Acclimatisation of rats before scientific experiments

Abstract: The most common laboratory animals in Sweden today are mice, rats, and zebrafish. We sent out an anonymous digital survey to investigate if scientific facilities in Sweden acclimatise their rats after transportation, how long the acclimatisation time is, and how the acclimatisation is conducted. Studies have been made showing the effect transportation may have on rats. They have measured parameters such as corticosterone levels, heart rate, blood pressure, and behavioural changes. However, the recommendations given vary between 3 days and up to 2 weeks. Studies have also shown differences in acclimatisation times between females and males; where females will need longer for corticosterone levels to return to concentrations close to that before transportation. Results from the conducted survey showed that a majority of research facilities acclimatise the rats after transport from the breeder; however, the acclimatisation times between facilities vary. Approximately 50% of the facilities acclimatise the rats for less than 7 days. Results from the survey also showed that a majority base the length of the acclimatisation time on experience/recommenda-tions or that their main focus and base for the acclimatisation time was to reduce stress. Only a small percentage based the acclimatisation time on legislation or scientific studies. This may be due to the fact that neither European nor Swedish regulations on laboratory animals contain information and guidelines as to how long an appropriate acclimatisation time should be. It’s been proven that stress can have an effect on scientific results. This would constitute the importance of accurate acclimatisation before the experiment. More studies are needed on the subject in order to help and guide laboratory personnel to apply an accurate acclimatisation time catered to the individual group of rats used.