Egg Yolk Colour Depending upon the Composition of the Feeding Mixture for Laying Hens

Abstract

The aim of this study was to verify the possibility of replacement of fish meal by specially treated meal made of yellow lupin seed in relation to the yolk colour. The experiment was performed with 72 laying hens divided into two groups. The experimental group including 36 laying hens received a feeding mixture containing meal made of yellow lupin seed (the JUNO variety) which replaced fish meal used as an animal protein component in feeding mixtures in the control group. Samples of eggs were collected monthly in the course of seven months to determine the colour of egg yolk.Yolk colour was determined by the spectrophotometric method using the CIELAB system. Measurement with the exclusion of gloss was carried out using a portable spectrophotometer. The average values of parameter L* decreased significantly (α = 0.05), which confirmed the darkening of eggs. Parameters a* showed a significant increase (ANOVA α = 0.01), whereas the differences in the individual months ranged from 1.1 to 3.9. Yolk had distinct red-orange colour. Parameters b* did not show significant differences, however, the yolk tended to have an intensive yellow colour.The presence of yellow lupin seed meal in the feeding mixture resulted in a more distinct yellowred colour of egg yolk.

The effect of addition of yellow lupin seeds (<i>Lupinus luteus</i> L.) to laying hen diets on performance and egg quality parameters

“…Not only higher values of egg content pH and of HU units were determined, but also there was a decrease in the thickness, strength and share of egg shell in the egg weight. Dvořák et al (2007) observed improved egg quality parameters after adding lupin to hen feed. Watkins and Mirosh (1987) confirmed the lack of significant differences in the HU units of eggs among treatments of hens fed diets containing 10, 15, 20, 25 and 30% white lupin seeds, but 30% share of this feed component in the diet led to a decrease in egg production.…”

“…Nevertheless, in our study, the presence of yellow lupin seeds in laying hen diets improved some egg quality parameters. Sikder et al (1998) and Dvořák et al (2007), and also many other authors, have underlined the fact that dietary composition significantly influences yolk colour -an important egg quality index for consumers. In our experiment, significant improvement of yolk colour (La Roche scale) was obtained as an effect of the rise in yellow lupin seeds content in the diets and increased levels from 1.59 (in group with 10% yellow lupin seeds addition) to 3.97 (in group with 25% yellow lupin seeds addition) in 1 kg of feed mixture.…”

“…The effect of raw materials on yolk colour is a well-known phenomenon: maize contains lutein and zeaxanthin at concentrations of 20 to 25 mg of xanthophyll · kg −1 , carrot meal contains 54 to 65 mg of xanthophyll · kg −1 (Sikder et al, 1998;Dvořák et al, 2007). Maize silage (grains and cobs) exert a positive effect on yolk colour when included in diets for laying hens.…”

Photocolorimetric determination of yolk colour in relation to selected quality parameters of eggs

“…All egg yolk measurements were done automatically three times. The resulting value was the average of the three measured values 8, 9. The results for parameters L *, a *, b * were divided into categories.…”

Variation in Egg Yolk Colour in Different Systems of Rearing Laying Hens

“…The feed mixtures only consisted of plant-based components. Meal made from the yellow lupine variety JUNO seeds, which is also an important source of plant pigments (Dvořák et al 2007), was one of the components. No artificial colourings were used, natural pigments originated from feed components.…”