Fat preference and acceptance in the CD36 knockout mice.

Abstract

CD36 is a membrane fatty-acid binding protein found in taste cells as well as enterocytes and is hypothesized to mediate “fatty” taste in rodents. This is supported by the report that CD36 knockout (KO) mice, unlike wild-type (WT) mice, fail to prefer 2% linoleic acid (LA). The present study further examined fat preference in KO mice given 24 h/day choice tests with nutritive (soybean oil, LA) and non-nutritive (olestra) oils. In Experiment 1 KO mice initially showed little or no preference for olestra (0.313–2.5%) or soybean oil (0.313–1.25%) but at higher concentrations (2.5–20%) they developed soybean oil preferences similar to WT mice. In subsequent tests, the KO mice, like WT mice, also preferred 2% LA and 2% olestra. In Experiment 2, naive KO mice failed to prefer 2% LA but after experience with soybean oil (0.0025–16%) displayed a preference similar to WT mice (77 vs. 79%). The KO mice showed a strong preference (>90%) for soybean oil (2–16%) although they consumed less oil than WT mice. In Experiment 3, KO mice displayed a strong conditioned preference, but reduced acceptance for a sweet flavor paired with intragastric infusion of 5% soybean oil. Thus, CD36 may mediate the preference for dilute oil but other orosensory (texture) stimuli and post-oral conditioning can support fat preferences at higher concentrations. CD36 KO mice may consume less oil than WT mice because of postingestive effects as a result of delayed fat absorption in the gut. Supported by DK031135, DK033301, DK060022.