Increased intake of oil in obese OLETF rat is driven by caloric deficit.

Abstract

CCK-1 receptor-deficient Otsuka Long-Evans Tokushima Fatty (OLETF) rats are hyperphagic, become obese and diabetic. Also, they have an increased sham intake and enhanced preference for sucrose solutions relative to control, Long-Evans Tokushima Otsuka (LETO) rats. To determine the effects of oil on ingestion, we first measured real feeding of various concentrations of oil emulsions (12.5%, 25%, 50%, 75%, 100%) in rats that were food deprived overnight or non-deprived. OLETF rats consumed more corn oil than LETO in both feeding conditions, however, the strain difference was greater in the deprived compared to non-deprived. To assess the orosensory effects of oils as a function of caloric deprivation, sham feeding of 100% corn or mineral oil was measured in food deprived and non-deprived animals. Under deprived condition, OLETF sham fed more corn oil that LETO, and more corn than mineral oil. No differences in mineral oil intake were noted between strains. When non-deprived, OLETF's sham intakes were lower than under deprived condition. However, there were no significant differences in either corn or mineral oil intakes between strains. In a 2-botle sham feeding preference tests, food-deprived OLETF preferred corn more than mineral oil while LETO's preference was equal for both oils. In non-deprived condition, OLETF and LETO preferred both oils equally, however, mineral oil was less preferred than corn oil. These results show that increased oil intake in OLETF is primarily calorically driven. Supported by DK065709.