Behavioral differences in three Wistar Han rat lines for emotional reactivity, cognitive processing and ethanol intake.

Many laboratories obtain their experimental animals from commercial suppliers and are therefore dependent on their conditions and breeding schedules. A breeding stop or the substitution of a particular rat line by the supplier forces the customers to abandon their conventional test animals and to re-establish all behavioral paradigms with a new rat line. Therefore, it is vital to know whether behavioral differences emerge in various breeding lines of the same rat strain. In a recent case, the commercial supplier Harlan Laboratories GmbH is substituting the previous HsdHan:WIST line of Wistar rats with the RccHan:WIST line descending from a different breeding stock. We therefore tested animals of both lines (RccHan:WIST and HsdHan:WIST from Harlan Laboratories GmbH) as well as Wistar rats of the same line but obtained from a different supplier (Janvier) in a broad range of behavioral paradigms. We observed differences in locomotor activity, in classical anxiety-related paradigms (elevated plus maze and light/dark emergence test), as well as in object recognition memory and prepulse inhibition (PPI) of the acoustic startle reflex (ASR). We also found differences in ethanol intake and preference, but not regarding the intake of a palatable food reward and a bitter solution (quinine). These results demonstrate considerable variations in the behavioral phenotype between different breeding lines of the same Wistar rat strain and aim to increase the awareness of behavioral scientists for line and supplier differences affecting animal behavior.