Role of the antioxidants in the protection against oxidative stress in cattle--nonenzymatic mechanisms (Part 2).

Antioxidative status consists of two mechanisms: nonenzymatic and enzymatic mechanisms. Nonenzymatic mechanisms are composed of antioxidants, scavengers of free radicals, transition metal ions, sequester transition metal ions, albumins, ceruloplasmin, and metallothioneins. On the other hand, enzymatic mechanisms are composed of superoxide dismutase (SOD), peroxidase, catalase and reductase. In cattle, characteristics of these mechanisms depend on the nutritional status of anti-oxidant minerals, especially copper, zinc, iron, selenium, silicon, and manganese. The nutritional status of the cattle in different regions of the world and in Poland is often characterised by the lack of these minerals; therefore, there is a great potential for changes in the activity of defence mechanisms against free radicals.