The effects of switching light-dark regime on the behavior of Wistar rats.

Abstract

Most living beings have a circadian rhythm that spans about 24 hours. Rodents are nocturnal animals, which means they are active during nighttime when there is no or little light present. Therefore, when evaluating behavioral aspects of nocturnal animals, this should preferably be done during the dark-phase. The goal of this research is to determine how this light-dark switch has an effect on the behavior of laboratory Wistar Unilever rats, and to determine the time needed for acclimatization. Overall we can state that transport itself had a clear effect on animals. Both reversal and control groups display a significant increase of resting behavior in week 1 comparing to week -1. Autogrooming shows an increase in the first week after transport in both the control groups, and there does seem to be a higher amount of autogrooming overall in both control groups. The amount of eating behavior clearly decreases during the first week in both reversal groups however this is not the case in the control groups. Playing and social behavior are both very variable during the entire experiment. In the male groups there is a decrease of playing and social behavior during the first week after transport however in the female groups this is not the case. When looking at active behavior we see that both the control and reversal groups display a decrease in week 1 in comparison to week -1. Here again the control groups also seem to be affected by the transport itself. We can conclude that it may be preferred to keep nocturnal animals in a reversed day-night cycle so that they won’t be disturbed during their resting period, however this requires more research.