Egg white peptides suppress ghrelin secretion from the stomach by activating the mTOR signaling pathway in rats.

Egg consumption has usually been associated with reduced food intake. This study aimed to investigate the effects of egg white-derived peptides on the plasma ghrelin levels and its secretion from the stomach in rats after oral administration. The findings revealed that egg white protein hydrolysate (EWH) generated through simulated gastrointestinal digestion significantly decreased food intake, plasma ghrelin levels, and ghrelin expression in the stomach and duodenum of normal and high-fat diet (HFD)-fed rats. EWH effectively ameliorated the glucose and lipid metabolism disorders and liver injury in HFD-fed rats. In addition, EWH directly inhibited ghrelin secretion in isolated gastric fundus tissue and gastric fundal mucosal primary cells. RNA-sequencing analysis of the gastric fundal mucosal primary cells revealed that EWH treatment induced upregulation of 1590 genes and downregulation of 2650 genes in gastric fundal mucosal primary cells with significant enrichment of the mTOR signaling pathway in KEGG analysis. Moreover, the result of the western blot showed that EWH significantly improved the phosphorylation of mTOR in the gastric fundus, suggesting that EWH might suppress ghrelin secretion by activating the mTOR signaling pathway. This study shows the suppressive effect of EWH on ghrelin secretion and its potential as a bioactive ingredient in functional foods for managing food intake and body weight.