Effects of replacing a dietary antibacterial agent (zinc bacitracin) with copper salts in Cherry Valley Pekin meat ducks

1. A study was conducted to investigate the effectiveness of high dietary copper concentrations obtained from tribasic copper chloride (TBCC, 58% copper) and copper sulphate pentahydrate (CuSO4, 25% copper) in replacing antibiotic growth promoters (AGP) in duck diets. 2. A total of 960 one-day-old Cherry Valley meat-strain ducks were divided into 3 treatment groups, with 8 replicates per treatment, in a 6-week feeding trial. The ducks were fed a basal diet supplemented with AGP (40mg zinc bacitracin/kg and 40mg garlicin/kg of diet) or 150mg of Cu/kg of diet, given as either CuSO4 or TBCC. 3. The body weight, average daily gain, average daily feed intake and mortality of ducks were not affected by the dietary treatments. However, the feed/gain ratio of ducks that were fed TBCC diets was significantly lower than those of ducks that were fed CuSO4 diets and were similar to those in the AGP group. 4. TBCC increased the Cu content in the liver tissue of ducks compared with the content in those that were fed the diet supplemented with AGP. TBCC also increased the Fe and Zn content in breast muscles compared with that in ducks that were fed the diet supplemented with CuSO4. 5. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were significantly higher in the serum of ducks that received the diet supplemented with TBCC than AGP or CuSO4. TBCC treatment decreased the malondialdehyde (MDA) content in serum of ducks compared with groups supplemented with CuSO4. 6. No significant difference was observed in liver or muscle fat content among the different dietary treatment groups. The serum low-density lipoprotein cholesterol concentration was lower in ducks fed AGP diets than those fed CuSO4 diets. 7. It was concluded that the replacement of AGP with 150mg of Cu/kg of feed from TBCC improved the feed efficiency, trace mineral deposition and antioxidant status more than when the source of copper was CuSO4.