The available utilization of selenium from some inedible tissues of marine products-IV

The selenium distribution in the exoskeleton (abdominal pleuron) as an inedible tissue and the ordinary muscle of several species of shrimps (Kuruma prawn Marsupenaus japonocas, Northern shrimp Pandalus eous, Whiskered velvet shrimp Pleoticus muelleri and Black tiger prawn Penaeus monodon) in clustacea, which have been known to be useful as the scavenger of heavy metals, was investigated in order to clarify the possibility of the available utilization of selenium from those tissues, in relation with the mercury distribution involving the tissues. As a result, each selenium and mercury level in the exoskeleton of all subjected species, except Black tiger prawn, was about the same and low compared with that involving muscle, respectively. Moreover, from the selenium molar fraction involving exoskeleton, the low oxidation states of selenium species was almost predominant in all subjected species, as not in the case of involving ordinary muscle, suggesting that a little Se(VI) species as metabolized in living body after eating exists in the exoskeleton. On the other hand, 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, except Black tiger prawn, suggesting that the exoskeleton will be usually inedible but significantly safe tissue in which low levels of heavy metals such as mercury will tend to accumulate, as in the case of a preceding paper. These findings suggest that the available utilization of selenium will not be expected from the exoskeleton, including the improvement of the environment.