Impact of shelter enrichment of metabolic cages in studies of protein metabolism
Metabolic cage housing of laboratory animals is necessary within a wide range of nutritional, metabolic, pharmacokinetic and pharmacodynamic studies in both basic and applied nutritional and biomedical research. It allows accurate measures of food and water intake and urinary and faecal output, but restrained living space, use of grid flooring, absence of bedding substrate and enrichment, and social isolation impose negative behavioral and physiological responses. Earlier studies confirm that rats prefer a cage with a shelter, but such enrichment is challenging due to the risk of interference with the quantitative collection of faeces and urine. In nitrogen metabolism studies, there is an increased risk of N-loss via ammonia emission if urea in the collected urine is not trapped and acidified.
In this project, we will investigate if metabolism cages enriched with shelters can improve the animal welfare and be employed without interference with the quality of the quantitative data. Such data are important in order to implement improvement in nutritional and biomedical studies involving housing of experimental animals in metabolic cages.