Influence of in ovo injection and subsequent provision of silver nanoparticles on growth performance, microbial profile, and immune status of broiler chickens

Lane Pineda,¹ Ewa Sawosz,² Charlotte Lauridsen,³ Ricarda M Engberg,³ Jan Elnif,1 Anna Hotowy,¹ Filip Sawosz,¹ Andrè Chwalibog<sup>1

1</sup>Department of Veterinary Clinical and Animal Sciences, Copenhagen University, Denmark; ²Department of Animal Nutrition and Feed Science, Warsaw University of Life Sciences, Poland; ³Department of Animal Science, Aarhus University, Denmark

Background: Because of their unique biological properties and strong antimicrobial activity, silver nanoparticles have received considerable attention and been used widely in an increasing number of consumer and medical products. In the present study, the potential of silver nanoparticles as an alternative antimicrobial growth-promoting supplement for broiler chickens was investigated.
Methods: On day 1 of incubation, two groups of fertile eggs were injected with colloidal silver nanoparticles 10 mg/kg or 20 mg/kg. A third group was not injected and designated as a control group. At day 7 post-hatching, drinking water containing three silver nanoparticle concentrations (0, 10, and 20 mg/kg) was offered for 4 weeks. Body weight and feed consumption were measured weekly. At days 22 and 36, blood samples and intestinal contents were collected to evaluate the effects of the silver nanoparticles on plasma concentrations of immunoglobulins (IgG and IgM) and intestinal microflora.
Results: In ovo injection of silver nanoparticles 10 mg/kg and 20 mg/kg and subsequent provision in the drinking water during the post-hatch period reduced feed intake by about 5.0 g/day (P = 0.02) and body weight by about 41.0 g (P = 0.001); however, no concurrent effect on feed conversion ratio was observed. Bacterial populations in the ileum were not affected. Numbers of lactose-negative enterobacteria and lactic acid bacteria decreased in the cecum (P < 0.05). Silver nanoparticle supplementation increased the concentration of acetic acid (P = 0.006), but not the concentrations of butyric, propionic, valeric, and succinic acid in the cecum. No treatment effects on plasma concentrations of IgG and IgM were noted.
Conclusion: Silver nanoparticles affect feed intake, acetic acid concentration, numbers of lactose-negative and lactic acid bacteria, and immunoglobulin levels in broiler chickens. Silver nanoparticles are a potent antimicrobial agent for use in these birds. However, their activity and impact on growth performance should be explored further in a commercial poultry production setting.

Keywords: silver nanoparticles, feed additives, chicken, intestinal microflora, immunoglobulins