A 42-day experiment was conducted to evaluate the influence of dietary copper (Cu) concentrations on growth performance, nutrient digestibility, and serum parameters in broilers aged from 1 to 42 days. Five hundred forty 1-day-old broilers were randomly assigned into 1 of the following 6 dietary treatments: (1) control (basal diet without supplemental Cu), (2) 15 mg/kg supplemental Cu (Cu15), (3) 30 mg/kg supplemental Cu (Cu30), (4) 60 mg/kg supplemental Cu (Cu60), (5) 120 mg/kg supplemental Cu (Cu120), and (6) 240 mg/kg supplemental Cu (Cu240), Cu as copper methionine. A 4-day metabolism trial was conducted during the last week of the experiment feeding. The results showed that dietary Cu supplementation increased the average daily gain and the average daily feed intake (P < 0.01). The feed gain ratio, however, was not affected by dietary Cu (P > 0.10). Additionally, dietary Cu supplementation increased the digestibility of fat and energy (P < 0.05). The concentration of serum cholesterol, triglycerides, and high-density lipoprotein cholesterol decreased with dietary Cu supplementation (P < 0.05). The activities of serum Cu-Zn superoxide dismutase (P < 0.05), glutathione peroxidase (P < 0.05), and ceruloplasmin (P = 0.09), on the contrary, were increased by Cu addition. For immune indexes, dietary Cu supplementation increased serum IgA and IgM (P < 0.05). In addition, the activities of serum ALT increased with increasing dietary Cu supplementation (P < 0.05). In conclusion, our data suggest that Cu supplementation can increase fat digestibility and promote growth. Additionally, dietary Cu supplementation can reduce serum cholesterol and enhance antioxidant capacity in broilers.
Keywords: Antioxidant defenses; Broilers; Copper; Growth performance; Lipid profiles; Nutrient digestibility.