Fatty acid and carotenoid composition of egg yolk as an effect of microalgae addition to feed formula for laying hens

Hens were fed five diets based on rapeseed/corn oils with or without addition of the marine microalgae, Nannochloropsis oculata. Colours of egg yolk, fatty acid profiles in phospholipid (PL) and triacylglycerol (TAG) fractions and carotenoid contents were analysed. The major effects on yolk fatty acid composition were observed in the PL fraction with changes in 18:2n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3. The highest amounts of eicosapentaenoic acid and docosahexaenoic acid were obtained from the diet containing 20% N. oculata, whereas the highest arachidonic acid content in yolk was from the corn oil diet. In addition, colour (a* value) and carotenoid content increased when N. oculata was included in the diet. Long chained fatty acids were almost exclusively present in the PL fraction of yolk. This study shows that fatty acid composition and carotenoid content of egg yolk are improved by addition of N. oculata in laying hen diet. (c) 2005 Elsevier Ltd. All rights reserved.