Single gene effect on alcohol preference in the Zucker rats

Zucker obese (ZO), Zucker lean (ZL), and Sprague-Dawley (SD) naive rats of both sexes were used to study the role of the fa/fa gene on alcohol preference. During the first two weeks of this experiment (weeks 1-2) all rats received a 10% alcohol solution ad lib as the only source of liquid. Animals were then given free access to both water and alcohol for the following three weeks (weeks 3-5). Thereafter, rats were deprived of alcohol every other day for two weeks (weeks 6-7), then completely deprived of alcohol for one week (week 8). Finally, unlimited access to both water and alcohol solution was available for the last two weeks of the experiment (weeks 9-10). Results of this study show that when rats were offered both water and alcohol (weeks 3-5), ZL rats consumed significantly more alcohol (2.5-fold) than their littermates, the ZO rats and the SD rats. Similarly, during alternate days of alcohol deprivation (weeks 6-7), ZL rats consumed significantly more alcohol (threefold) than the ZO rats and the SD rats. After a week of alcohol deprivation (week 8), and during the final two weeks (weeks 9 and 10), ZL rats continued to consume significantly more alcohol (2.5-fold) than the ZO group or the SD group. ZL females consumed more alcohol per kg body weight than male ZL rats. Data obtained from this study suggest that in the Zucker rat a single gene can alter the animal alcohol preference.