D., García, K. D. 2020. Behavioral effects of cage size and environmental enrichment in New Zealand white rabbits. JAALAS 59(4), 356-364.

One of the goals of environmental enrichment is to encourage species-typical behaviors, while discouraging abnormal behaviors or stereotypies. Assessing the effectiveness of various enrichment modalities can be challenging, particularly for prey species such as rabbits...

Rojas-Carvajal, M., Sequeira-Cordero, A., Brenes, J. C. 2020. Neurobehavioral effects of restricted and unpredictable environmental enrichment in rats. Frontiers in Pharmacology 11, 674.

To study how motivational factors modulate experience-dependent neurobehavioral plasticity, we modify a protocol of environmental enrichment (EE) in rats. We assumed that the benefits derived from EE might vary according to the level of incentive...

Tan, S. L. T., Handasyde, K. A., Rault, J.-L. et al. 2020. Insensitivity to reward shifts in zebrafish (Danio rerio) and implications for assessing affective states. Animal Cognition 23(1), 87–100

Theory and empirical findings predict that individuals in a negative affective state are more sensitive to unexpected reward loss and less sensitive to unexpected reward gain compared to individuals in a neutral or positive affective...

Leenaars, C. H. C., Pels, E. G. M., Joosten, R. N. J. M. A. et al. 2019. Wistar rats do not show preference for either of two commonly used nutritionally sound food rewards in a T-maze. Journal of Veterinary Behavior 31, 22-27.

Food rewards are commonly used as positive reinforcement in rodent behavioral experiments. Bioserv dustless precision pellets and Noyes formula P precision pellets are both used for this purpose in behavioral experiments in multiple laboratories, as...

Heyworth, C., Owens, D. 2019. Eureka! Enhanced water recipe and enrichment for oocyte quality and embryo development in the African clawed frog (Xenopus laevis). Laboratory Animal Science Professional 7(1) (March), 43-45.

Husbandry staff set a goal to develop a health monitoring program for a Xenopus laevis colony that included not only specific pathogen freedom, but wellness. This article describes environmental enrichment and a water recipe for...

Lynch, C. A., Porter, B., Butler, T. R. 2019. Access to voluntary running wheel exercise: Prevention of anxiety-like behavior in chronically stressed rats, but potentiation of ethanol intake/preference. Physiology & Behavior 206, 118-124.

The current study tested the effect of voluntary running on future anxiety-like behavior, physiological response to stress, and ethanol intake/preference, while including a chronically stressed group and healthy group housed conspecifics. When given concurrently, voluntary...

Améndola, L., Ratuski, A., Weary, D. M. 2019. Variation in the onset of CO2-induced anxiety in female Sprague Dawley rats. Scientific Reports 9, 19007.

Carbon dioxide (CO2) is commonly used to kill laboratory rats. Rats find CO2 aversive and aversion varies between individuals, indicating that rats vary in CO2 sensitivity. Healthy humans experience feelings of anxiety at concentrations similar...

Cox, R. J., Nol, P., Ellis, C. K. et al. 2019. Research with agricultural animals and wildlife. ILAR Journal 60(1), 66-73.

In fiscal year 2016, agricultural animals such as swine, sheep, goats, and cattle represented 10% of the 820 812 animals used in USDA-regulated research. In addition to traditional agricultural animals, research studies using captive wildlife...

Dunford, K., Hakkesteeg, J., Wilson, C. 2019. Stiff as a board: Measuring rigor mortis in zebrafish. Animal Technology and Welfare 18(3), 203-205.

Schedule one killing (S1K) methods require a two-step process: a humane method of death, typically for Zebrafish an anaesthetic overdose and confirmation of death, such as confirmation of rigor mortis. There is widespread variation of...

Thurman, C. E., Rasmussen, S., Prestia, K. A. 2019. Effect of 3 euthanasia methods on serum yield and serum cortisol concentration in zebrafish (Danio rerio). JAALAS 58(6), 823–828.

Zebrafish are an important model in neuroscience and developmental biology and are also an emerging model in hematology and immunology. Little information is available for zebrafish regarding the physiologic impact of different euthanasia methods and...

Morano, R., Hoskins, O., Smith, B. L. et al. 2019. Loss of environmental enrichment elicits behavioral and physiological dysregulation in female rats. Frontiers in Behavioral Neuroscience 12, 287.

Chronic stress drives behavioral and physiological changes associated with numerous psychiatric disease states. In rodents, the vast majority of chronic stress models involve imposition of external stressors, whereas in humans stress is often driven by...

Makowska, I. J., Weary, D. M. 2019. A good life for laboratory rodents? ILAR Journal 60(3), 373-388.

Most would agree that animals in research should be spared “unnecessary” harm, pain, or distress, and there is also growing interest in providing animals with some form of environmental enrichment. But is this the standard...