Effects of microalgae supplementation on performance, egg quality, yolk fatty acid levels, and blood parameters in laying hens: a meta-analysis

Abstract

Abstract Microalgae have gained attention in laying hen nutrition due to their richness in n-3 polyunsaturated fatty acids (PUFA), pigments, and antioxidants. However, their efficacy in poultry diets remains inconsistent. This meta-analysis quantitatively evaluated the effects of dietary microalgae supplementation on performance, egg quality, yolk fatty acid composition, and blood biochemistry in laying hens. Thirty-six peer-reviewed articles were retrieved from Scopus, ScienceDirect, PubMed, and Google Scholar following PRISMA guidelines, and effect sizes were calculated using weighted mean differences. Microalgae supplementation did not affect feed intake ( p  > 0.05) but significantly improved hen-day egg production, egg weight, egg mass, yolk weight, shell traits, and Haugh units ( p  < 0.05). Yolk pigmentation increased in color intensity and redness ( p  < 0.001) but decreased in lightness ( p  < 0.001). Microalgae enhanced yolk total n-3 PUFA, eicosapentaenoic acid, and docosahexaenoic acid ( p  < 0.001), while reducing n-6 PUFA and the n-6/n-3 ratio ( p  < 0.05). Blood total cholesterol, aspartate aminotransferase, and alanine aminotransferase concentrations decreased ( p  < 0.05). In conclusion, dietary microalgae supplementation augments laying performance, enhances egg quality and yolk pigmentation, fortifies yolk with beneficial n-3 fatty acids, and promotes liver health, highlighting its potential as a functional feed additive in layer diets.