Attenuation of the febrile response in guinea pigs by fish oil enriched diets.

The influence of dietary lipid manipulation on the fever response to an injection of murine recombinant Interleukin-1 (rIL-1) in guinea pigs was examined. The animals were fed diets identical except for the lipid source for periods of 5 and 6 wk. In vitro thromboxane B2/B3 (TxB2/B3) production in collagen-stimulated whole blood was also measured. One diet was enriched with menhaden oil, high in the omega-3 series of fatty acids. The other diet contained safflower oil, consisting primarily of the omega-6 fatty acid linoleic acid (74%). Animals fed the fish oil-enriched diet for 6 wk not 5 week had a blunted fever response after rIL-1 injection. This was associated with a 27% increase (p less than 0.05) in total omega-3 fatty acids in plasma phospholipids between weeks 5 and 6 in fish oil-fed animals. Safflower oil-fed animals produced a "normal" febrile response regardless of the duration of feeding. Safflower-fed guinea pigs demonstrated a significant increase in TxB2/B3 production in whole blood after 6 wks that was associated with a 25% increase (p less than 0.05) in plasma phospholipid arachidonic acid levels between weeks 5 and 6. Despite significant reductions in phospholipid linoleic acid in animals fed fish oil, arachidonic acid levels remained unchanged. In the guinea pig model used, long-term menhaden oil feeding can significantly blunt the febrile response induced by exogenous Interleukin-1. Also, a high intake of linoleic acid as seen in safflower oil feeding can significantly increase thromboxane production in stimulated whole blood.(ABSTRACT TRUNCATED AT 250 WORDS)