Proteome analysis of egg yolk after exposure to zinc oxide nanoparticles

Zinc oxide nanoparticles (ZnO NPs) are promising candidates as animal diet additive. However, several studies have reported that ZnO NPs cause adverse effects on organisms. Hen egg yolk proteins play vital roles during embryonic development. Although we found ZnO NPs altered the function of the ovary and liver, the effects of ZnO NPs on egg yolk proteins are not as yet understood. In this report, egg yolk proteome was investigated after ZnO NPs treatment. A total of 37 proteins were specifically regulated just by ZnO-NP-50 mg/kg, and 22 proteins were changed solely by ZnSO₄-50 mg/kg. Seventeen proteins were regulated by both ZnO-NP-50 mg/kg and ZnSO₄-50 mg/kg treatments. Furthermore, the proteins changed by ZnO NPs or ZnSO₄ were enriched into different functional groups, respectively, by GO analysis and KEGG pathway enrichment. For the first time, this investigation reports that intact NPs produce a different impact on the egg yolk proteome compared to that of Zn²⁺. The changes in protein levels by ZnO NPs in egg yolk might influence the value of egg yolk as nutrient and the embryonic development.