Effects of parenteral fish oil on plasma nonesterified fatty acids and systemic inflammatory mediators in dogs following ovariohysterectomy

Objective To evaluate the effects of intravenous (IV) infusion of fish oil (FO) emulsion following ovariohysterectomy (OVH) on inflammatory mediators and plasma omega-3 nonesterified fatty acids (NEFA) concentrations in dogs. Design Prospective clinical study. Setting University teaching hospital. Animals Twenty-nine privately owned dogs undergoing routine OVH. Interventions Postoperative 3-hour IV infusion of saline (n = 9), FO (Omegaven, n = 10), or soybean oil (SO, intralipid, n = 10) emulsion and blood collected before, 5 and 24 hours following OVH for plasma NEFA and RBC membrane fatty acids (FAs) concentrations, leukocyte cytokine production capacity, and C-reactive protein (CRP) measurement. Measurements and Main Results Plasma omega-3 NEFA, eicosapentaenoic acid, docosahexaenoic acid, and total long-chain omega-3 FA significantly increased shortly after FO infusion (8.8 ± 3.3 μM, 13.6 ± 5.6 μM, and 25.1 ± 9.6 μM, respectively) compared to SO (0.7 ± 0.9, 2.3 ± 1.8, and 4.2 ± 3.0 μM, respectively) and saline infusion (1.6 ± 2.5, 2.6 ± 3.1, and 5.9 ± 6.4 μM, respectively). Plasma CRP concentration significantly increased after OVH, but with no significant group differences. A weak negative correlation occurred between post-OVH CRP and postinfusion total long-chain omega-3 FA concentrations (r2 = 0.21, P = 0.014). Stimulated leukocyte interleukin (IL) 6 production capacity increased (P = 0.001) after OVH in all groups; SO infusion resulted in reduced leukocyte IL-6 production capacity (1048.1 ± 277.7 pg/mL) compared to FO (1299.9 ± 302.1 pg/mL, P = 0.048) and saline infusions (1499.0 ± 363.1 pg/mL, P = 0.01). No significant group difference was observed in leukocyte IL-10 and tumor necrosis factor α production capacities. Conclusions Postoperative administration of FO emulsion increases plasma omega-3 NEFA concentrations promptly, but does not significantly attenuate CRP production or leukocyte cytokine production capacity. FO infusion at the dosage used in the present study can be safely used in dogs, but it was not clearly beneficial in decreasing post-OVH indices of inflammation.