Immunomodulatory effects of egg white peptides on immunosuppressed mice and sequence identification of immunomodulatory peptides

In this study, egg white peptides (EWP) were prepared using preheat treatment combined with a bienzymatic hydrolysis. Results on peptide yield and molecular weight distribution showed that preheat treatment could obviously promote egg white hydrolysis. The yield of EWP obtained from neutral-alkaline protease treatment was 74.62% ± 0.23% and 92.69% of EWP was between 200 Da and 500 Da. Supplementation with 750 mg/kg/d EWP significantly alleviated the decrease of immune organ index in immunosuppressed male BLAB/c mice caused by cyclophosphamide. The pathological changes of spleen showed that EWP could also alleviate the damage of spleen tissue. The number of white blood cells in peripheral blood and the levels of serum cytokines (IL-6, IL-2 and TNF-α) in 750 mg/kg/d EWP group were significantly higher than the model group. The immunomodulatory effects of EWP might be related to the presence of abundant branched-chain amino acids, which were important components of immunomodulatory peptides. Eight possible immunomodulatory peptides were identified from EWP by High Performance Liquid Chromatography-Mass Spectrometry in combination with ProteinLynx Global SERVER and mass spectral database. Therefore, EWP may have potential as a natural immunomodulator for the prevention of immune damage caused by external influences.