Intake of Fish Oil Specifically Modulates Colonic Muc2 Expression in Middle‐Aged Rats by Suppressing the Glycosylation Process

SCOPE: Dietary fats have been shown to affect gut microbiota composition and aging gene expression of middle‐aged rats at a normal dose, but little is known about such an effect on gut barrier. In this study, the changes in colonic Muc2 expression are investigated and the underlying mechanism is also proposed. METHODS AND RESULTS: 36 middle‐aged Sprague–Dawley rats are assigned to one of the diets containing soybean oil, lard, or fish oil (4%). The rats are fed for 5 weeks and then goblet cells, Muc2 expression, and inflammatory cytokines in the colon are measured. Proteome analysis is performed. Compared with the lard and soybean oil diet groups, intake of fish oil decreases the number of goblet cells, and inhibits Muc2 and TLRs expression in the colon of middle‐aged rats, which would impair mucus barrier. Several key enzymes involved in glycosylation process, including Agr2, Gale, Gne, Pmm2, Pdxdc1, Plch1, Pfkp, Cmpk1, and Rexo2, show the lowest abundance in the fish oil diet group. CONCLUSION: Intake of fish oil at a normal dose downregulates colonic Muc2 expression. This negative effect of fish oil may involve the suppression of mucin glycosylation process.