Iron is utilized in various enymes including cytochromes, catalases, peroxidases and dehydrogenases. Iron absorption may be depressed by high levels of phosphates, calcium, phytates, copper and zinc. Sources of iron include blood meal, dried distillers solubles, crab meal, fish solubles and fish meal. Supplemented iron sources include ferrous gluconate and ferric sulfate; however, there may not be a need to supplement iron. Recommended level of iron in commercial feeds is 300 ppm (Akiyama et al., 1992).