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DVC® proves to be effective in identifying mouse cages with patterns of high activity levels, signaling possible aggression incidences, thus potentially allowing for early intervention and consequently improving animal welfare.

In the article “Effect of Environmental Enrichment on Aggression in BALB/cJ and BALB/cByJ Mice Monitored by Using an Automated System” published by Journal of the American Association for Laboratory Animal Science (Vol 57, No 3 - 2018 May 2018) by the American Association for Laboratory Animal Science, authors Jareca M Giles, Julia W Whitaker,  Sheryl S Moy, and Craig A Fletcher (Division of Comparative Medicine and Carolina Institute for Developmental Disabilities and Department of Psychiatry, University of North Carolina at Chapel Hill,Chapel Hill, North Carolina) focused their attention on the aggression among mice and how it remains a common undesirable problem in laboratory settings, and animal welfare and scientific outcomes may become compromised depending on the severity of aggression.

This study evaluated the effect of cage enrichment on intra-cage male aggression over a 6-wk period. A bi-level mounted ‘mezzanine’ was used in comparison to a cotton square or shelter. This was the team's first study involving home-cage behavioral challenges to male mice from a high aggression sub strain (BALB/cJ) and low-aggression substrain (BALB/cByJ).

At first, aggressive interactions and locomotor activity were scored manually and then compared to the measurements obtained by the DVC® System. Based on the observations, the BALB/cJ mice exhibited similar levels of aggression across housing conditions, whereas BALB/cByJ mice had lower aggression when housed with a mezzanine.

In a second study, video recordings and continuous DVC® automated measures were collected over 24 h and divided into 12-h light and dark phases. The results showed how BALB/cByJ mice—but not BALB/cJ—mice had increased aggressive behaviors during the dark phase. However, thanks to the DVC®, authors were able to detect higher activity levels during the dark phase, compared with the light phase, in both substrains. Elevated activity levels recorded by the DVC® correlated with fighting bouts and high levels of locomotion. These results show that a bi-level structural form of enrichment reduces aggression, depending on the BALB/c substrain, and confirms higher aggression levels in the BALB/cJ substrain.

In addition, the authors’ findings provide evidence that the DVC® system is effective in identifying mouse cages with patterns of high activity levels, signaling possible aggression incidences, thus potentially allowing for early intervention and consequently improving animal welfare.