The study was conducted on 300 turkey cocks type BUT-9, grown under optimal conditions for this kind of poultry. The feed was a typical commercial full-dose mix for turkeys.The birds were divided into 5 experimental groups. From the 3rd week of their life,they were given preparations with their drinking water. Group I was the control group,while drinking water for the test groups was enriched as follows: lactic acid (0.4%) for group II, CuSO4  in the amount of 30 mg Cu⋅dm–3 H2O for group III, CuSO4 (30 mg Cu⋅dm–3) and 0.4% of lactic acid for group IV and CuSO4 in the amount of 50 mg Cu⋅dm–3 for group V. Application of the preparations was terminated after 3 days, when symptoms of poisoning were observed in turkey cocks of groups II and IV, alongside increased mortality rate. Samples of drinking water were taken for analyses, and from each group 10 birds were selected for slaughter to take tissue samples (breast and leg muscles). The objective of the experiments was to determine the concentration of Ca, Mg, Zn, Cu and Fe in the consumable tissues of turkey cocks.The study showed that the highest rate of mortality of turkey cocks was observed inthe group that was given lactic acid with their drinking water, and these turkeys had increased levels of Ca, Cu, Zn and Fe. In none of the groups, the content of Zn in the breast muscle exceeded 20 mg kg–1, while the concentration of copper in all experimental groups (except the control) was above the level of 10 mg kg–1. Increased doses of copper caused an increase in the concentration of magnesium in the leg muscles, while a combination of copper supplementation with lactic acid resulted in increased accumulation of Cuin both the breast and leg muscles.