Free astaxanthin-rich diets enhanced astaxanthin accumulation in egg yolks compared to esterified astaxanthin-rich diets.

As an oxycarotenoid with strong antioxidant properties, astaxanthin can considerably boost pigmentation and improve the nutritional value of eggs. The purpose of this study was to elucidate the comparative effects of different chemical structures of astaxanthin including free astaxanthin, monoester-enriched astaxanthin and diester-enriched astaxanthin on the nutritional enhancement of eggs within 20 days. The results showed that supplementation of free astaxanthin to laying hens was more effective in accumulating astaxanthin in egg yolks than supplementation with esterified astaxanthin. The retention rate of free astaxanthin was approximately 12.0 % at the plateau phase in egg yolk, while that of monoester-enriched and diester-enriched astaxanthin were 4.0 % and 2.5 %, respectively. Free astaxanthin possessed a high retention rate and pigmentation effect compared with esterified astaxanthin, which might provide a basis for astaxanthin enhancement in eggs and potential application in nutritional functional foods.