Fat and sugar flavor preference and acceptance in C57BL/6J and 129 mice: experience attenuates strain differences.

C57BL/6J (B6) mice display stronger preference and acceptance for various sweeteners than do 129 mice (129P3/J, 129X1/SvJ). The present experiment compared the preference of these strains for fat flavor as well as sweet taste using 24-h two-bottle preference tests. Fat flavor preference was evaluated using non-nutritive (olestra) and nutritive (Intralipid) oil emulsions. In initial oil vs. water tests olestra preference and intake were greater in B6 mice than 129 mice. Similar strain differences were obtained with low (0.313%-5%) but not high (10%-20%) Intralipid concentrations. When retested with Intralipid the B6 and 129 mice showed strong (>90%) preferences for the nutritive oil although B6 mice still consumed more oil at low concentrations. A second olestra test revealed increased oil preference and acceptance in B6 and 129X1/SvJ mice while 129P3/J mice still did not prefer olestra to water. Sweetener tests revealed stronger saccharin and sucrose preferences in B6 mice than in 129 mice. These strain differences in sweetener preference disappeared when the mice were retested with sucrose and saccharin. However, B6 mice continued to consume more saccharin and sucrose (at low concentrations) than did 129 mice. The profile of strain differences for non-nutritive and nutritive oils was similar to those observed for non-nutritive and nutritive sweeteners. The differential sweetener preferences of B6 and 129 mice is explained by differences in their sweet taste receptors but why the strains also differ in their initial fat flavor preference is not clear. The experientially-induced increases in oil and sweetener preferences displayed by the mice are attributed to the post-oral actions of Intralipid and sucrose. These findings along with intragastric infusion data suggest that B6 and 129 mice differ in their oral but not their post-oral response to fat and sugar.