Effect of a tomato extract-supplemented diet on egg yolk pigmentation and lycopene transfer efficiency

The aim of this research was to measure the ability of laying hens fed a tomato extract-supplemented diet to deposit dietary lycopene into the egg yolk, and to investigate the effects of lycopene on yolk pigmentation. Twenty Isa Brown hens were individually caged and fed two dietary treatments: 1) control diet (C) and 2) control diet + 0.08% (w/w) tomato extract dissolved in soybean oil (2% w/w) (TE). The tomato extract-supplemented diet provided a calculated lycopene level of 13 µg/g. Feed and water were provided ad libitum. Colorimetrical and HPLC analysis confirmed that the dietary lycopene was incorporated into the egg yolk at values ranging from 0.12 to 0.16 µg/g yolk (as is). Dietary tomato extract affected L*, a* and b* values of yolk and approximately 0.13% lycopene was transferred from the feed to the yolk. The data suggest that the TE diet resulted in a significant lycopene carry over and the intensity of egg yolk colour was influenced by dietary lycopene supplementation.