Abstract
The effects of supplementing laying hen diets with 0, 50, or 100 g flaxseed meal (FSM)/kg over a 12-week period on liver and egg yolk fatty acids (FA) composition, liver and serum lipid peroxidation [thiobarbituric acid reactant substances (TBARS), activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx)], serum lipids (triglyerides, total cholesterol, high density lipoprotein cholesterol), proteins (total protein, globulin and albumin), and immune response [serum antibody titres to sheep red blood cells (SRBC) and white blood cell count (WBC) and differential (heterophils (H), lymphocytes (L), monocytes (M), eosinophils (E) and basophils (B)] of laying hens were studied. The FSM diets increased total polyunsaturated FA (PUFA) and omega-3 FA of a-linolenic acid (C18:3(n-3)), docosapentanoic (C22:5(n-3)) and docosahexaenoic (C22:6(n-3)), and they reduced total monounsaturated FA (MUFA) and total omega-3/total omega-6 FA (Sigma n-6:Sigma n-3) ratio in the liver and egg yolk. Hens fed the FSM diets had a higher serum anti-SRBC and a lower blood H:L ratio. The 100 g FSM/kg diet increased liver TBARS level when compared with the control diet. Dietary FSM did not influence levels of TBARS, SOD, lipids and proteins in the serum, SOD and GPx in the liver, and blood count of M, E, B and total WBC. It was concluded that the addition of FSM to the diet of laying hens enhanced immune response of birds, increased omeg-3 FA and PUFA, and reduced MUFA and Sigma n-6:Sigma n-3 ratio in the liver and egg yolk, and that of 100 g FSM/kg diet increased hepatic lipid peroxidation.