Parenteral supplementation with a fish-oil emulsion prolongs survival and improves rat lymphocyte function during sepsis

Nutritional intervention with omega-3 fatty acids during trauma and infection has been shown to improve the clinical outcome of patients and the survival rate in laboratory animals. This study evaluated the effects of parenteral administration of lipid emulsions containing fish oil (FO) or soybean oil (SBO) on survival and T-lymphocyte response during sepsis. Male Sprague-Dawley rats (250-275 g) were prepared for parenteral feeding 4 d before inducing sepsis by cecal ligation and puncture (CLP). Standard resuscitation was provided with normal saline. Thirty minutes after completing CLP, sham control or CLP rats were infused continuously with saline or a parenteral diet containing SBO or a 1:1 FO:SBO emulsion. The survival rate was significantly improved in rats receiving the FO-supplemented diet, with 50% alive by 120 h in comparison with the saline-infused, chow-fed rats (0% alive by 120 h) or the SBO-fed rats (12% alive at 120 h). The T-lymphocyte response was evaluated at 24 h after CLP. Sepsis led to a decline in lymphocyte proliferation in rats infused with saline or the SBO emulsion, which was associated with a greater release of splenocyte interleukin-10, transforming growth factor-beta and prostaglandin E2. Administering the 1:1 FO:SBO parenteral diet during sepsis improved the survival rate and prevented the sepsis-induced suppression of lymphocyte proliferation and interleukin-2 release. The FO effect on lymphocyte function was associated with decreased splenocyte release of transforming growth factor-beta and prostaglandin E2.