Assessment of the effect of selected substances used for disinfection of hatching eggs on hatching results in chickens

Abstract

The aim of the study was to investigate whether egg disinfectants have a toxic effect on the tissues of the developing chicken embryo. The basic active ingredients of the disinfectants tested were quaternary ammonium compounds (Amino-Steril); stabilized peracetic acid and hydrogen peroxide (Oxydion); glutaraldehyde, didecyldimethylammonium chloride, quaternary ammonium compounds and benzyl-C12-C16-alkyldimethyl (Viron FF); and stabilized hydrogen peroxide (Hydro-Clean). The tests were performed on hatching eggs from Ross 308 parent stock. The potential adverse effects of aqueous solutions of the disinfectants were tested in vitro using the Hen’s Egg Test – Chorioallantoic Membrane (HET-CAM). The results were confirmed in in vivo tests by analysing the hatchability of disinfected eggs. In the in vitro tests, aqueous solutions of the disinfectants with concentrations of 1%, 0.5%, 0.25% and 0.125% were spotted onto previously prepared chorioallantoic membranes of live eight-day-old chicken embryos (n = 8 embryos/disinfectant/concentration). The toxicity of the substances was assessed on the basis of the occurrence of hyperaemia, haemorrhage, and coagulation of the blood vessels of the membrane after 0.5, 2 and 5 minutes, using the 21-point Luepke scale. The in vivo testing consisted of two experiments conducted under production conditions, using eggs from flocks in the peak (37th week of life) and the final (54th week) laying periods. The eggs were sprayed with a 1% aqueous solution of disinfectant (400 eggs/disinfectant/experiment) about 2 hours before incubation. Hatching results, the stage of embryonic development at the time of death and any cases of infection were evaluated. The HET-CAM tests showed that the 1% solutions of the disinfectants induced strong (Hydro-Clean), moderate (Oxydion and Amino-Steril) and weak (Viron FF) reactions, while the 0.125% concentration produced a weak reaction or none. Analysis of hatching results showed that they were not affected by the disinfectants. However, in the case of laying hens in their final production period, spraying with aqueous solutions of each agent reduced losses due to early embryo mortality. In conclusion, the disinfectants tested can be safely used in poultry hatcheries