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P. F. Surai and I. I. Kochish
carotenoid concentration in the chick liver dramatically decreases (Surai et al. 1998).
Interestingly, chicks obtained from carotenoid-depleted eggs are not able to effectively assimilate carotenoids from the diet to the same extent as those hatched from
carotenoid-rich eggs (Koutsos et al. 2003). Increased dietary carotenoid supplementation of the maternal diet was associated with elevated vitamin E concentrations in the
egg yolk, embryonic tissues and their increased resistance to oxidative stress (Surai
and Speake 1998; Surai et al. 2003). A combination of increased concentrations of
lycopene and lutein in the egg yolk was associated with elevated concentrations of
CoQ in the liver of the newly hatched quail (Karadas et al. 2006a).
20.5.4 Specific Roles of Canthaxanthin (CX) in Poultry
Breeder Nutrition
Among more than 1100 known carotenoids, CX has a special place as a carotenoid
with proven antioxidant and other biologically relevant functions. A great body of
evidence indicates that CX possesses high antioxidant activity that was shown in
various in vitro model systems as well as in animal experiments in vivo. To address
some important features of CX activity in breeders a study was conducted at the Scottish Agricultural College (SAC) (Surai et al. 2003) using 320 female broiler breeder
birds. Four treatments were compared, a low carotenoid control diet containing
<2 mg/kg total xanthophylls, and then test diets supplemented with either 3, 6, 12 and
24 mg/kg of a commercial CX product, (CAROPHYLL® Red 10% (Roche Vitamins
(UK) Ltd, Heanor, UK). The results of the trial showed that inclusion of CX into the
maternal diet caused a significant dose-dependent accumulation in the egg yolk. As
a result, egg yolk colour gradually changed from pale yellow in the control group
to dark red in the laying hens fed CX at 24 mg/kg. These results are in agreement
with previous observations from a similar trial using a carotenoid mixture (Surai and
Speake 1998). The most important finding of this study was related to a positive
effect of CX on vitamin E in the developing chicks. First of all, CX improved assimilation of γ-tocopherol from the diet and its transfer to the egg yolk. As a result, an
increased γ-tocopherol concentration was observed in the liver of the embryo at d 16
of the development. However, at later stages of the development, these differences
disappeared, probably due to a tocopherol-binding protein (Surai and Speake 1998).
Secondly, increased CX concentration in the egg yolk and embryonic tissues was
associated with higher α-tocopherol concentrations in the liver and plasma of 1-dold chicks. This could be a reflection of antioxidant interactions during embryonic
development. Indeed, if the CX that accumulated in tissues scavenged free radicals,
fewer radicals would be available to be scavenged by vitamin E. This could spare
some vitamin E and lead to its increased concentrations. There is also a possibility
that CX may take part in vitamin E recycling leading to increased vitamin E concentration. In fact, vitamin E recycling by β-carotene has been shown (Bohm et al.
1997). The synergistic effect of CX on vitamin E was seen in 7-d-old chicks, when
P. F. Surai and I. I. Kochish
carotenoid concentration in the chick liver dramatically decreases (Surai et al. 1998).
Interestingly, chicks obtained from carotenoid-depleted eggs are not able to effectively assimilate carotenoids from the diet to the same extent as those hatched from
carotenoid-rich eggs (Koutsos et al. 2003). Increased dietary carotenoid supplementation of the maternal diet was associated with elevated vitamin E concentrations in the
egg yolk, embryonic tissues and their increased resistance to oxidative stress (Surai
and Speake 1998; Surai et al. 2003). A combination of increased concentrations of
lycopene and lutein in the egg yolk was associated with elevated concentrations of
CoQ in the liver of the newly hatched quail (Karadas et al. 2006a).
20.5.4 Specific Roles of Canthaxanthin (CX) in Poultry
Breeder Nutrition
Among more than 1100 known carotenoids, CX has a special place as a carotenoid
with proven antioxidant and other biologically relevant functions. A great body of
evidence indicates that CX possesses high antioxidant activity that was shown in
various in vitro model systems as well as in animal experiments in vivo. To address
some important features of CX activity in breeders a study was conducted at the Scottish Agricultural College (SAC) (Surai et al. 2003) using 320 female broiler breeder
birds. Four treatments were compared, a low carotenoid control diet containing
<2 mg/kg total xanthophylls, and then test diets supplemented with either 3, 6, 12 and
24 mg/kg of a commercial CX product, (CAROPHYLL® Red 10% (Roche Vitamins
(UK) Ltd, Heanor, UK). The results of the trial showed that inclusion of CX into the
maternal diet caused a significant dose-dependent accumulation in the egg yolk. As
a result, egg yolk colour gradually changed from pale yellow in the control group
to dark red in the laying hens fed CX at 24 mg/kg. These results are in agreement
with previous observations from a similar trial using a carotenoid mixture (Surai and
Speake 1998). The most important finding of this study was related to a positive
effect of CX on vitamin E in the developing chicks. First of all, CX improved assimilation of γ-tocopherol from the diet and its transfer to the egg yolk. As a result, an
increased γ-tocopherol concentration was observed in the liver of the embryo at d 16
of the development. However, at later stages of the development, these differences
disappeared, probably due to a tocopherol-binding protein (Surai and Speake 1998).
Secondly, increased CX concentration in the egg yolk and embryonic tissues was
associated with higher α-tocopherol concentrations in the liver and plasma of 1-dold chicks. This could be a reflection of antioxidant interactions during embryonic
development. Indeed, if the CX that accumulated in tissues scavenged free radicals,
fewer radicals would be available to be scavenged by vitamin E. This could spare
some vitamin E and lead to its increased concentrations. There is also a possibility
that CX may take part in vitamin E recycling leading to increased vitamin E concentration. In fact, vitamin E recycling by β-carotene has been shown (Bohm et al.
1997). The synergistic effect of CX on vitamin E was seen in 7-d-old chicks, when