Dietary n-3 fatty acids decrease the leukotriene B 4 response ex vivo and the bovine serum albumin-induced footpad swelling index in New Hampshire hens

The effects of feeding New Hampshire hens different amounts of n-6 and n-3 fatty acids on plasma and immune tissue fatty acid profiles, leukotriene (LT) B 4 response ex vivo in stimulated thrombocytes, serum non-esterified fatty acid (NEFA) concentrations, and bovine serum albumen (BSA)-induced footpad swelling index were investigated. Seventy-two New Hampshire hens (n = 24/treatment) were fed diets supplemented with 3.0% sunflower oil (Diet I), 1.5% sunflower oil + 1.5% fish oil (Diet II), or 3.0% fish oil (Diet III). After 46 d on experimental diets, concentrations of C20:5n-3 and C22:6n-3 were higher in plasma, thrombocytes, and spleens of hens fed Diet II and III compared with hens fed Diet I (P ≤ 0.05). Thrombocytes from hens fed Diet III that were stimulated ex vivo with calcium ionophore A23187 produced less LTB 4 than those from hens fed Diets I and II (P < 0.05). The serum NEFA concentrations were 0.31 ± 0.12, 0.25 ± 0.08, and 0.17 ± 0.06 mEq L -1 for hens fed Diets I, II, and III, respectively (P = 0.07). The cell-mediated immune response, based on results of a BSA-induced footpad swelling index at 48 h, was less in hens fed Diet III (P < 0.05) compared with hens fed Diets I or II. These results indicate that increasing the concentration of n-3 fatty acids in diets fed to New Hampshire hens might depress cell-mediated immunity and the pro-inflammatory LTB 4 response. Key words: N-3 fatty acids; Leukotriene B 4 ; Thrombocytes