Effects of dietary protein-oxidized soybean meal and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens

Abstract

This study investigated the effects of dietary protein-oxidized soybean meal (SBM) and quercetin on gel properties, microstructure, molecular structure and proteomics of egg white in laying hens. A total of 288 Hy-Line Gray laying hens (500 days) were assigned to three groups, basal diets, protein-oxidized SBM diet, and protein-oxidized SBM diet supplemented with 300 mg/kg quercetin. The results showed that dietary protein-oxidized SBM decreased egg albumen height, gel hardness, gumminess and chewiness, and free sulfhydryl levels, although differences were not significant (P > 0.05). Quercetin supplementation reversed above mentioned indicators (P < 0.05). Dietary protein-oxidized SBM significantly increased the protein secondary structure α-helix content, reduced β-turn content, and reduced foam capacity of egg white (P < 0.05), while dietary quercetin alleviated the corresponding index (P < 0.05). Quercetin improved the egg Haugh unit, potentially due to its ability to increase the levels of microfilament proteins.