Dietary arginine supplementation enhances the growth performance and immune status of broiler chickens

This experiment was conducted to investigate the effects of dietary Arg on growth performance and immunity in broiler chickens. Three hundred 1-d-old broiler chickens were divided into 5 treatments with 6 cages and 10 chickens per cage. The broiler chickens in the 5 treatments were fed with the basal diet (Arg-deficient diet, 8.6% Arg in diet from 0 to 21 d and 6.8% Arg in diet from 21 to 42 d) supplemented with 0%, 0.45%, 0.90%, 1.35%, and 1.80% Arg, respectively. The effects of dietary Arg on performance and immune status were assessed. The results showed that, with increasing of dietary Arg content, body weight was increased quadratically on d 21 (P < 0.01) and 42 (P < 0.01). The daily weight gain (P < 0.01) and feed conversion (P < 0.05) were improved quadratically during the entire period. In addition, with increasing of dietary Arg content, serum concentrations of growth hormone (P < 0.01), insulin-like growth factors-1 (P < 0.01), insulin (P < 0.01), IgA (P < 0.01), and IFN-γ (P < 0.01), as well as thymus weight (P < 0.05) of broiler chickens, were improved quadratically on d 21; and lymphocyte proliferation (P < 0.01), the antibody titers to newcastle disease (linear, P < 0.01; quadratic, P < 0.01), and serum IgM concentration (P < 0.05) were increased linearly or quadratically on d 42. The results indicated that incorporating Arg in excess of the 1994 NRC requirement improves the growth and immunity of broiler chickens.