Abstract
The selenium distribution in the scale, the skin or the endothelium as inedible tissues and the ordinary muscle of several species of fish (Japanese horse mackerel Trachurus japonicus, Chub mackerel Scomber japonicus, Largehead hairtail Trichiurus lepturus and Doggertooth pike conger Muraenesox cinereus) which have generally been known as the special marine products from Oita Prefecture was investigated in order to clarify the possibility of the available utilization of selenium especially from inedible tissues, in relation with the mercury distribution involving the tissues. As results, both levels of selenium and mercury in the ordinary muscle of the subjected fish were higher than those from the other ocean areas. Each mercury and selenium level in those inedible tissues of all subjected species was about the same and high compared with that involving muscle, respectively. On the other hand, from the selenium molar fraction involving inedible tissues, the low oxidation states of selenium species was almost predominant in all subjected species, as not in the case of involving ordinary muscle. The Se/Hg (the molar ratio of selenium to mercury) as an indicator of the safety of marine products was also extremely high compared with that involving ordinary muscle, suggesting that the scale, the skin or the endothelium will be usually inedible but significantly safe tissue in which little levels of heavy metals such as mercury will tend to accumulate, as in the case of a preceding paper. These findings suggested that the available utilization of selenium will be expected from the scale, the skin or the endothelium as inedible tissues of fish regardless of inhabiting waters, including the improvement of the environment.
