524
P. F. Surai and I. I. Kochish
20.5.2 Skin Pigmentation
It is well known that skin colour plays an important role in consumer acceptance
of broilers and in some countries such as Mexico consumers demand chickens with
an extreme yellowness of the skin (Ornelas 1997; Pena et al. 2004). It is important to mention that skin of broilers grown on the typical commercial diets is characterised by low yellowish colour, but it can be manipulated by usage of dietary
carotenoid pigments which are deposited in the skin and fat (Perez-Vendrell et al.
2001; Castaneda et al. 2005). There is a range of natural and synthetic sources
of pigments which can be used in commercial broiler feed. In particular, feed
ingredients with high carotenoid content include yellow corn, corn gluten meal,
dehydrated alfalfa meal, algae meals, marigold meals and concentrated extracts
from marigold meals or alfalfa meal (Marusich and Bauernfeind 1981). Among
the synthetic pigments, canthaxanthin, apo-ester, and others have been developed
and successfully used commercially. It is necessary to underline that the effectiveness of a particular pigmenting substance/feed ingredient for poultry products (skin)
colouration depends on the chemical nature, level and availability of the xanthophylls
in the source (Delgado-Vargas 1997).
20.5.3 Poultry Breeder Nutrition
Natural carotenoids have been included into the category of antioxidants (Surai 2002,
2012a, b). In fact, carotenoids are working in the body as an integral part of the
antioxidant system, providing recycling other antioxidants including vitamin E and
affecting various transcription factors including Nrf2 and NF-κB.
Poultry diet formulations differ across the world but maize-based diets rich in
carotenoids are common in the USA (Ensminger 1980) and wheat-barley diets
comparatively low in carotenoids, are widely used in Europe (Hocking and Bernard
1997). Maize is a good source of zeaxanthin and lutein but wheat and other feed
ingredients are poor sources of carotenoids, especially zeaxanthin (Marusich and
Bauernfeind 1981). The carotenoid concentrations and composition in the egg yolk
depend on their feed content (Surai and Speake 1998). We conducted a comparative
study of the effect of maize-based diet (M) and wheat-based diet (W) on the egg
composition and chicken embryonic development (Surai and Sparks 2001). Both
major carotenoids of the egg yolk lutein and zeaxanthin were significantly enhanced
in the egg yolk of the M-group. In fact, the zeaxanthin concentration in the egg
yolk was enhanced compared with lutein, reflecting the differences in the carotenoid
composition of the feed. Carotenoids were shown to be transferred from egg yolk to
embryonic tissue more effectively in the M-group than in the W-group. For example,
the difference in total carotenoids in the egg yolk between the 2 groups was 2-fold but
in the liver of the newly hatched chicks in the M-group the carotenoid concentration
was more than 3-fold higher than in the W-group. Similar differences were observed
P. F. Surai and I. I. Kochish
20.5.2 Skin Pigmentation
It is well known that skin colour plays an important role in consumer acceptance
of broilers and in some countries such as Mexico consumers demand chickens with
an extreme yellowness of the skin (Ornelas 1997; Pena et al. 2004). It is important to mention that skin of broilers grown on the typical commercial diets is characterised by low yellowish colour, but it can be manipulated by usage of dietary
carotenoid pigments which are deposited in the skin and fat (Perez-Vendrell et al.
2001; Castaneda et al. 2005). There is a range of natural and synthetic sources
of pigments which can be used in commercial broiler feed. In particular, feed
ingredients with high carotenoid content include yellow corn, corn gluten meal,
dehydrated alfalfa meal, algae meals, marigold meals and concentrated extracts
from marigold meals or alfalfa meal (Marusich and Bauernfeind 1981). Among
the synthetic pigments, canthaxanthin, apo-ester, and others have been developed
and successfully used commercially. It is necessary to underline that the effectiveness of a particular pigmenting substance/feed ingredient for poultry products (skin)
colouration depends on the chemical nature, level and availability of the xanthophylls
in the source (Delgado-Vargas 1997).
20.5.3 Poultry Breeder Nutrition
Natural carotenoids have been included into the category of antioxidants (Surai 2002,
2012a, b). In fact, carotenoids are working in the body as an integral part of the
antioxidant system, providing recycling other antioxidants including vitamin E and
affecting various transcription factors including Nrf2 and NF-κB.
Poultry diet formulations differ across the world but maize-based diets rich in
carotenoids are common in the USA (Ensminger 1980) and wheat-barley diets
comparatively low in carotenoids, are widely used in Europe (Hocking and Bernard
1997). Maize is a good source of zeaxanthin and lutein but wheat and other feed
ingredients are poor sources of carotenoids, especially zeaxanthin (Marusich and
Bauernfeind 1981). The carotenoid concentrations and composition in the egg yolk
depend on their feed content (Surai and Speake 1998). We conducted a comparative
study of the effect of maize-based diet (M) and wheat-based diet (W) on the egg
composition and chicken embryonic development (Surai and Sparks 2001). Both
major carotenoids of the egg yolk lutein and zeaxanthin were significantly enhanced
in the egg yolk of the M-group. In fact, the zeaxanthin concentration in the egg
yolk was enhanced compared with lutein, reflecting the differences in the carotenoid
composition of the feed. Carotenoids were shown to be transferred from egg yolk to
embryonic tissue more effectively in the M-group than in the W-group. For example,
the difference in total carotenoids in the egg yolk between the 2 groups was 2-fold but
in the liver of the newly hatched chicks in the M-group the carotenoid concentration
was more than 3-fold higher than in the W-group. Similar differences were observed