Reduced Growth and Skeletal Changes in Zinc-Deficient Growing Rats Are Due to Impaired Growth Plate Activity and Inanition

Abstract

We investigated the effects of dietary zinc deficiency on skeletal metabolism in an animal model. Thirty 21-d-old male Sprague-Dawley rats were fed for 28 d either a zinc-deficient (ZD) diet (1 mg zinc/kg) or a normal diet ad libitum (AL, 50 mg zinc/kg) or in the same quantity as the ZD (pair-fed, PF). Only in the ZD group were general physical signs of zinc deficiency observed. Compared with the AL and PF rats, ZD rats showed significantly lower mean values in ponderal growth rate, femur weight and length, circulating levels of insulin-like growth factor-I, bone mechanical properties and concentration of zinc and, on histomorphometry, a decrease in the thicknesses of the overall growth plate and hypertrophic cartilage. In contrast, although bone volume was significantly lower in the ZD and PF rats than in the AL rats, no difference was observed between the ZD and PF rats. Osteoclast surface/bone surface and osteoclast number/bone surface ratios were significantly greater in PF rats than in the other two groups and not different in ZD and AL rats. Collectively, these data indicate that zinc deficiency has profound effects on the skeletal system of growing rats. In particular, the effects of zinc deficiency on bone growth and mass are the result of the reduced activity of the growth plate, likely mediated by impairment in the insulin-like growth factor-I system. We did not demonstrate an effect on bone mass via increased bone resorption.

The effect of zinc and manganese source in the diet for laying hens on eggshell and bones quality

“…Leach and Gross (1983) reported, that eggshells from hens fed Mn deficient diet are thinner and show alterations in eggshell ultra structure in mammillary layer and decreased content of hexozamine and hexuronic acid in the organic matrix. There is a lack of literature data on the effect of dietary Zn and Mn on the bone quality in laying hens, but Zn deficiency negatively affected skeletal metabolism in young chickens (Wang et al, 2002) and growing rats (Ovesen et al, 2001;Rossi et al, 2001). …”

Effect of in Utero Cadmium and/or Zinc Exposure on Occurrence of Squeletal Abnormalities.

“…In fact, studies examining effects of Zn deficiency in animal models have shown that mild to severe Zn deficiency disturbs skeletal growth and maturation (Eberle et al, 1999;Wang et al, 2002). Animals fed on Zn-deficient diets have impairment in growth plate chondrocyte proliferation (Rossi et al, 2001;Wang et al, 2002) and bone mass (Eberle et al, 1999). Bone formation in Zn-deficient animals is also characterized by retarded growth plate activity and is associated with reduced cancellous and trabecular volume (Oner et al, 1984;Rossi et al, 2001).…”

“…Animals fed on Zn-deficient diets have impairment in growth plate chondrocyte proliferation (Rossi et al, 2001;Wang et al, 2002) and bone mass (Eberle et al, 1999). Bone formation in Zn-deficient animals is also characterized by retarded growth plate activity and is associated with reduced cancellous and trabecular volume (Oner et al, 1984;Rossi et al, 2001). …”

Dietary zinc may attenuate heat-induced testicular oxidative stress in mice via up-regulation of Cu-Zn SOD

“…Mice in heat group were housed under control group conditions, but additionally subjected to 40°C and 50 ± 5% RH between 12 and 2 p.m. daily, for eight consecutive days during heat treatment period. The whole body heat temperature of 40°C for 2 h was selected on the basis of previous reports of total recovery after heat treatment and feasible parameters for a chronic heat model in mice (Rossi et al, 2001;Li et al, 2013). Following heat treatment each day, feed weight (as a measure of feed intake) and body weights were of all mice were recorded.…”

“…Zinc has also been found to be an indispensable element in reproduction and is required for the maintenance of germ cells; progression of spermatogenesis; and, regulation of sperm motility (Zhao et al, 2011). The effects of Zn deficiency are similar in most animal species and include dermatitis, alopecia, ocular lesions, testicular atrophy, growth retardation, and anorexia (Rossi et al, 2001). Zinc deficiency in male reproduction results in gonad dysfunction, decreased testicular weight, and seminiferous tubule shrinkage (Bedwal and Bahuguna, 1994).…”