[Eco layers feed: Are antioxidants and preservatives necessary?]

additif aux aliments des animaux aditivos de piensos agent de conservation agriculture biologique almacenamiento antioxidantes antioxidants antioxydant color colour compound feeds couleur eggs feed additives feed conversion efficiency gain de poids gallina ponedora ganancia de peso huevos layer chickens laying performance oeuf organic agriculture performance de ponte piensos compuestos poule pondeuse preservadores preservatives stockage storage weight gain