Effects of a moderate-fat diet that is enriched with fish oil on intestinal lipid absorption in a senescence-accelerated prone mouse model

Objectives: We examined a moderate-fat (MF) diet that is enriched with fish oil (FO) and assessed whether lipid absorption was inhibited in senescence-accelerated prone mice (SAM-P8). Methods: All mice (N = 70) were fed a normal diet that contained 4 g soybean oil/100 g of diet for 6 mo and then divided the mice into four groups (n = 10 or 20/group). Mice in the baseline group were euthanized at 6 mo old, those in the control group continued on a normal diet until 15 mo of age, those in the MF diet group switched to an MF diet (8 g soybean oil/100 g of diet) until 15 mo of age, and those in the MF + FO group switched to an MF diet that was enriched with FO (6.4 g soybean oil + 1.6 g FO/100 g of diet) until 15 mo of age. Results: The area under the curve for lipid absorption decreased with age but lipid absorption tended to be less attenuated with an MF diet that contained FO. Messenger RNA (mRNA) levels of apolipoprotein B, fatty acid transport protein 4, and microsomal triacylglycerol transfer protein in the small intestine decreased with age but tended to be maintained with an MF diet with or without FO. A histologic analysis of the small intestine showed that villi degenerated with age but the decline was less in mice in the MF + FO group. Conclusions: The results of this study suggest that MF + FO diets can inhibit the attenuation of lipid absorption commensurate with aging in SAM-P8 via a delay of the natural degeneration that occurs in small intestinal villi over time.