Rat Refinements

Evidence-based refinements for rats.

Housing & Handling

In a laboratory setting, it is important to provide housing that allows expression in a wide range of species-typical behaviors while also meeting research goals. Substandard housing can lead to aggression, stereotyping, and anxiety. Understanding the animal’s natural behavior enables us to build quality environments that meet physical, behavioral, and social needs. Proper design is critical for improved health and welfare, both of which improve scientific validity.

Making changes to current housing standards can be challenging especially since facilities may be at very different levels of current housing. Work from where you are currently to make improvements. Furthermore, before implementing housing changes, be sure to consult the relevant scientific literature and consider the requirements of your scientific model. Each facility may require an individual approach to increasing housing standards as much as possible.

Key Natural Behaviors

Recommendations

Stable social groups
Cages that are large & tall enough to allow rats to stand upright, stretch, and climb
Solid floors
Avoid brightly lit home enclosures
Positive handling such as tickling when juveniles
Nesting material, shelters, tubes/climbing structures
Aspen bedding is generally preferable compared to corn cob
Gnawing materials such as wood blocks or chew sticks
Access to digging materials such as deep shaving, dirt, crinkle paper, etc.
Playpens or exercise areas with water trays, running wheel, ladders, ropes, etc. (see more)
Rat tickling and low-stress handling: see our rat tickling facts and questions resource page

Resources

Procedural Refinements

1. Rodent Oral Gavage & Dosing

Flexible feeding tubes for oral dosing are an animal welfare refinement over rigid metal tubes which have been shown to cause significantly more esophageal inflammation as seen in this study from Bristol Myers Squibb
. Plastic gavage needles (seen here) are flexible to reduce the risk of trauma to the esophagus, translucent to visualize delivery, and disposable to eliminate the cost of cleaning and the chance of compound crossover
Micropipette-guided Drug Administration can be used instead of gavage. Mice can be trained to drink medicated fluids which can remove the need for oral gavage from the study (video here)

2. Rodent Blood Sampling

Vascular Access Buttons™ are the preferred method of catheter exteriorization for mice (one or two catheters) and rats (one to four catheters). They offer many advantages such as low-stress and hands-off sampling and infusion, the possibility of group housing after surgery, and extended catheter patency duration. The Vascular Access Button™ has been used for many applications aside from blood sampling and infusion including bile duct collection, organ or subcutaneous infusion, glucose clamping, and has been used successfully with ferrets, rabbits, mini-pigs, and other small rodents
- Provides a way to group house the animals, reduce their stress, and improve data
- If a chronic study requires access to the vascular system and the catheter patency is suboptimal, more animals will unnecessarily need to undergo surgery and be enrolled

Training rats to cooperate with procedures

A group at RISE (Research Institutes of Sweden) also have unique and effective methods for training rodents to cooperate with procedures. Their team focuses on initial handling using gentle techniques and food reinforcements to cooperate with transport, blood sampling, and oral gavage with minimal or even no restraint.

Learn more about their techniques by viewing the videos below and reading the blog post with further videos from 2019 NC3Rs IAT Symposium.

If you know of other resources that you think should be featured on this page, please contact us at contactus@na3rsc.org.