Marine algae as natural source of iodine in the feeding of freshwater fish - a new possibility to improve iodine supply of man

Different strategies have been developed to ensure a better iodine supply for man. The most common one is the iodisation of salt, but since the application is voluntary, it has not been effective enough. There still is a mild to moderate deficiency in the iodine intake of man of about 30 % in Germany [2, 6, 8]. Another strategy to fight iodine deficiency is to supplement animal feed with iodine (inorganic salt) and thus produce food high in iodine [5, 10]. Various marine algae are a rich source of iodine, e.g. Laminaria digitata, which contains about 4 g iodine per kg dry matter. Adding those iodine containing algae to the feed of pigs for example, leads to an evident increase in the iodine content of their meat [3]. Similar effects are shown for poultry [9]. Besides the large amount of iodine, the algae show several other advantages, such as a higher iodine stability and the occurrence of other essential trace elements and vitamins.