Abstract
The present study aimed to evaluate what dosage of gold nanoparticles (GNPs) would improve growth performance, antioxidant levels and immune defense in broiler chickens. The experiment was carried out on 90 one-day-old mixbred Cobb chicks. The birds were allocated into three groups with three replicates. Group (1) kept as a negative control. Groups (2) and (3) received 5, 15 ppm GNPs via drinking water weekly for 35 days of chicks' life. Blood samples were collected at 8, 15, 22 and 36 days for oxidative stress evaluations and immunological studies. The birds were slaughtered at the ages of 36 days and thymus, spleen, busa of Fabricius and liver were collected for histopathological description, RT-PCR analysis and DNA fragmentation assay. Our results confirmed that adding of 15ppm GNPs in drinking water were induced remarkable blood oxidative stress damage, histopathological alterations, up-regulation of IL-6, Nrf2 gene expression, and DNA fragmentation in the examined immune organs of the broiler chickens as well as a significant reduction in the antibody titer against Newcastle (ND) and avian influenza (AI) viruses were noticed. On the other hand, the group received 5 ppm GNPs noticed better growth performance with the enhancement of the final food conversion ratio (FCR) without any significant difference in the previous toxicological and immunological parameters compared with the control groups. We suggest that feeding of 5ppm GNPs could improve the antioxidant capacity, immunity and performance in poultry but further food quality assurance tests are required in the future to confirm its safety for people.