Tetrodotoxin in bivalve mollusks: An integrated study towards the comprehension of the influencing factors of a newly native phenomenon

Pietro Antonelli; Arianna Peruzzo; Marzia Mancin; Aurora Boscolo Anzoletti; Sonia Dall'Ara; Massimiliano Orsini; Paola Bordin; Giuseppe Arcangeli; Bruno Zanolin; Lisa Barco; Carmen Losasso

doi:10.1016/j.chemosphere.2023.139682

Tetrodotoxin in bivalve mollusks: An integrated study towards the comprehension of the influencing factors of a newly native phenomenon

Chemosphere. 2023 Oct:339:139682. doi: 10.1016/j.chemosphere.2023.139682. Epub 2023 Jul 30.

Affiliations

¹ Microbial Ecology and Microorganisms Genomics Laboratory, Istituto Zooprofilattico Sperimentale Delle Venezie, PD, Viale Dell'Università 10, 35020, Legnaro, Italy.
² National Reference Laboratory for Marine Biotoxins, Fondazione Centro Ricerche Marine, Viale A. Vespucci 2, 47042, Cesenatico, FC, Italy.
³ Specialistic Aquatic Animal Health Centre, Istituto Zooprofilattico Sperimentale Delle Venezie, PD, Viale Dell'Università 10, 35020, Legnaro, Italy.
⁴ Regional Environmental Protection Agency of Friuli Venezia Giulia, ARPA FVG, Via Cairoli 14, 33057, Palmanova, UD, Italy.
⁵ Microbial Ecology and Microorganisms Genomics Laboratory, Istituto Zooprofilattico Sperimentale Delle Venezie, PD, Viale Dell'Università 10, 35020, Legnaro, Italy. Electronic address: closasso@izsvenezie.it.

PMID: 37527741
DOI: 10.1016/j.chemosphere.2023.139682

Abstract

Tetrodotoxins (TTXs) are potent neurotoxins named after the Tetraodontidae fish family. The ingestion of TTX-contaminated flesh can cause neurotoxic symptoms and can lead to death. In 2017 symptoms the European Food Safety Authority (EFSA) recognized the threat to food safety resulting from TTX exposure via food consumption and, thus, proposed a safety limit of 44 μg/kg of TTX in marine gastropods and bivalves. To date, however, TTXs have not yet been included in the list of biotoxins to be monitored within the European Union, even though, in a few cases, levels of TTX found were higher than the EFSA limit. The origin of TTX production is debated and the roles of both biotic and abiotic factors on TTX-mediated toxic events remain unclear. In order to meet these knowledge requests the present study was aimed to investigate the role of seawater temperature, pH, water conductivity, and oxygen saturation, along with the marine phytoplankton community and the bacterial community of mussels and oysters on the accumulation of TTX and analogues in the bivalves. Abiotic parameters were measured by means of a multi-parametric probe, phytoplankton community was analyzed by optic microscopy while microbial community was described by amplicon metataxonomic sequencing, TTXs concentration in the collected matrices were measured by HILIC-MS/MS. A possible role of seawater pH and temperature, among the investigated abiotic factors, in regulating the occurrence of TTXs was found. Regarding biotic variables, a possible influence of Vibrio, Shewanella and Flavobacteriaceae in the occurrence of TTXs was found. Concurrently, Prorocentrum cordatum cell numbers were correlated to the incidence of TTX in mussels. The results herein collected suggest that environmental variables play a consistent part in the occurrence of TTX in the edible bivalve habitats, and there are also indications of a potential role played by specific bacteria taxa in association with phytoplankton.

Keywords: Adriatic sea; Marine poisons; TTX.

MeSH terms

Animals
Bivalvia*
Comprehension
Neurotoxins
Phytoplankton
Tandem Mass Spectrometry*
Tetrodotoxin / toxicity

Substances

Tetrodotoxin
Neurotoxins