A Comparison of the Feeding Value of Different Sources of Fat for Laying Hens: 2. Lipid, Cholesterol, and Vitamin E Profiles of Egg Yolk

Three hundred and ninety Hy-Line W36 commercial laying hens, 46 wk of age, were assigned randomly to 13 dietary treatments for 140 d. Hens were housed in cages (2 hens per cage of 25 × 40 cm) in an open-sided house and were fed diets containing 3% of different fat sources (canola oil, sunflower oil, flaxseed oil, fish oil, and a mixture of 50% flaxseed oil plus 50% fish oil) and 9% ground flaxseed with 2 levels of vitamin E (12 and 100 IU/kg) in a factorial arrangement with 5 replicates of 6 hens each. A control diet, using soybean oil, was also fed. Concentrations of saturated (S), monounsaturated (M), and polyunsaturated fatty acids (PUFA), cholesterol, vitamin E, and sensory analyses of the eggs were measured. The results showed that the lipid profile in the yolk was modified by fat sources. Cholesterol content was slightly reduced by the inclusion of greater quantities of unsaturated fatty acids in the diet. Vitamin E concentration in eggs was related to corresponding dietary levels. There was no influence of the treatments on egg flavor. These findings indicate that is possible to improve the nutritional value of eggs by using flaxseed and increasing the vitamin E content of the diet.