The effect of dietary lipid on gut microbiota in a senescence-accelerated prone mouse model (SAMP8)

Gut microbiota change with aging and diet. In a previous study, it was shown that a moderate-fat diet enriched with fish oil had beneficial effects for elderly patients, so we examined the effect of this diet on aging-related changes in gut microbiota in this study. We used 3-month-old male senescence-accelerated prone mice (SAMP8). The mice were fed a normal diet containing 4 g soybean oil/100 g of diet for 6 months and then divided into 4 groups: (1) the Baseline group, ended breeding at 6 months old; (2) the Control group, continued on a normal diet until 15 months old; (3) the MF group, switched to a moderate-fat diet until 15 months old; and (4) the MF + FO group, switched to a moderate-fat diet enriched with fish oil until 15 months old. When mice were 6 or 15 months old, fecal samples were collected and gut microbiota analysis was performed. Gut microbiota analysis at the genus level showed that bacteria known to increase in association with fatty liver and intestinal inflammation increased with aging. However, this alteration was largely inhibited by the moderate-fat diet enriched with fish oil. On the other hand, there was a decrease with aging in the bacteria that play a role in energy consumption, but this alteration was inhibited by the moderate-fat diet enriched with fish oil. These results suggest that a moderate-fat diet enriched with fish oil has beneficial effects on gut microbiota in aging.