Effects of flaxseed supplementation on omega-6 to omega-3 fatty acid ratio, lipid mediator profile, proinflammatory cytokines and stress indices in laying hens

Although polyunsaturated fatty acids (PUFAs) have gained attention because of their physiological effects on inflammation and stress, their derivatives, termed lipid mediators, have been rarely examined, especially in laying hens. In this study, we aimed to investigate PUFA and lipid mediator profiles of laying hens after feeding 0, 0.9, 1.8, or 3.6% (w/w) dietary flaxseed (Lintex170) for 4 weeks. We also monitored the indices of inflammation (serum proinflammatory cytokines) and stress (serum corticosterone, ratio of heterophils to lymphocytes). In this study, flaxseed reduced the omega-6 to omega-3 FA ratio and increased several omega-3 FA-derived lipid mediators. Furthermore, levels of the proinflammatory cytokine tumour necrosis factor alpha and two stress indices (corticosterone, heterophil to lymphocyte ratio) were decreased when fed the 3.6% flaxseed diet. Overall, laying performance indices were also significantly improved by flaxseed treatment. These findings suggest that flaxseed may alleviate the stress state of laying hens by enriching omega-3-derived lipid mediators, which could improve laying performance.