Evidence for genetic determination of specific food choices of rats

To study the contributions of genetics to food selection in an omnivorous species, rats of two strains and rats derived from reciprocal crosses of the two strains were compared. In addition, offspring of rats that accepted a specific food (ham) were compared with offspring of rats that refused the same food, and food selection of males was compared with that of females. Both homozygous nonobese Zucker rats and Zucker x Sprague-Dawley hybrid rats ate butterscotch, semisweet chocolate, and ground beef more often than Sprague-Dawley rats did. In contrast, Zucker rats ate ham more often than hybrid rats did, and hybrid rats in turn ate ham more often than Sprague-Dawley rats did. Rats produced by the two reciprocal crosses were similar to each other in food selection, ruling out maternal environment effects as the explanation for differences between Zucker and Sprague-Dawley rats. Hybrid rats selected for rejecting ham produced offspring that ate ham less often than did offspring of rats that accepted ham. Females ate semisweet chocolate more often than males did. We conclude that, contrary to the widely accepted view, heredity significantly influences specific food choices in an omnivorous species.