Effects of low, adequate and high dietary zinc intake on metabolic interactions between zinc, copper and iron in different mongolian gerbil tissues

Abstract

This study examined the influence of low, adequate and high dietary zinc intake on the growth and metabolic interactions between zinc, copper and iron in different Mongolian gerbil (Meriones unguiculatus) tissues. Animals were fed a basal diet (for 3 wk) containing a low-zinc level (8 mg/ kg diet, LZ-group), adequate zinc level (25 mg/kg diet, AZ-group) and saturated zinc level (38 mg/ kg diet, SZ-group). After comparing the body weight of gerbils, the present study demonstrated that the LZ-group (51.68 g +/- 3.35) showed growth retardation, contrary to the AZ- and SZ-groups (58.03 g +/- 2.18 and 62.35 g +/- 2.04, respectively). Concentrations of zinc in the liver, kidneys and testes in the LZ-group (41.28, 19.58, 22.55 mg/kg, respectively) were significantly lower than in the AZ-group (57.27, 23.73, 28.79 mg/kg, respectively) and the SZ-group (73.06, 30.07, 34.52 mg/kg, respectively). Results also showed that copper and iron concentrations in the kidney, heart and liver were significantly higher in the LZ-group (Cu 11.45, 7.01, 7.95 mg/kg; Fe 116.19, 126.07, 299.47 mg/kg) than in the AZ-group (Cu 8.72, 5.6, 6.5 mg/kg; Fe 97.27, 97.27, 250.25 mg/kg) and the SZ-group (Cu 6.48, 4.15, 4.8 mg/kg; Fe 74.95, 77.95, 200.27 mg/kg). There was an increase of testis copper concentration in the LZ-group (4.9 mg/kg) compared to the AZ- and SZ-groups (3.99 and 3.05 mg/kg, respectively), and there was no significant difference in testis iron concentration between animals in different diet groups. These results showed that a low-zinc diet had negative effects on growth and the concentration of zinc in the kidneys, liver and testes. This also affected homeostasis of copper and iron by increasing its distribution in the kidneys, liver and heart tissue. However, in testes only copper concentration was increased.