20 Carotenoids in Aviculture
517
20.2 Chemical Structure and Properties
All carotenoids may be derived from the acylic C 40 H 56 structure having a long central
chain of conjugated double bonds (Pfander 1992) and they can be described by the
general formula C 40 H 56 O n , where n is 0–6; hydrocarbons (n = 0) are called carotenes,
whereas oxygenated carotenoids (n = 1–6) are termed xanthophylls (Castenmiller
and West 1998). Carotenoids are based upon the same C40 isoprenoid skeleton, which
is modified by cyclisation, addition, elimination, rearrangement and substitution
(Rice-Evans et al. 1997).
20.3 Molecular Mechanisms of Carotenoid Action
in Animals
It is well known that carotenes are precursors of vitamin A and this function has
been well defined. However, less than 10% of known carotenoids can be converted to
vitamin A. Clearly defined roles for non-provitamin carotenoids have still to be definitively established (Thurnham and Northrop-Clewes 1999), but evidence is emerging
for several important functions. These include:
• antioxidant activities (Surai et al. 2001a, b; Surai 2002, 2012a, b; Surai et al. 2016;
Xavier and Pérez-Gálvez 2016; Bahonar et al. 2017; Weaver et al. 2018; Ribeiro
et al. 2018);
• the promotion of cell differentiation (McDevitt et al. 2005; Wójcik et al. 2008;
Nagao 2009; Bolhassani et al. 2014; Takahashi et al. 2018; Xie et al. 2019);
• regulation of cell proliferation (Zhang et al. 2011a, b Liu et al. 2013; Barzegari
and Pavon-Djavid 2014; Bolhassani et al. 2014; Gupta et al. 2016; Li et al. 2018a,
b; Dutta et al. 2018);
• regulation of intracellular communication via gap junctions (Stahl et al. 2002;
Livny et al. 2002; Stahl and Sies 2005; Leone et al. 2010; Kim et al. 2016);
• regulation of cellular activity/levels of the detoxifying enzymes (De Flora et al.
1999; Stahl et al. 2002; Rühl et al. 2004; Ben-Dor et al. 2005);
• enhancement of immune function (Moller et al. 2000; Sun et al. 2014; Babin et al.
Babin et al. 2010, 2015; Hosseini-Vashan et al. 2016; George et al. 2017; Milani
et al. 2017; Toti et al. 2018);
• Nrf2 upregulation (Zhao et al. 2017; Li et al. 2018b; Yu et al. 2018; Chang et al.
2018; Yang et al. 2018; Xie et al. 2018; Zhu et al. 2018; Hu et al. 2018; Lin et al.
2018; Niu et al. 2018; Xue et al. 2019);
• NF-κB downregulation (Sahin et al. 2017; Zhao et al. 2017; Shi et al. 2018; Barros
et al. 2018; Sung and Kim 2018; Chang et al. 2018; Icel et al. 2019; Li et al. 2019);
• natural colorants providing coloration to birds, reptiles, amphibians, fish and
various invertebrates (Surai 2002);
• cell membrane stabilisers in molluscs (Surai 2002).
517
20.2 Chemical Structure and Properties
All carotenoids may be derived from the acylic C 40 H 56 structure having a long central
chain of conjugated double bonds (Pfander 1992) and they can be described by the
general formula C 40 H 56 O n , where n is 0–6; hydrocarbons (n = 0) are called carotenes,
whereas oxygenated carotenoids (n = 1–6) are termed xanthophylls (Castenmiller
and West 1998). Carotenoids are based upon the same C40 isoprenoid skeleton, which
is modified by cyclisation, addition, elimination, rearrangement and substitution
(Rice-Evans et al. 1997).
20.3 Molecular Mechanisms of Carotenoid Action
in Animals
It is well known that carotenes are precursors of vitamin A and this function has
been well defined. However, less than 10% of known carotenoids can be converted to
vitamin A. Clearly defined roles for non-provitamin carotenoids have still to be definitively established (Thurnham and Northrop-Clewes 1999), but evidence is emerging
for several important functions. These include:
• antioxidant activities (Surai et al. 2001a, b; Surai 2002, 2012a, b; Surai et al. 2016;
Xavier and Pérez-Gálvez 2016; Bahonar et al. 2017; Weaver et al. 2018; Ribeiro
et al. 2018);
• the promotion of cell differentiation (McDevitt et al. 2005; Wójcik et al. 2008;
Nagao 2009; Bolhassani et al. 2014; Takahashi et al. 2018; Xie et al. 2019);
• regulation of cell proliferation (Zhang et al. 2011a, b Liu et al. 2013; Barzegari
and Pavon-Djavid 2014; Bolhassani et al. 2014; Gupta et al. 2016; Li et al. 2018a,
b; Dutta et al. 2018);
• regulation of intracellular communication via gap junctions (Stahl et al. 2002;
Livny et al. 2002; Stahl and Sies 2005; Leone et al. 2010; Kim et al. 2016);
• regulation of cellular activity/levels of the detoxifying enzymes (De Flora et al.
1999; Stahl et al. 2002; Rühl et al. 2004; Ben-Dor et al. 2005);
• enhancement of immune function (Moller et al. 2000; Sun et al. 2014; Babin et al.
Babin et al. 2010, 2015; Hosseini-Vashan et al. 2016; George et al. 2017; Milani
et al. 2017; Toti et al. 2018);
• Nrf2 upregulation (Zhao et al. 2017; Li et al. 2018b; Yu et al. 2018; Chang et al.
2018; Yang et al. 2018; Xie et al. 2018; Zhu et al. 2018; Hu et al. 2018; Lin et al.
2018; Niu et al. 2018; Xue et al. 2019);
• NF-κB downregulation (Sahin et al. 2017; Zhao et al. 2017; Shi et al. 2018; Barros
et al. 2018; Sung and Kim 2018; Chang et al. 2018; Icel et al. 2019; Li et al. 2019);
• natural colorants providing coloration to birds, reptiles, amphibians, fish and
various invertebrates (Surai 2002);
• cell membrane stabilisers in molluscs (Surai 2002).