The use of temporary enrichment by laboratory rats (Rattus norvegicus) : does different types of temporary enrichment effect the behaviours of laboratory rats?

Abstract: Enrichment for laboratory animals is widely discussed and it is getting more commonly known as something that can help with increasing the animal welfare. However, more studies are needed in how enrichment is used and how it affects animal behaviour. Seventeen male rats of the strain Lewis were given three different types of temporary enrichment types; cardboard, paper and fabric. The rats were filmed during three weeks and their behaviours were analysed. An ethogram was used to determine if there was a difference regarding interaction with enrichment types, activity levels and negative behaviours. The rats interacted with the temporary enrichment differently during the two weeks when temporary enrichment was offered, compared to the first control week where no extra enrichment was given. During the first week with temporary enrichment the rats interacted the most with cardboard, but during the second week they interacted the most with the fabric. Resting behaviours where the highest during the week where the animals did not have access to extra enrichment. Active behaviours where the highest during the first week with extra enrichment, and the lowest the second week with enrichment. When the rats did not have access to temporary enrichment they had more negative social behaviours than positive social behaviour. When the temporary enrichment was introduced the positive social behaviours increased whereas the negative social behaviours decreased during both weeks. Enrichment should be used in a laboratory setting to increase the animal welfare. It is important that different types of enrichment is being offered to increase the opportunity of performing a more broad spectra of natural behaviours in the rats.