The experimental production of zinc deficiency in the rat.

I . Techniques for the preparation of a semi-synthetic basal diet suitable for the rapid production of zinc deficiency in the rat are described. The complete diet usually contains between 0.6 and 0.9 ppm Zn. 2. When the unsupplemented diet was fed to weanling rats, growth arrest occurred after 4-5 d ; when supplemented with ZnSO., to provide 12 or 20 ppm Zn, the rate of growth of rats was similar to that attained in animals given a conventional stock colony diet providing 83 ppm Zn. A study of relationships between dietary Zn concentration and weight gain in 21 d suggested that the Zn requirement of male and female rats for growth on this diet is approximately IZ ppm. 3. The development of Zn deficiency on diets providing < I or 3 ppm Zn was accompanied by poor food consumption and the development of a characteristic cyclic pattern of intake. A significant decline in the variability of daily food intake was observed when the diet was supplemented with Zn to provide 6 , 9 or 12 ppm. 4. Studies of the influence of dietary Zn content upon changes in the Zn content of a range of tissues and upon whole-body Zn retention are reported. 5. The above findings are discussed in relation to the problem of defining the severity and duration of Zn deficiency in animals used for studies on the nature of the metabolic role of Zn.