Toxicity and Molecular Identification of Green ToadfishLagocephalus lunarisCollected from Kyushu Coast, Japan

Abstract

Green toadfishLagocephalus lunarisinhabits tropical and subtropical seas and contains high tetrodotoxin (TTX) levels in the muscle as well as liver and gonad. In 2008 to 2009, food poisoning due to ingestingL. lunaisoccurred in Western Japan. Five specimens of green toadfish caught in Kyushu coast, Japan, were analyzed for toxicity, toxins, and species identification. All five specimens were toxic by bioassay. Comparing the maximum toxicity in tissues, ovary contained the most toxin (1810 mouse unit [MU]/g), followed by liver (341 MU/g), muscle (135 MU/g), skin (79 MU/g), and intestine (72 MU/g). Liquid chromatography/mass spectrometry analysis revealed that TTX was the major toxin. Nucleotide sequence analysis of the 16S rRNA gene fragment of muscle mitochondrial DNA indicated that partial sequences of PCR products of four specimens were identical with that ofL. lunaris. The sequence of one specimen was indistinguishable from that of the brown-backed toadfishLagocephalus wheeleri, a nontoxic species.