Modulation of gut microbiota in rats fed whole egg diets by processing duck egg to preserved egg.

Pidan, as the preserved duck egg, is a traditional alkaline-pickled food in China. Previous studies have suggested preserved egg white has an anti-inflammatory effect, though the mechanism of action was unclear. In this work, the difference of peptides distribution in the digestive products was identified from those of duck egg. The effects of preserved egg diet on the modulation of gut microbiota as well as the alteration in fecal metabolites were further investigated. Minor variations of gut microbiota in phylum level were observed between preserved and fresh duck egg diet groups, even though, preserved egg diet intake attributed to increases in the relative abundance of Prevotella and Phascolarctobacterium (p < 0.05), while Ruminococcaceae and Allobaculum were quantitatively decreased (p < 0.05). In terms of metabolites, the contents of acetic acid (p < 0.01) and propionic acid (p < 0.05) were significantly increased in the preserved egg diet group. It was speculated that the preserved egg diet might alter the proportion of short-chain fatty acids (SCFAs) in the gut of rats by modulating specific intestinal bacteria, and subsequently play an active role in anti-inflammatory effects. Compared to the fresh egg group, the bacterial produced SCFAs of preserved egg group were increased in abundance (p < 0.05), which may have potential anti-obesity and anti-inflammatory effects. The results provide a novel insight into the relationship between preserved egg intake, gut microbiota and potential positive effects on host health.