Production Performance and Properties of Eggs from Hens Fed Diets Differing in Corn Grain Hardness, Vitamin A Supplementation Level, and Mineral Form

This study evaluated how corn grain hardness, vitamin A supplementation level, and trace mineral form influence production performance and egg properties in laying hens. In a 2 × 3 × 2 factorial design, 252 Lohmann Brown hens received diets containing soft- or hard-type corn hybrids; 5000, 10,000, or 20,000 IU/kg of vitamin A; and inorganic or organic trace minerals for 63 days. Hard-type corn increased daily egg mass, improved feed conversion ratio, and produced eggs with higher MUFAs and SFAs but lower PUFAs and n-3, resulting in a less favorable n6/n3 ratio, while also increasing susceptibility to Fe-induced lipid oxidation despite lower PUFAs. Increasing dietary vitamin A to 10,000-20,000 IU/kg increased egg weight and shell strength, linearly increased yolk retinol, and decreased tocols, with 20,000 IU/kg markedly increasing Fe-induced MDA formation without major changes in PUFAs. Trace mineral form had minor effects on performance and fatty acid profile. Overall, modest changes in laying hen diet, such as corn hybrid, vitamin A supplementation level, and trace mineral form, significantly modulated egg nutritional composition and oxidative stability. A high dietary vitamin A level may compromise the oxidative resilience of enriched eggs, while interactions of trace mineral form with corn hybrid and vitamin A suggest its potential modulatory role in lipid oxidation pathways.