Effect of vitamin C supplementation on performance, immune response and antioxidant status of heat stressed White Leghorn layers

An experiment was conducted to evaluate the performance, immune response and antioxidant status of commercial White Leghorn (WL) layers fed diet supplemented with vitamin C (0, 200, 400 or 600 mg/kg diet) during summer (30 – 44°C). Vitamin C supplementation (200 mg/kg diet) significantly improved egg production, feed efficiency, egg shell weight and shell thickness, and concentrations of serum calcium and protein in heat stressed layers. No further benefits could be noticed by enhancing the levels of supplementation to either 400 or 600 mg/kg diet. Body weight gain, egg weight, daily feed consumption, egg specific gravity, shell breaking strength, Haugh unit and serum phosphorus concentration were not influenced by vitamin C supplementation. Supplementation of vitamin C significantly reduced the activity of lipid peroxidase and increased the activity of catalase. Highest concentration of catalase and lowest concentration of lipid peroxidase was observed in the dietary group supplemented with 400 and 600 mg vitamin C per kg diet, respectively. The antibody titre in response to SRBC inoculation increased significantly by supplementation of vitamin C (200 mg/kg diet). It is concluded that dietary supplementation of vitamin C (200 mg/kg) improved egg production and egg shell quality, humoral immune response and antioxidant status in White Leghorn layer during summer stress.