Utilization of microalgae as a feed ingredient for laying hens: A meta-analysis

This meta-analysis aimed to evaluate the effects of supplementing varying levels and types of microalgae on the performance of laying hens. A total of 18 relevant studies, comprised of 71 data points, were analyzed using a mixed model approach. Microalgae supplementation was treated as a fixed effect, while the different studies were considered as random effects. The results showed that supplementation with any type of microalgae, up to 10%, did not negatively impact the laying hen performance, including egg production, feed conversion ratio, feed intake, body weight, and fatty acid composition. Increasing levels of microalgae supplementation resulted in a significant linear improvement (P < 0.05) in the egg quality parameters, including the eggshell strength, shell thickness, shell weight, haugh unit, and yolk color. Additionally, there were significant interaction effects (P < 0.05) between the supplementation levels and the types of microalgae on the albumen weight and the egg fatty acid composition (EPA, omega-6, and omega-3 fatty acids). Brown microalgae had a greater effect on increasing the n-3 fatty acid content of eggs compared to green microalgae. In conclusion, microalgae can be a promising source of n-3 fatty acids and bioactive compounds to improve the egg quality without negatively affecting the laying performance.