Effects of dietary lutein and PUFA on PPAR and RXR isomer expression in chickens during an inflammatory response.

This study investigated the effects of dietary lutein and polyunsaturated fatty acids (PUFA) on the total lutein and lipid levels, the peroxisome proliferators activated receptors (PPAR) alpha and gamma, retinoic acid X receptor (RXR) alpha and gamma and IL-1 mRNA levels in chicken (Gallus gallus) liver and spleen. In experiment I, chickens were fed either 0, 25 or 50mg lutein in a diet with 3% PUFA fat. In experiment II, chickens were fed either 3 or 6% PUFA fat with 25mg lutein. At 23d of age, chickens were injected with LPS. LPS injection decreased the lutein content and increased the fat content in the liver and spleen in both experiments. Increasing dietary PUFA fat to 6% ameliorated the LPS-induced lutein depletion in experiment II. LPS injection increased IL-1 and decreased splenic PPARalpha, PPARgamma, RXRalpha mRNA in experiment I and II. The LPS-induced PPARalpha and RXRalpha downregulation were partially reversed by increasing the dietary lutein content to 50mg/kg feed in experiment I and by increasing the dietary PUFA fat content to 6% in experiment II. Increasing dietary lutein content to 50mg/kg feed increased PPARgamma mRNA amount only in the LPS untreated groups in experiment I. Increasing dietary PUFA fat or LPS injection in the 6% PUFA fat group upregulated PPARgamma mRNA in experiment II. Increasing dietary PUFA fat to 6% blunted the increase in IL-1 mRNA due to LPS. It is concluded that dietary lutein and PUFA fat were anti-inflammatory due to modification of immune tissue lutein content, PPAR, RXR isomers and IL-1beta mRNA levels in liver and spleen.