The orosensory recognition of long-chain fatty acids in rats

To determine the selectivity of long-chain fatty acid (LCFA) in the oral ca vity, short-term (5 min) two-bottle tests were conducted in rats. Fifteen m ale Wistar rats were given oleic acid, linoleic acid, linolenic acid, and t heir derivatives. All compounds used were 99% pure. The concentration of te st fluids was made 1% in 0.3% xanthan gum to minimize postingestive and tex tural effects. The rats preferred LCFA fluids to the control of 0.3% xantha n gum solution. The preference order of LCFA was linolenic acid > linoleic acid > oleic acid. Four LCFA derivatives (methyl oleate, oleyl alcohol, met hyl linoleate, and linolyl alcohol), triolein, and capric acid were not pre ferred to LCFA, but LCFA derivatives were preferred to the control of xanth an gum solution. These studies suggest that rats select LCFA from olfactory or gustatory cues that are related to both the carbon chain and carboxylat e group. (C) 1999 Elsevier Science Inc.