Effects of dietary micro-algae, other lipid sources, inorganic selenium and iodine on yolk n-3 fatty acid composition, selenium content and quality of eggs in laying hens.

BACKGROUND: This aim of this study was to investigate the effects of supplementing laying hen diets with different n-3 fattyacid sources (linseed oil, fish oil and microalgae) on egg quality and fatty acid profile. The addition of inorganic selenium (Se)and iodine (I) and their effects on egg characteristics and Se concentrationwere also evaluated.RESULTS: A significantly lower egg weight was found in the control group and in groups fed a diet containing fish oil or a dietcontaining microalgae plus Se and I. Yolks from all supplemented diet groups exhibited a significant reduction in n-6 fattyacid content compared with the control group. The docosahexaenoic acid (DHA) content of yolks was higher (P < 0.01) in allsupplemented diet groups. Selenium supplementation increased the Se concentration (P < 0.001) in eggs.CONCLUSION: The results of this study provide evidence that an improvement in egg weight and in the DHA content ofyolks can be achieved by feeding hens a microalgae-rich diet, which avoids the unpleasant flavours associated with fish oilsupplementation. Dietary inorganic Se, especially in combination with I, can enhance the concentration of Se in eggs.