Effect of dietary supplemental vitamin C and zinc sulfate on productive performance, egg quality traits and blood parameters of laying hens reared under cold stress condition

This study was conducted to investigate the effects of dietary supplemental vitamin C and zinc sulfate on performance, egg quality characteristics and blood parameters of laying hens reared under cold stress condition. A total of 144 Lohmann-LSL Lite laying hens (65 weeks old) were allotted to 24 groups. Based on a 2 × 2 factorial arrangement, four corn-soybean-based diets (2750 kcal/kg ME and 14.69% CP) including two levels of vitamin C (0, 240 mg/kg) and two levels of zinc sulfate (0, 40 mg/kg) were assigned to hens with six replicate cages (n = 6) during 3-month experimental period. The data were analysed in a completely randomized design using GLM procedure of SAS. Increased egg weight (EW), egg mass (EM) and albumin weight egg and heterophil to lymphocyte ratio, and reduced FCR were observed in hens fed the zinc-included diet (P < 0.05). Supplementing the diet of laying hens, with zinc sulfate increased egg mass and improved FCR. Significant interaction between supplemental vitamin C and zinc sulfate was detected on egg Haugh unit and shell thickness, so that the best results were observed when the diet of laying hens was supplemented by 240 mg/kg vitamin C