Species differences in polysaccharide and sugar taste preferences.

This study compared the polysaccharide and sugar taste preferences of humans and four rodent species (laboratory rats, Rattus norvegicus; Golden Syrian hamsters, Mesocricetus auratus; Mongolian gerbils, Meriones unguiculatus; Egyptian spiny mice, Acomys cahirinus). In Experiment 1 human subjects rated the pleasantness, sweetness, and flavor intensity of polysaccharide (Polycose), sucrose, and maltose solutions at concentrations of 0.0125 M to 0.4 M, and 1% to 32% concentrations. At the higher molar concentrations Polycose was rated as less sweet and less pleasant than the sucrose and maltose solutions; there were no differences in the flavor intensity ratings. With the percent concentrations Polycose was rated as less sweet and less flavorable as the sucrose and maltose solutions; there were no reliable differences in the pleasantness ratings. In Experiment 2, the Polycose, sucrose, and maltose preferences of rats, hamsters, gerbils, and spiny mice were compared using 24 hr two-bottle tests (saccharide vs. water) at concentrations of 0.001 M, 0.005 M, 0.01 M, and 0.1 M. In general, the rats displayed stronger preferences for Polycose and maltose than did the other three species. In addition, the gerbils showed a stronger Polycose preference at the 0.1 M concentration than did the hamsters and spiny mice, and the spiny mice display a weaker preference for sucrose than did the other three species. Within species comparisons revealed that all four species displayed preferences for Polycose that were as strong or stronger than their preferences for sucrose and maltose. With only a few exceptions, male and female rodents did not differ in their saccharide preferences. Thus, while rats show the most robust Polycose preference of the four rodent species, all four species were attracted to the taste of polysaccharides. Humans, on the other hand, reported that Polycose solutions were unpleasant. The results suggest that rodents have taste receptors for starch-derived polysaccharides that humans lack.

Sex differences in polysaccharide and sugar preferences in rats.

The preferences of adult male and female rats for sucrose and polysaccharide (Polycose) solutions were measured in three experiments. In Experiment 1, male and female rats did not differ in their preference for molar solutions of sucrose or Polycose as measured by 24-hr solution vs. water tests. In Experiment 2, however, male rats displayed a greater preference for Polycose, and females a greater preference for sucrose as measured in 3-min and 30-min/day sucrose vs. Polycose tests. Both sexes preferred Polycose to sucrose at low concentrations, but switched their preference at higher concentrations. Experiment 3 revealed that both male and female rats strongly preferred 32% sucrose to 32% Polycose in 30-min/day two-solution tests, but this preference did not persist when the rats were given 24-hr/day access to the two solutions. Male rats lost their sucrose preference, while female rats developed a preference for Polycose over sucrose. The sexes also differed in that the female rats increased their total caloric intake more and consumed proportionately more carbohydrate than did the male rats during the 24-hr/day test. The findings demonstrate that while both male and female rats have an avid appetite for polysaccharide and sucrose solutions, they differ in their short-term and long-term relative preferences for the two carbohydrates, as well as in their caloric and diet selection responses to the carbohydrate solutions. The possible functional significance of these sex differences are discussed.