Necessity of an Acclimatization Period in a Home Cage Experiment of Mice

ObjectiveTo investigate whether an acclimatization period should be introduced into the home cage experiment for the detection of metabolic function in mice, and how to judge and set its length.MethodsData from 31 home cage experiments in 2016-2017 were collected, and each experiment was set up with a 3-day (72 hours) acclimatization period. Data such as water consumption, food intake, heat production, and body weight were recorded. The data were analyzed using 24-hour interval analysis to determine the acclimatization effect.ResultsApproximately 12% of the 356 mice drank less than 1 mL at the end of 96 hours. There were significant differences in water consumption, food intake, heat production rate, and body weight between 24-48 hours and 48-72 hours, but no significant differences were detected between 48-72 hours and 72-96 hours, except in food intake. Independent verification of the food intake of each experiment showed that there was a significant correlation between food intake adaptability and weight.ConclusionApproximately 12% of the mice were unable to learn or adapt to the new water bottle after the 72-hour acclimatization period, therefore, researchers should consider increasing the sample size of the experiment to eliminate invalid data. If food intake is not the focus of a study, the 48-hour acclimatization is sufficient to obtain reliable results.