Carotenoids in Avian Nutrition and Embryonic Development. 1. Absorption, Availability and Levels in Plasma and Egg Yolk

Abstract

A review. Avian embryo development is associated with a progressive accumulation in certain tissues of lipids which are rich in polyunsaturated fatty acids (PUFA), making such tissues vulnerable to free radical attack and lipid peroxidation. Antioxidant systems are expressed in the embryonic tissues and are responsible for maintaining antioxidant protection during different stages of embryoonic development, in particular at hatching time when oxidative stress is highly pronounced (Surai, 1999). The antioxidant systems of the avian embryo are based on the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (Surai, 1999a ; Surai, 2000a), and fat-soluble and water-soluble natural antioxidants (Surai, 1999). Vitamin E is considered to be the main player in the antioxidant defence at the cellular and subcellular levels (Niki,1996). In recent years it has become evident that in the cell the association of vitamin E with other natural antioxidants which are able to recycle this vitamin from its oxidized form is the major biochemical mechanism in maintaining the efficiency of antioxidant defence (Surai, 1999; Surai, 2000).