[Effect of A- and E-vitamin additives in laying feed on vitamin content in eggs]

additif aux aliments des animaux aditivos de piensos aliment pour animaux colorant alimentaire colorantes alimentarios egg yolk eggs feathers feed additives feeds food colourants gallina ponedora huevos jaune d'oeuf layer chickens laying performance noruega norway oeuf performance de ponte piensos plumas plume poule pondeuse retinol teneur en vitamines vitamin content vitamin e vitamina e vitamine e yema de huevo