The effects of feeding a zinc-deficient diet on taste acuity and tongue epithelium in rats.

Taste preferences, fluid intake and histology of tongue epithelium were studied in rats fed a zinc-deficient diet and in pair-fed controls. The results of two-bottle preference tests demonstrated that zinc-deficient rats exhibited significantly increased preferences for 1.5 X 10(-1) M HCL and 1.28 X 10(-6) M quinine sulfate as well as a significant increase in relative fluid volume intake. Histologic examination of the tongue epithelium of the zinc-deficient rats showed a hypercellular prickle cell layer and a marked parakeratosis. The fungiform papillae of the zinc-deficient rats exhibited acanthosis and mild parakeratosis. However, the pore region of the taste buds did not seem to be covered by the parakeratotic epithelium. The results suggest that the impaired taste observed in zinc-deficient rats may not be related to blockage of tastants from the pore region.