Effects of a fish oil diet on pigs' cardiopulmonary response to bacteremia

Since an ω3 fatty acid (FA) diet may have beneficial effects in inflammatory processes, we tested the hypothesis that the physiologic response to sepsis could be modified by altering the eicosanoid precursor pool via an ω3 FA diet. Two groups (n = 8) of pigs were prefed for 8 days either an ω3 FA or an ω6 FA diet (Weaner Pig Feed with either menhaden or corn oil to produce a eucaloric feed with 15% fat) and then injected with live Escherichia coli. The ω3 FA diet increased the concentration of eicosapentainoic acid (EPA, 20:5ω3) in plasma lipids, and increased the ratio of EPA to arachidonic acid (AA, 20:4ω6) in platelets from 1:20 to 1:1 over the 8 days. Following the injection of bacteria, there was a fall in PaO₂ and blood pressure that was attenuated (p < 0.05) by the ω3 FA diet. The ω3 FA diet, compared to the ω6 FA diet, also attenuated the rise in thromboxane B₂ (3.0 ± 1.1 vs 12.9 ± 5.7 ng/mL) and 6 keto-PGF(1α) (0.8 ± 0.5 vs 1.7 ± 1.1 ng/mL) associated with bacteremia. We conclude that dietary ω3 FA attenuated the physiologic response to sepsis, possibly by modifying arachidonic acid metabolism.