Green Synthesis of Silver Nanoparticles from Chlorella vulgaris Aqueous Extract and Their Effect on Salmonella enterica and Chicken Embryo Growth

Silver nanoparticles (AgNPs), synthesised using <i>Chlorella vulgaris</i> algal extract and silver nitrate, are studied in medicine for their antibacterial properties in poultry. This study assessed the effect of AgNPs on bacterial inhibition and early development and blood parameters in Ross 308 chicken embryos. AgNPs were characterised using transmission electron microscopy, scanning electron microscopy with a focused ion beam, UV-Vis spectroscopy, and a zetasizer. The antibacterial properties of the AgNP colloid against <i>S. enterica</i> were assessed using minimal inhibitory concentration, minimal bacterial concentration, and PrestoBlue assays. AgNP colloid (2 mg/L) was injected into egg albumen on day 0. Chicken embryos were incubated for 3 and 16 d. The effect of AgNPs on 3 d old embryos was evaluated based on mortality and somite count using the Hamburger-Hamilton classification. For older embryos, mortality, dimensions, anatomical changes, organ mass, plasma liver enzymes and antioxidants, and red blood cell morphology were determined. Blood samples from the control group embryos were assessed for the impact of AgNPs on hemolysis. AgNPs inhibited <i>S. enterica</i> growth at concentrations >6.75 mg/L. A 3 d exposure to AgNPs caused an insignificant decrease in the number of somites without affecting embryo mortality. However, a 16 d exposure to AgNPs reduced live embryos and plasma antioxidants, changed the levels of ALT, AST, and GGT, altered red blood cell morphology, and caused hemolysis. Toxicity of AgNPs was model-dependent, whereby the chicken embryo was more sensitive to AgNPs than the bacterium.