Heike Vogel, Maria Kraemer, Cristina Rabasa, Kaisa Askevik, Roger A.H. Adan,Suzanne L. Dickson
Behavioural Brain Research, 328 (2017) 95-104
tHere we sought to define behavioural traits linked to anxiety, reward, and exploration in different strainsof rats commonly used in obesity research. We hypothesized that genetic variance may contributenot only to their metabolic phenotype (that is well documented) but also to the expression of thesebehavioural traits. Rat strains that differ in their susceptibility to develop an obese phenotype (Sprague-Dawley, Obese Prone, Obese Resistant, and Zucker rats) were exposed to a number of behavioural testsstarting at the age of 8 weeks. We found a similar phenotype in the obesity susceptible models, ObeseProne and Zucker rats, with a lower locomotor activity, exploratory activity, and higher level of anxiety-like behaviour in comparison to the leaner Obese Resistant strain. We did not find evidence that rat strainswith a genetic predisposition to obesity differed in their ability to experience reward from chocolate (ina condition place preference task). However, Zucker rats show higher motivated behaviour for sucrosecompared to Obese Resistant rats when the effort required to obtain palatable food is relatively low.Together our data demonstrate that rat strains that differ in their genetic predisposition to developobesity also differ in their performance in behavioural tests linked to anxiety, exploration, and rewardand that these differences are independent of body weight. We conclude that genetic variations whichdetermine body weight and the aforementioned behaviours co-exist but that future studies are requiredto identify whether (and which) common genes are involved.