Increased flavor preference and lick activity for sucrose and corn oil in SWR/J vs. AKR/J mice

Nutrient preferences and orosensory responses were characterized in two mouse inbred strains. In two-bottle solution tests (tastant vs. vehicle; ascending concentrations), the effects of strain and chow type (12 or 26% fat) on preference thresholds for sucrose and corn oil were compared in AKR/J and SWR/J mice. SWR/J mice displayed lower preference thresholds and ingested more sucrose than AKR/J mice did. SWR/J mice also showed lower preference thresholds and consumed more corn oil than AKR/J mice did; corn oil preference was suppressed 3.5-fold in AKR/J mice compared with SWR/J mice when fed 26% fat chow. Next, licking was recorded during 30-s access to sucrose or corn oil across a range of concentrations. SWR/J mice licked the tastants more than AKR/J mice did. Analysis of modal interlick intervals during lick training revealed that SWR/J mice licked water faster than AKR/J mice when water deprived, suggesting that motor as well as sensory factors may determine lick responses to tastants in brief-access tests. Finally, in two-bottle tests pitting maximally preferred concentrations of sucrose (8 or 16%) against corn oil (20%), SWR/J mice highly preferred sucrose over corn oil at either sucrose concentration. AKR/J mice preferred corn oil over 8% sucrose but reversed their preference when 16% sucrose was offered. These results support a primary role of flavor in the nutrient preferences of SWR/J mice. In AKR/J mice, the low lick activity for sucrose and corn oil and greater suppression of corn oil preference by the high-fat chow suggest that their preferences depend more on postingestive factors than on flavor.