Co-occurrence of tetrodotoxin and saxitoxin in Cambodian marine pufferfish Takifugu oblongus

Abstract

The toxicity and toxin profiles of the marine pufferfish Takifugu oblongus were investigated from fish collected from Sihanouk Ville, one of the main regions where pufferfish poisonings (PFP) have occurred in Cambodia. Standard mouse bioassay revealed that all specimens collected were toxic, and their toxicities were mainly contained in the ovary. Toxicities ranged from 10 to 132 mouse units (MU) g⁻¹, much higher than the regulatory limit for human consumption (10 MU g⁻¹). The skin, muscle, liver, viscera and testis toxicities were all below 20 MU g⁻¹. Toxic principles in the species were identified as tetrodotoxin (TTX) as the main component and saxitoxin (STX) as a minor. It was confirmed that T. oblongus is a hazardous species that is unsafe for human consumption and that TTX is the likely cause of pufferfish poisonings in Sihanouk Ville. This is the first report of the occurrence of STX both in the indigenous pufferfish and in Cambodian waters.