The Effect of Zinc Oxide Nanoparticles on Production Performance, Egg Quality Traits and Antioxidant Status of Laying Hens

The aim of the present study was to evaluate the effect of zinc oxide on production performance, egg quality and antioxidant status of layer hens. This experiment was performed with 96 Bovens strain layer hens at peak production (28-35 weeks) in a completely randomized design with 3 treatments with 4 replicates and 8 hens each for 3 periods of 28 days. The treatments included control group (without zinc oxide nanoparticles) and two levels of 100 and 200 mg zinc oxide nanoparticles (ZnONPs) /kg of diet. Experimental diets were provided to laying hens for 8 weeks. Zinc oxide nanoparticles increased the egg mass (32-35 wk), and decreased feed intake (28-31wk) compared to control (P<0.05). The ZnONPs did not affect the egg production and egg weight. The haugh unit (31 and 35 wks) and quality traits of egg shell including eggshell stability (31 and 35 wks), and relative weight of eggshell and specific gravity (35wk) increased with increasing ZnONPs supplementation in diet (P<0.05). The concentration of total protein, HDL, and antibody against Newcastle disease were not affected by ZnONPs supplementation level. The use of ZnONPs supplementation reduced the concentration of cholesterol, triglyceride, LDL, concentration of MDA in blood and yolk, and the activity of the enzyme ALT (P<0.05). The ZnONPs supplementation increased the antibody titer against the influenza and increased zinc concentration in the blood. The results of this research showed that supplementation of 200 mg of ZnONPs per kg of layer diet may improve the growth performance indices, hough unit and egg shell quality, and decrease the blood lipids and improve immune response in layer hens at peak production.