Issues with conventional rodent housing, playpens for rats, and using sleep to assess welfare


It’s the 3rd Thursday of February, and you’re listening to 3 Minute 3Rs. This month, we’re bringing you 3 refinement papers. Let’s start with rodent housing.

Research rodents are conventionally housed in shoebox sized cages that limit their ability to perform natural behaviors such as nesting and burrowing. These restrictions are known to impair welfare, but could they even increase disease risk and shorten lifespans? A new meta-analysis compares the morbidity and mortality of rodents in conventional vs enriched housing. Conventional housing was found to significantly worsen disease severity for cancer, cardiovascular disease, stroke, anxiety, and depression. Conventional housing also increased all-cause mortality. In conclusion, conventional housing appears to be distressing enough to compromise rodent health in a biologically significant manner. This lends more evidence to the importance of refining rodent housing for ethical, validity, and translational reasons. To learn more, read the full paper online.

Sticking with the rodent theme, if you work with rats, you might find standard cages don’t provide enough room for a fully enriched environment – one where rats can socialize, exercise and express natural behaviours. If larger cages are not currently an option, two solutions with increasing research to back them up are playpens and ball pits, the focus of a recent paper in LA.

Justyna Hinchcliffe et al. describe using 50 kHz ultrasonic vocalisations as an objective, quantifiable measure of how rats responded to ball pits and playpens. They found that these vocalisations were more frequent for rats exposed to the enriched environments, when compared with control conditions. They also tested the effect of playpens and ball pits on rats given an aversive drug treatment, finding that exposure to these environments reduced its negative impact. Besides the important welfare benefits of environmental enrichment, there are also scientific benefits in the shape of reduced variability and therefore more reliable results. With new evidence supporting the use of playpens for rats to minimize stress, there has never been a better time to try them out in your facility.

And finally, let’s see how sleep could be a helpful tool to help us track laboratory animal welfare.

In humans, sleep quality is strongly related to a person’s well-being and recent research suggests the same may be true in laboratory animals, such as dogs. If this is the case, sleep quality may then be useful as a non-invasive measure of animal welfare. A study in Sci. Rep. examined this hypothesis further using an observational approach to characterize sleeping patterns in laboratory dogs and investigate the effects of sleep quality on their daily behaviors. Male and female adult dogs housed in kennels in Brazil were recorded during a continuous 24-h, five-day assessment period. The footage was then analysed for daytime behaviours and sleeping metrics, such as number of sleep bouts and their duration. The study showed that the dogs slept far less than reported previously in the literature and during the day they were less active, ate more, played less and were less alert. Alterations of these daytime behaviors as a result of loss of sleep may indicate compromised welfare highlighting appropriate measures should be taken to ensure lab dogs’ sleep quality and welfare. 

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