Growth and development in postnatally zinc-deprived mice

The influence of postnatal zinc deprivation upon the growth and development of outbred mice was investigated by feeding groups of animals, during the suckling period, one of four diets: 100 ppm zinc (control); 9 ppm zinc (marginal deficiency); 5 ppm zinc (moderate deficiency), and 2.5 ppm zinc (severe deficiency). In addition to control for inanition caused by zinc deprivation, a group of mice were fed the control diet but in amounts equal by weight to the measured intake of the moderately deprived animals (5 ppm zinc). A variety of developmental anomalies was observed in the zinc-deprived animals, including alopecia, extensive dermatitis, delayed opening of eyes and incoordination. Furthermore, growth in body weight and length were reduced. Similarly, on the basis of absolute net weight, heart, kidney and liver all demonstrated a significant stunting, and there was a direct relationship between the magnitude of organ growth retardation and the degree of zinc deprivation. However, when examined on a relative basis as a percentage of total body weight, only liver growth was significantly retarded. The heart and, most notably, the kidney represented an even greater proportion of body weight in the zinc-deprived mice than in the controls. We conclude that, in the mouse, the heart and kidney were affected to a lesser extent by zinc deficiency than was the whole animal. This observation is in contrast to the extreme lack of growth, but absolute and relative, of the spleen and especially the thymus, previously described by us in mice deficient in zinc during the suckling period.