“…Last are synthetic sources, used in the poultry industry to manipulate the carotenoid content of egg yolk. Except apo-ester exclusively present in synthetic form ( EFSA FEEDAP Panel, 2009 ), other carotenoids are mainly chemically synthesized for commercial reasons and available from different companies. Among them are synthetic zeaxanthin ( EFSA FEEDAP Panel, 2009 ), synthetic canthaxanthin ( EFSA FEEDAP Panel, 2014 ), and synthetic lycopene ( An et al., 2019 ).…”