The aim of the study was to recognise the effect of fodder modification with mineral-humine preparations, components rich in n-3 PUFA, and antioxidants (hibiscus, vit. A+E) on the activity of lysozyme, cysteine proteases inhibitor - cystatin and inhibitors of serine proteases in egg white. The experiment was carried out on 6 groups of Tetra SL laying hens: I control with standard feeding, II with the addition of 2% Humocarbovite, III with 3% KRM (fish-mineral concentrate with humocarbovite), IV with 3% KRM and hibiscus, V with 3% KRM and vit. A+E, VI with 3% rapeseed meal. Eggs, fresh and stored for 2 and 4 weeks at 15°C were investigated. Feeding affected the ability of cystatin to inhibit papain activity. For the fresh eggs the highest inhibition activity of cystatin was found for group VI, whilst the lowest for the group fed with 3% KRM and vit. A+E. After 4 weeks of storage only the residual activity of cystatin in eggs was determined. Feeding modification had a strong effect on the inhibition of the activity of ovomucoid and ovoinhibitor. The highest antitrypsin activity was noticed in eggs laid by hens fed with standard fodder or humocarbovite addition. However, feeding with 3% KRM and vit. A+E or rapeseed meal decreased the activity of ovomucoid and ovoinhibitor. After 4 weeks of storage, a high activity of inhibitors was achieved only in eggs with a high initial activity of inhibitors. Hens’ fodder supplementation with the studied additives lowered the activity of lysozyme, but not more than by 10% as compared to the control group. The activity of lysozyme was at the same level in all experimental groups fed with modified fodder. The enzymatic activity of lysozyme decreased slightly during storage of eggs. It can be concluded that fodder enrichment in n-3 PUFA changed the biological activity of egg white components. Only slight effect was observed upon the addition of humcarbovite and fish mineral concentrate, while the addition of KRM with vitamins A+E significantly decreased the activity of lysozyme and inhibitors in egg white. Feeding with rapeseed meal had a positive effect on cystatin activity but lowered the activity of other components, especially during storage.