Effect of feeding flax and two types of antioxidants on egg production, egg quality and lipid composition of eggs

The present study was conducted to investigate the effect of feeding flaxseed and 2 types of antioxidants [α-tocopherols (Toc), butylated hydroxy toluene (BHT)] at 3 levels (50, 100, and 150 IU or mg/kg) on production performance, egg quality, fatty acid profile, Toc, and egg cholesterol content. Twenty-four 1-wk-old ISA Brown Leghorn laying hens (n = 96) were kept in cages and were fed a corn- and soybean meal-based diet for 56 d: control (no flax, no antioxidant), 10% flax with no antioxidant, or 10% flax + antioxidants. The flax-based diets had no effect on egg production, egg weight, egg mass, or feed conversion (P > 0.05) when compared with the control diet. Feed intake was reduced in hens fed the flax diets (P < 0.05, except flax + 150 mg of BHT) as compared with those fed the control diet. Egg weight, yolk weight, shell weight, albumen weight and height, Haugh units, yolk color, and shell thickness were unaffected by feeding flaxseed (P > 0.05). Lower levels of saturated fat were observed in eggs of hens fed the flax + Toc and flax + 50 mg of BHT diets when compared with hens fed the other diets (P < 0.05). Eggs from hens fed flax had increased α-linolenic (18:3n-3), eicosapentaenoic (20:5n-3), and docosahexaenoic (22:6n-3) acid levels and a decreased arachidonic acid (20:4n-6) level and total n-6:n-3 ratio when compared with control eggs (P < 0.05). Total n-6 fatty acids were lowest in eggs from hens fed flax + 50 IU of Toc, flax + 50 mg of BHT, flax + 100 mg of BHT, and flax + 150 mg of BHT. Total n-3 fatty acids were highest in eggs from hens fed flax + 50 mg of BHT. Flaxseed and antioxidant supplementation had no effect on egg cholesterol content (P > 0.05). Inclusion of Toc led to more than 4.5- to 12-fold increases in Toc in eggs from hens fed flax-based diets. These data demonstrate that eggs with increased n-3 fatty acids and Toc can be produced by minor diet modifications without affecting egg quality parameters.