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

Abstract

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 husbandry, housing, and handling are important goals in providing good animal welfare in a laboratory setting which underpins rigorous research quality. Induction of positive emotional state in animals is a key component of their well-being, and one approach is to increase their environmental complexity using, for example, ball pits or playpens in rats. In this study, we recorded 50 kHz ultrasonic vocalisations (USVs) during animals’ exposure to the ball pit and playpen. We have previously shown that 50 kHz USVs provide a graded and quantifiable measure of an animal’s emotional state, and here find that access to the ball pit and playpen increases 50 kHz USVs, indicative of a more positive affective state. Using our affective bias test (ABT) we next quantified the animals’ emotional response to an aversive intervention and whether this could be attenuated by access to a playpen. The playpen exposure completely mitigated the negative affective state induced by an anxiogenic drug when compared with animals who experienced the drug in the home cage. Together, these findings suggest ball pits and playpens provide a simple and effective method to improve the welfare of laboratory rats and reduce the cumulative suffering they experience from their housing conditions and minor, aversive procedures.

Developing guidelines for pet rat housing through expert consultation

“…However, it is nevertheless important to ask the question of whether and in what ways guidelines for the welfare of the same species should vary according to the purposes for which they are being kept. Indeed, this issue is just one part of the continuing progression of animal welfare regulation; for example, the need for laboratory rats to be able to rear fully in their cages and the use of playpens for enrichment have received growing attention 8,9,12,42,43 …”

“…Indeed, this issue is just one part of the continuing progression of animal welfare regulation; for example, the need for laboratory rats to be able to rear fully in their cages and the use of playpens for enrichment have received growing attention. 8,9,12,42,43 During the development of these guidelines, there were some areas of conflict. For example, there was much disagreement about how to rank the different aspects of rat housing.…”

“…Indeed, this issue is just one part of the continuing progression of animal welfare regulation; for example, the need for laboratory rats to be able to rear fully in their cages and the use of playpens for enrichment have received growing attention. 8 , 9 , 12 , 42 , 43 …”

Stage 1 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats

“…It is therefore likely that ‘happy animals make good science’ ( Grimm, 2018 ; Poole, 1997 ). For instance, positive welfare might reduce stress caused by aversive procedures ( Hinchcliffe et al , 2022 ). For laboratory rats, a positive handling approach referred to as rat tickling is proposed as an effective and practical approach to positively improve their welfare ( https://www.nc3rs.org.uk/rat-tickling ; https://na3rsc.org/rodent-handling/ ).…”

Stage 1 Registered Report: Refinement of tickling protocols to improve positive animal welfare in laboratory rats

“…It is therefore likely that 'happy animals make good science' (Grimm, 2018;Poole, 1997). For instance, positive welfare might reduce stress caused by aversive procedures (Hinchcliffe et al, 2022). For laboratory rats, a positive handling approach referred to as rat tickling is proposed as an effective and practical approach to positively improve their welfare (https://www.nc3rs.org.…”