Effects of dietary microalgae, 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 fatty acid 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 concentration were 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 diet containing microalgae plus Se and I. Yolks from all supplemented diet groups exhibited a significant reduction in n-6 fatty acid content compared with the control group. The docosahexaenoic acid (DHA) content of yolks was higher (P < 0.01) in all supplemented 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 of yolks can be achieved by feeding hens a microalgae-rich diet, which avoids the unpleasant flavours associated with fish oil supplementation. Dietary inorganic Se, especially in combination with I, can enhance the concentration of Se in eggs.