Tissue-specific antioxidant profiles and susceptibility to lipid peroxidation of the newly hatched chick

The hatching process is characterized by a range of adaptive changes, and a newly hatched chick is considered as an intermediate stage between prenata l and postnatal development. The aim of the present study was to evaluate t he characteristic relationships between tissue-specific fatty acid composit ion and antioxidant protection in newly hatched chicks. Liver, yolk sac mem brane, heart, kidney, lung, and four brain regions (cerebrum, cerebellum, s tem, and optic lobes) were collected. Fatty acid composition of total lipid s and phosphoglycerides, alpha-tocopherol, lutein, ascorbic acid, reduced g lutathione, and the activities of Mn- and Cu,Zn-superoxide dismutase (SOD) and Se-dependent and non-Se-glutathione peroxidase (GSH-Px), and catalase ( CAT) were determined. The levels of Fe, Cu, Zn, and Mn as well as tissue su sceptibility to lipid peroxidation were also studied. The tissues of the ne wly hatched chick showed distinctive features in fatty acid profiles, antio xidant accumulation, and susceptibility to lipid peroxidation. The brain cl early displayed the greatest susceptibility to spontaneous and Fe-stimulate d lipid peroxidation, was highly unsaturated and contained very low levels of vitamin E, no detectable carotenoids, low GSH-Px, and low CAT activity. At the same time, the brain was characterized by high ascorbic acid concent ration and comparatively high SOD activity. It was suggested that in postna tal development, antioxidant enzymes presumably play the major role in anti oxidant protection of the chick tissues.