Effect of dietary supplementation of unsaturated fatty acids and vitamin E upon yolk lipid composition and alpha- tocopherol incorportation into the egg yolk

Abstract

To investigate the effect of dietary sources of polyunsaturated fatty acids - canola oil (6%), flaxseed (20%) or the combination of both (3% canola oil and 10% flaxseed), and vitamin E supplementation (0,100 e 200 IU/kg of diet) upon the fatty acids and alpha-tocopherol deposition into the eggs, 288 Babcock laying hens were used for a 11 week experimental period. Hens fed 20% flaxseed diet showed a significant reduction of egg weight, feed efficiency, egg production, eggshell thickness and eggshell weight. The inclusion of flaxseed in the diet increased the polyunsaturated fatty acids, depressed monounsaturated fatty acids incorporated into the egg yolk, and increased the ratio P/S (polyunsaturated:saturated fatty acids). Yolk alpha-tocopherol concentration was proportional to its content in the diet (R²=0.9613). Birds fed diets with 6% of canola oil had greater alpha-tocopherol deposition into the eggs.