Effect of dietary supplementation of fish oil on intestinal barrier function in mouse fed with high-fat diet

Objective  To investigate the effect of dietary supplementation of fish oil on the barrier function of mouse fed with high-fat diet (HFD).

Method  36 C57BL/6J female mice (4-week-old) were randomly divided into control group (CK), HFD group, and HFD +fish oil group, with 12 mice in each group. Mice in three groups were fed with basal diet, HFD and HFD supplemented with 5% fish oil (iso caloric with HFD), respectively. The experiment lasted for 21 weeks, and the food intake and body weight of mice were measured weekly. During the experiment, intestinal permeability of each mouse was measured, and the fat content and energy in feces were determined. At the end of the experiment, endotoxin levels in serum were detected, and intestinal morphology, the number of intestinal goblet cells, and the expressions of intestinal tight junction proteins and inflammatory factors were examined.

Result  Compared with HFD group, addition of fish oil in diet significantly increased food intake and energy intake, decreased fecal crude fat content and energy excretion, while significantly reduced body weight of mice (P<0.05). In terms of intestinal morphology, compared with HFD group, addition of fish oil significantly increased the ratio of villus height to crypt depth (l_V/d_C) by 43.1% in mouse jejunum and 67.5% in ileum and the number of goblet cells in ileum villous by 16.7% (P<0.05). Compared with HFD group, addition of fish oil reduced the fluorescent glucan and endotoxin levels in serum by 34.3% and 50.4% respectively (P<0.05). Addition of fish oil also reversed the decrease in expressions of intestinal tight junction proteins caused by HFD. In terms of expression of inflammation factors, compared with HFD group, addition of fish oil significantly decreased the expressions of proinflammatory factors includingIL-8, IL-6 and IL-1β, and significantly elevated the expression of anti-inflammatory factor IL-10 in mouse jejunum and ileum (P<0.05).

Conclusion  Dietary supplementation of fish oil can reduce the HFD-induced impairment of intestinal barrier function, which might be associated with the fish oil reducing intestinal inflammation.