engleski

Pigmentation Efficiency of Croatian Corn Hybrids in Egg Production

To achieve desirable egg yolk colour producers enhance laying hen’s diet with pigments, usually from synthetic origin. More recently, consumers have become more concerned about the use of synthetic additives in foods and feeds and interest in natural alternatives has increased. In Croatia, corn grain is the base of laying hen’s diet, but contribution of corn carotenoids to egg yolk colour was neglected. Therefore, aim of this research was to explore the pigmentation efficiency of corn grain hybrids in egg production. Three cages, each with three laying hens were allotted to one of the eight dietary treatments differentiated only in corn hybrid (56 % of diets) and fed for 63 days. There were no added synthetic pigments in the treatments. Total carotenoid content of the corn grain and egg yolk was quantified spectrophotometrically as β-carotene equivalents, while colour measurements of egg yolk were recorded instrumentally using a Minolta Chromameter (CR-410) in the CIE L* a* b* space, and subjectively by Roche yolk colour fan (RYCF). The level of total carotenoids in corn grain ranged from 17.32 to 31.52 mg/kg. Total carotenoids in egg yolks significantly differ (P<0.001) between dietary treatments. The RYCF, as conventional measure of yolk colour, ranged from 8 to 10 and correlated (r=0.81, P<0.001) with CIE a* value (redness). Both, the RYCF and a* value in egg yolk increased linearly with an increase in the level of total carotenoids in corn grain (b=0.0746, P<0.001 ; b=0.1856, P<0.001). This research showed that corn grain, without added pigments, in laying hen diet could provide adequate carotenoids supply for acceptable egg yolk colour. Better results (RYCF>10) could be achieved with higher portion of corn grain in the diet. In addition, the CIE a* value correlated well with RYCF scale and therefore could be used for more objective colour measurements of egg yolk.

egg yolk; carotenoids; colour; corn grain; poultry

nije evidentirano