Decreased preference for sucrose in rats fed a low protein diet and its intensification by zinc-deficiency

This study examined whether protein concentrations in the diet of rats fed adequate Zn or deficient Zn affect their preference for disaccharides of sucrose and maltose. Sucrose and maltose were used as a source of carbohydrate and the selection patterns of rats were analyzed for 28 d by a two-choice selection method. Diets provided as a set of two either Zn-adequate or Zn-deficient diets containing 10, 20 and 40% protein each were changed in position daily. For the first 24 h, both the control Zn-adequate and Zn-deficient rats preferred sucrose to maltose and then gradually selected the maltose diet. Protein in the diet affected the selection of the disaccharides for both the control and Zn-deficient rats. The decrease order of the ratio of consumed sucrose to maltose over 28 d was 10% > 20% > 40% protein diet group, and Zn-deficiency emphasized the decrease. These results suggest that sucrose has a stronger taste effect than maltose in rats, but that the selection of sucrose is decreased by the post-ingestive effect which is stimulated in low-protein and Zn-deficient diets.