Abstract
This study aimed to evaluate the effectiveness of the embryonic injection of silver nanoparticles (SilNPs) on some productive traits and hepatic gene expression of lipopolysaccharide (LPS)-challenged broilers after a 42 d rearing period. 560 fertile eggs were randomly allocated to four groups and received either of the following treatments at d 7 of incubation, control (no injection), placebo (1 mL saline), SilNP20 (20 mg/kg silver nanoparticles), or SilNP40 (40 mg/kg silver nanoparticles). After the incubation, 320 hatchlings experienced a 42 d standard rearing period. Live body weight (LBW), feed intake (FI), and feed conversion ratio (FCR) were weekly recorded. At the end of the experiment, two birds from each replicate (n = 8 per treatment) were exposed to LPS intraperitoneal injection at 48, 24, and 12 h before slaughter time. They were also used for blood, intestinal, and microbial evaluations. The hepatic mRNA levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), transforming growth factor beta (TGF-β), and insulin-like growth factor I (IGF-I) were assessed at d 1 and 42 of the experiment. Adminstration of SiLNPs improved LBW, FI, and FCR and also enhanced liver and spleen weights (P < 0.05). SilNP20 birds had significantly lower bursa of Fabricius weight (P < 0.05). SilNP20 had lower total cholesterol levels than others. There was a significant difference (P < 0.05) between SliNP40 and SilNP20 in the ratio of villus height to crypt width. Compared to control groups, chicks of SilNP20, but not SilNP40, showed a significant increase in the relative expression of TNF-α, IL-6, TGF-β, and IFG-I genes at d 1. On d 42, however, both SilNP20 and SilNP40 had significantly higher TNF-α and TGF-β levels than both controls. Silver nanoparticles did not significantly affect the microflora of the ileum and cecum in the current study. In summary, SilNPs administration to chick embryos showed a long-term positive effect on their productive performance.