The research was done on 45 animals (young pigs) that were divided in 3 variants: V1 = 6 mg Cu / kg fooder; V2 = 31.25 mg Cu / kg fooder (CuSO4 + 5 H2O); V3 = 31.25 mg Cu / kg fooder (Cu - polyphosphate glass source). The duration of the trial was 60 days. In the growth period the average daily gain was significantly increased (p≤0.05) to V2 (369 g/ day) and V3 (394 g / day) comparative with V1 (321 g / day). fooder conversion ration was significantly lower to V2 (2.54 kg) and V3 (2.37 kg) than V1 (2.81 kg).