Diet self-selection and food hoarding after food deprivation by Siberian hamsters

Siberian hamsters (Phodopus sungorus) increase food hoarding, but not food intake, after a fast. Because the physiological mechanisms underlying these changes in food hoarding are virtually unknown, we sought insight into the se mechanisms by allowing hamsters to self-select their diet from food sour ces varying in macronutrient composition and caloric density("dietary wisdo m"). Therefore, the effects of food deprivation length on diet self-selecti on were tested in adult female hamsters after adaptation to three composite diets: sunflower seeds (SS), pellet chow (PC), and rabbit chow (RC). One g roup initially was fasted for 32 h, the other for 56 h, and then each was r efed. The remaining nonexperienced fast was instated after prefast body mas s, food intake, and hoarding were recovered. Food hoarding, but not food in take, was increased regardless of fast length or sequence; moreover, the la rgest increase in food hoarding was on the first day of refeeding and was p rimarily reflected as increased SS hoarding. When the longer fast occurred first body mass loss was greater and the increased food hoard size was main tained for more days than when the longer fast came second. The order of fo od intake and hoarding preferences was not changed after a fast (SS > PC > RC), but the degree of food hoarding preference for SS was exaggerated. Col lectively, these results support the notion that food hoarding increases wi th decreases in lipid stores, and show that when internal lipid stores are decreased, external lipid stores are preferentially increased. (C) 1999 Els evier Science Inc. All rights reserved.