Zrno kukuruza najzastupljenije je krmivo u hranidbi peradi, a ujedno i jedina žitarica sa značajnim sadržajem karotenoida. Doprinos karotenoida kukuruza boji žutanjka se zanemaruje unatoč visokom udjelu u hranidbi nesilica te je cilj ovog istraživanja bio ispitati utjecaj karotenoidnog profila istraživanih hibrida kukuruza na promjenu boje žutanjka nesilica hranjenih krmnim smjesama bez dodanih pigmenata. Hranidbeni su se tretmani razlikovali jedino u hibridu kukuruza te su imali 60% zrna pet poznatih hibrida (Bc 572, Kekec, Mejaš, Riđan i Pajdaš) te jednog nepoznatog porijekla kao kontrole. Ukupno 90 nesilica hibrida Tetra, po tri u svakom kavezu, nakon razdoblja čišćenja je raspoređeno nasumičnim rasporedom na šest hranidbenih tretmana. Jaja su sakupljana svaka tri dana do stabilizacije boje, a nakon toga jednom tjedno do kraja 12. tjedna. U svim uzorcima određena je boja prema CIE L*a*b*. Boja žutanjka jaja svih tretmana se stabilizirala 10. dana pokusnog razdoblja, a a* je parametar boje koji je bio najosjetljiviji na promjene boje žutanjka. Boja hranidbenih tretmana je bila stabilna do 70. dana pokusnog razdoblja kada je a* počeo opadati, dok je kod kontrole a* počeo opadati već nakon 56. dana. 42. dana pokusa parametri boje svih tretmana bili su u sljedećim rasponima: L* = 65,7 – 68,8, a* = 8,2 – 13,5 i b* = 65,5 – 67,4. Od istraživanih hibrida, najuspješniji (najviša a*) bio je Bc 572, ujedno i hibrid s najvećim sadržajem zeaksantina, β-kriptoksantina i β-karotena.

Maize grain is most commonly used feed in poultry nutrition and the only cereal with significant carotenoid content. The contribution of maize carotenoids to the egg yolk colour id neglected despite high content in hens’ diet, and this study aimed to investigate the effect of carotenoid profile from different maize hybrids on the yolk colour change without added pigments in diets. Dietary treatments differed only in maize hybrid had 60% of grain from five known hybrids (Bc 572, Kekec, Mejaš, Riđan and Pajdaš) and one unknown as a control. A total of 90 Tetra hybrid hens, three in each cage, were allotted to six dietary treatments in randomized block design. Eggs were collected every three days until colour stabilisation, and then once weekly until the 12th week. In all egg samples, the colour was determined according to the CIE L*a*b* colour space. Egg yolk colour from all dietary treatments stabilised after the 10th day of trial period, and a* was the most sensitive parameter to the changes in egg yolk colour. Egg yolk colour of known maize hybrids was table until the 70th day of trial period while it started declined after 56th day in control. The 42nd day of trial period, colour parameters were as follows: L* = 65,7 – 68,8, a* = 8,2 – 13,5 and b* = 65,5 – 67,4. From tested hybrids, the most successful (the highest a* value) was Bc 572, the hybrid with the highest content of zeaxanthin, β-cryptoxanthin and β-carotene.