Change in the transfer profile of orally administered tetrodotoxin to non-toxic cultured pufferfish Takifugu rubripes depending of its development stage

► Tetrodotoxin (TTX) was administered to two different ages of Takifugu rubripes specimens by oral gavage. ► TTX content of the liver after 24 h in 15-month old fish was nearly 5-fold that in 6-month old fish. ► Total remaining TTX amount per individual was much higher in the 15-month old fish, most of which was found in the liver. ► Histologic observation suggests that the developmental stage of the liver differed between the two ages.