Egg white protein alleviated high-fat-diet-induced obesity in mice by modulating lipid metabolism and gut microbiota: novel insights into synergistic effect

Abstract Egg white protein (EWP) is considered an optimal dietary protein for weight management due to its superior amino acid profile, high biological value, and diverse metabolic regulatory functions. The study explored the effects of EWP on lipid metabolism in high-fat diet (HFD)-induced obese mice through transcriptomic and gut microbiota analyses. These results showed that EWP intake significantly influenced body weight, adipose tissue, and glucose tolerance in obese mice. EWP-1200 reduced blood lipid characteristics, decreased adipocyte size and improved hepatic injury. Moreover, EWP supplement elevated total fecal lipid, triglyceride, and total cholesterol levels in HFD-induced obese mice, concurrently suppressing fecal lipase activity. These findings suggested that EWP might enhance lipid excretion and inhibit lipid absorption. Liver transcriptomics and RT-qPCR analyses revealed that EWP significantly enhanced mRNA expression within the hepatic peroxisome proliferator-activated receptor (PPAR) signaling pathway. Notably, EWP exerted significant regulatory effects on genes such as CD-36, HSL, PPARα, FASN, and ACC, indicating that EWP might mitigate obesity by modulating lipid metabolism pathways mediated through PPAR signaling. Additionally, gut microbiota studies indicated that EWP decreased the Firmicutes/Bacteroidetes ratio, enhanced the abundance of Akkermansia, Lactobacillus, and Bifidobacterium, and significantly improved gut microbiota diversity and richness, thereby substantiating EWP's weight-loss effects on HFD-obese mice. The study clarified the efficacy and potential of egg white protein as a dietary intervention for obesity in mice, offering a scientific basis for its high value.