In ovo silver nanoparticle supplementation for improving the post-hatch immunity status of broiler chickens.

Silver nanoparticles (AgNano) are known for their unique physical, chemical and biological properties, enabling cell penetration and anti-inflammatory response. In Experiment 1, the effect of an in ovo administration of AgNano (15 µg/egg; n = 360) at different incubation times (d 7 and d 18) on hatchability parameters was explored. In Experiment 2, post-hatch performance of broilers (42 d, n = 250) was studied after in ovo AgNano administration: Group T1 remained un-injected, Group T2 was the sham control and Groups T3, T4 and T5 were injected with 12.5, 25 and 50 µg AgNano, respectively, at 18 d of incubation. Chick weight, chick to egg weight ratio and hatchability as well average daily gain, average daily feed intake and feed conversion ratio were similar in all treatment groups. No variation was seen in the weight of thymus; however, the bursa and spleen weight was increased (p < 0.05) in Groups T4 and T5 in comparison to Group T1. The in vivo immune response to phytohaemagglutinin-P was increased in Group T3 in comparison to Groups T1 and T2 (p < 0.05), while the response to sheep red blood cells was increased in all AgNano-treated groups in comparison with Group T1 (p < 0.01). The expression of toll-like receptors 2 and 4 genes was up-regulated in AgNano groups in comparison with Groups T1 and T2 (p < 0.01). In summary, an in ovo supplementation of AgNano carried out at d 18 of incubation is effective and modulates the post-hatch immune response without affecting the hatchability, growth and other performance parameters in broilers.