Impact of omega‐3 fatty acid supplementation on murine infectious disease resistance and hepatic gene profiles.

Abstract

The objective of this study was to examine the impact of a modest increase in the intake of eicosapentaenoic acid (EPA) on host immune response in a well-characterized murine infectious disease model. The background diet used in this study mimicked current total fat and fatty acid profiles of adults in the U.S. (i.e., US-17 diets). BALB/c mice were fed this basal diet without (basal) or with (+EPA) an additional 1.5 energy(en)% EPA (a dose equivalent to 3 g/d in humans). After 4 wk, mice were challenged with L. monocytogenes (5 x 103 colony-forming units/mouse). At 3 days post-challenge, +EPA mice had significantly more bacteria in their liver (~25-fold, p < 0.05) compared to mice fed the basal diets. Supplemental EPA did not affect sera TNF-□, IL-6, IL-12p70, IFNγ or MCP-1 at 24 h post-infection. RNA expression profiling at 24 h post-challenge illustrated thousands of genes that were up- and down-regulated in the liver following infection. In un-infected mice, EPA feeding was associated with an up-regulation of 74 genes and down-regulation of 9 genes by a factor of two or more. However after infection, EPA only affected 6 genes by 2-fold or more; all were down-regulated. Importantly, all of these +EPA-mediated “differences” in hepatic mRNA expression failed to achieve statistical significance with medium stringency correction applied.