Introduction Reproductive hormones, lipid and mineral metabolisms, aging and stress are the main factors that influence the performance, egg production and egg quality of laying hens. Hormones are involved in the formation of egg, which is a

Research background. The cytotoxicity on various vital cell lines and the activity on foodborne pathogens (murine norovirus 1 as a norovirus surrogate and Campylobacter jejuni) of methanolic Urtica dioica L. leaf extract (UDE) were studied. Experimental approach. The cytotoxic concentration of 50% (CC50) was measured by the linearity between UDE concentrations and cell viability. Antibacterial effects on C. jejuni were analyzed by the broth microdilution method with a spectrophotometer. The virucidal and antiviral activities of UDE were determined by the virus titration method on the host cell infectivity and expressed as the tissue cell infective dose of 50% using the method of Spearman–Karber. Results and conclusions. The CC50 of UDE was determined on macrophage as the virus host cell. MIC and MBC of UDE were determined as 5 mg/ml and 20 mg/ml for both C. jejuni isolated from poultry meat and the standard strain. UDE inhibited MNV-1 on three pathways of host cell infectivity at approximately the same 50% inhibitory concentration (1.45-1.87 mg/ml). In conclusion, the present study tried to explain in detail the dose-dependent activity of Urtica dioica L. leaf extract on two important foodborne pathogens causing outbreaks worldwide. The results showed that it might be a safe and alternative food additive and supplement candidate at safe concentrations.