Dietary Effects of Fish Oil Containing EPA and DHA on Performance, Fatty Acid Deposition, Plasma Oxylipins, and Cytokines in Response to LPS Challenge in Laying Hens.

BACKGROUND

Including fish oil (FO) in laying hen diets is an attractive strategy to increase egg and tissue omega (ω)-3 PUFA, while simultaneously protecting hens from potential immune challenges.

OBJECTIVES

This study compared effects of a standard hen diet with FO containing EPA and DHA on plasma oxylipins and splenic cytokine expression in LPS-challenged layers.

METHODS

Twenty-four 40-wk-old Dekalb White layers were randomly assigned to either control (no EPA or DHA) or FO (0.4 g/100 g EPA and DHA) diets. After 6 wk, hens were challenged with LPS (8 mg/kg body weight; i.v.) or saline 2 h before termination. PUFA were analyzed by GC, free oxylipins by HPLC/MS/MS, and splenic cytokines by quantitative reverse transcriptase-polymerase chain reaction. Data were analyzed by principal component analysis and analysis of variance.

RESULTS

Yolk, liver, and plasma were enriched in ω-3 PUFA and reduced in ω-6 PUFA in FO group. Interestingly, LPS increased liver α-linolenic acid (ALA) and plasma ALA and DHA in FO-fed hens (P < 0.05). FO-fed hens exhibited higher plasma EPA and DHA oxylipins, and lower ω-6 oxylipins. Because of an interaction with FO, LPS increased ∼14% of oxylipins in control hens, particularly octadecanoids from ALA and linoleic acid, whereas in FO-fed hens, LPS decreased ∼31% of oxylipins derived from ω-6 and also from ω-3 PUFA (P < 0.05). Consistent with these putatively anti-inflammatory effects, FO decreased oxylipins associated with higher soluble epoxide hydrolase activity in saline-treated hens. However, FO increased these oxylipins in LPS-treated hens (P < 0.05). LPS induced the expression of splenic cytokines, and this was not altered by diet.

CONCLUSIONS

Dietary EPA and DHA enrich ω-3 PUFA in yolk, liver, and plasma of layers, and modulate plasma oxylipins. Whether oxylipin changes mediate or are a consequence of FO effects on LPS-induced inflammation remains to be elucidated.