This study was conducted to determine the effects of arginine (Arg) supplementation on reproductive performance, immune response and antioxidant status in breeder quails reared under heat stress (HS). Atotal of 125 breeder quails were divided into five groups. One group was kept in an environmentally controlled room (22 °C) and considered as thermoneutral and four groups were kept at 34 °C and fed a basal diet or a basal diet supplemented with Arg concentrations 1.15, 1.30 and 1.45 times the quail requirements per NRC recommendation. HS decreased performance in birds fed basal diet (p < .05) compared with thermoneutral group. Higher feed intake and egg production, and improved feed efficiency and Hugh unit variables occurredin Arg supplemented groups (p < .05). Birds receiving Arg under HS had higher maternal serum IgG, egg yolkIgY and offspring serum IgG (mg/ml) indicating that the Arg in the diets significantly influenced the immune response of birds. Also, improved in humoral and cell-mediated immune responses occurred in Arg supplemented groups. Quails receiving the Arg supplemented diets exhibited higher (p < .05) plasma and liver activity of superoxide dismutase, catalase and glutathione peroxidase as well as lower (p < .05) plasma andliver levels of malondialdehyde compared with the HS group fed the basal diet. Our results show that dietary supplementation with Arg could improve the performance of breeder quails under HS by reducing the negative effects of HS, thus could be considered as a nutritional strategy to alleviate the adverse effects of HS.
