Oral Administration of Hydrolyzed Egg Yolk Peptides With Low Molecular Weight Increased Bone Density by Regulating Bone Metabolism and Immune Responses.

Hydrolyzed egg yolk peptides have been proven to improve bone density in animals of different ages. However, the peptides profile and function of low molecular weight hydrolyzed egg yolk peptides have not been studied, which may have better efficacy, the relationship between these peptides and humoral immunity has not been noticed yet. This study analyzed the amino acid composition and molecular weight distribution of Shinupep, a low-molecular-weight hydrolyzed egg yolk peptides suitable for industrial production. It also investigated its effects and mechanisms in improving osteoporosis in ovariectomized rats. Oral administration 8.33 and 50 mg/d/kg Shinupep significantly increased the levels of the bone formation marker BGP while reducing the levels of bone resorption markers alkaline phosphatase and tartrate-resistant acid phosphatase. It also notably enhanced humoral immunity markers immunoglobulin G and immunoglobulin M and lowered the inflammatory marker receptor activator for nuclear factor-κB ligand. Additionally, Shinupep significantly increased cortical bone thickness, trabecular number, and bone density. The improvements in bone density and microarchitecture observed with the Shinupep were achieved through the regulation of bone metabolism, as well as modulation of both humoral and cellular immunity. Notably, this is the first time to reveal the role of humoral immunity in the hydrolyzed egg yolk peptides' ability to ameliorate osteoporosis.