Gustatory responsiveness to food-associated saccharides in European rabbits, Oryctolagus cuniculus

Taste preference thresholds for six food-associated saccharides and relative sweet-taste preferences were assessed in 12 European rabbits using two-bottle choice tests of brief duration (3 min). In Experiment 1, the animals were found to significantly prefer concentrations as low as 30 mM maltose, 50 mM polycose and sucrose, 75 mM glucose, 150 mM fructose, and 175 mM lactose over tap water. In Experiment 2, the rabbits were given a choice between all binary combinations of the same six saccharides presented in equimolar concentrations of 100 and 200 mM. Preferences for individual saccharides were stable across the concentrations tested and indicate the following order of relative effectiveness: maltose=polycose>sucrose>glucose>fructose > or =lactose. The results showed rabbits to display a pattern of taste preference thresholds and relative taste preferences for food-associated saccharides similar to that found in rodents but differing markedly from that found in human and nonhuman primates. The results support the assumptions that rabbits, unlike most primates, but similar to rodents, may have specialized taste receptors for starch, and that the gustatory responsiveness of Oryctolagus cuniculus to food-associated saccharides might reflect an evolutionary adaptation to its dietary habits.