Introduction: Oxidative stress is one of the major growth-limiting factors that occurs due to the excessive production of reactive oxygen species (ROS) and can lead to tissue damage in vital organs such as the liver and intestine. Nanosilver toxicity is closely related to its biotransformation in biological systems, which includes surface oxidation of nanoparticles, release of silver ions, and interaction with biological macromolecules. Recently, it has been proposed that silver nanoparticles could act as one of the factors inducing oxidative stress and affect the expression of oxidative genes.
Objectives: A research was conducted to investigate the effect of silver nanoparticles coated on zeolite and organic acid on the expression of superoxide dismutase, glutathione peroxidase and catalase genes in the liver and intestine of broiler chickens.
Materials and Methods: A total of 450 one-day old Cobb chicks were divided into 5 and subdivided into 6 replicates with 15 chicks per each and were kept for 42 days in the same rearing conditions in the form of a completely random design. Experimental diets were: 1) control or basal diet 2) basal diet supplemented by 1% clinoptilolite 3) basal diet supplemented by 1% clinoptilolite coated with 0.5% nanosilver 4) basal diet supplemented by 0.15% organic acid and 5) basal diet supplemented by 1% clinoptilolite coated with 0.5% nanosilver and 0.15% organic acid. Silver nanoparticles coated on clinoptilolite were investigated using XRF and FTIR techniques. On d 21 and 42 liver and intestine samples were obtained to check gene expression of superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT).
Results: In general, the data of this research showed that the lowest relative expression of SOD, GPX and CAT genes was related to organic acid treatment on the 21^st day of the breeding period in the liver tissue, and also on the 42^nd day, experimental treatments, especially nanoparticles, had a decreasing effect on the relative gene expression that were tested. Also, in intestinal tissue, the results of our experiment showed that on the 21^st day of the breeding period, experimental treatments decreased the relative expression of the studied genes, and on d 42, silver nanoparticles treatment increased the relative expression of SOD and GPX genes, and zeolite treatment and organic acid has a decreasing effect on the expression of all three studied genes (P<0.05).
Conclusion: In conclusion, the treatments containing silver nanoparticles and zeolite showed the greatest effect on the expression of SOD, GPX and CAT genes, while the organic acid treatment decreased the relative expression of the mentioned genes. On the other hand, with increasing breeding period, the genes involved in oxidative stress were more affected by experimental treatments.