Copper hydroxychloride is more efficacious than copper sulfate in improving broiler chicken's growth performance, both at nutritional and growth-promoting levels

This study was designed to compare the effects of nutritional and growth-promoting levels of copper hydroxychloride (CH) with copper sulfate (CuSO₄) on growth, carcass characteristics, tibia traits and mineral concentration in broilers fed a conventional wheat-soybean meal–based diet. Day-old Ross 308 male chicks (n = 864) were randomly assigned into 8 dietary treatments with 6 replicates of 18 chicks per treatment. The dietary treatments included a basal diet containing no supplemental copper (Cu) serving as the negative control (NC); basal diet supplemented with 15 or 200 mg/kg Cu as CuSO₄; basal diet supplemented with either 15, 50, 100, 150, or 200 mg/kg Cu from CH. Diets were fed over the starter (day 1–14) and grower (day 14–35) phases. Birds in the NC group gained the same body weight and had similar feed conversion ratio (FCR) to birds receiving 15 mg/kg Cu as CuSO₄, but birds receiving 15 mg/kg Cu as CH had a lower FCR than the NC birds (day 0–35; P < 0.05). Birds fed 200 mg/kg Cu as CH gained more weight (77 g/bird) and had a lower FCR (3.2 point) compared with those fed 200 mg/kg Cu as CuSO₄ (P < 0.01). Based on broken-line regression models, the optimum inclusion level of Cu as CH in the diet for optimal body weight gain and FCR were estimated to be 109.5 and 72.3 mg/kg, respectively (P < 0.001). Carcass characteristics were not affected by dietary Cu sources or levels (P > 0.05). The highest and lowest tibia ash content were observed in birds fed diet with 150 mg/kg Cu as CH and 200 mg/kg Cu as CuSO₄, respectively (P < 0.05). Supplementation with 200 mg/kg Cu as CH resulted in higher duodenal mucosa Cu content compared with the diet containing 200 mg/kg Cu as CuSO₄ (P < 0.001). In conclusion, supplementation of Cu from CH was more efficacious than CuSO₄ in promoting growth performance, both at nutritional and pharmacological levels.