HISTOLOGICAL CHANGES PRODUCED IN THE GONAD OF Crassotrea gigas Th. AFTER IN VITRO EXPOSURE TO Se-IV

Publisher Summary This chapter describes experiments on histological changes produced in the gonad of Crassotrea gigas Th. after in vitro exposure to Se (IV). Lamellibranches are known to accumulate Se (IV). Gonad samples of oysters cultured on Streiff-Le Gall's solid medium showed a degenerative process of germinal cells. Gonads associated with cerebropleural ganglia of mature Mussels showed the preservation and evolution of germinal cells of male and female oysters. Same experiments were carried out on the same medium, but contaminated with Na 2 SeO 4 (Se VI) at concentrations of 25, 2.5, and 0.25 ppm. .Male or female gonads samples cultured alone or associated with ganglia showed a total destruction of their germinal cells when they are exposed to 25 and 2.5 ppm. Other organ cultured carried out with Se (VI) show no significant difference with the control cultures. These results show that no action of Se (IV) can be detected in experimental conditions under the threshold of concentration previously observed. Although mechanisms of Se (IV) toxicity are unknown, this metalloid would inhibit some key enzymes of the cellular metabolism.