Zinc's Role in Rat Preference for a Low-Fat Diet in a Two-Choice Diet Program of Low- and High-Fat Diets

摘要

To investigate the change in preference for a low-fat diet (LFD) and a high-fat diet (HFD) under disorders induced by a zinc (Zn)-deficiency, two groups of 4-wk-old male rats were fed a two-choice diet of Zn-deficient (ZnD; 0.75 mg/kg) and Zn-adequate (ZnA; 30.75 mg/kg) LFD and HFD. After 21 d, 10 rats in each of the two groups were sacrificed. The remaining ZnD rats were switched to ZnA diets for 7 d. Intakes of the LFD and the HFD were measured to determine the diet preferences of the ZnD, the ZnA and the Zn-recovered groups. Energy intake of the ZnD group was significantly lower than that of the ZnA group and showed cyclical 3- to 4-d patterns of decrease. In the ZnD group, although the LFD intake decreased parallel to the reduction in the energy intake, the HFD intake did not show the cyclical pattern of decrease. The reduced intake of the LFD in the ZnD rats was accompanied by a low carbohydrate intake and a low plasma insulin concentration. When the ZnD group recovered sufficient amounts of Zn, the energy intake was restored to normal levels and the difference in the LFD intake and the plasma insulin concentration disappeared between the ZnD and the ZnA groups. It was supposed that the specific change in the LFD intake patterns during development and recovery from Zn-deficiency might be related to Zn-mediated changes in impaired synthesis and the release of insulin from the pancreas.