Ciguatoxin Detection in Flesh and Liver of Relevant Fish Species from the Canary Islands.

María José Ramos-Sosa,Ana Gago-Martínez,María José Caballero,Daniel Padilla,Jorge Diogène,Andres Sanchez-Henao,Pablo Estévez,José Luís Martín-Barrasa,Natalia García-Álvarez,Fernando Real,Freddy Silva Sergent

doi:10.3390/toxins14010046

Abstract

The Canary Islands are a ciguatoxin (CTX) hotspot with an established official monitoring for the detection of CTX in fish flesh from the authorised points of first sale. Fish caught by recreational fishermen are not officially tested and the consumption of toxic viscera or flesh could lead to ciguatera poisoning (CP). The objectives of this study were to determine the presence of CTX-like toxicity in relevant species from this archipelago, compare CTX levels in liver and flesh and examine possible factors involved in their toxicity. Sixty amberjack (Seriola spp.), 27 dusky grouper (Epinephelus marginatus), 11 black moray eels (Muraena helena) and 11 common two-banded seabream (Diplodus vulgaris) were analysed by cell-based assay (CBA) and Caribbean ciguatoxin-1 (C-CTX1) was detected by liquid chromatography mass spectrometry (LC-MS/MS) in all these species. Most of the liver displayed higher CTX levels than flesh and even individuals without detectable CTX in flesh exhibited hepatic toxicity. Black moray eels stand out for the large difference between CTX concentration in both tissues. None of the specimens with non-toxic liver showed toxicity in flesh. This is the first evidence of the presence of C-CTX1 in the common two-banded seabream and the first report of toxicity comparison between liver and muscle from relevant fish species captured in the Canary Islands.

Highlights

Ciguatoxins (CTXs) are natural marine lipophilic toxins which may cause ciguatera poisoning (CP) in humans
The distribution of individual toxin concentrations obtained by cell-based assay (CBA) in the liver and flesh of the different species are represented in a box plot (Figure 1), as well as the liver versus flesh CTX concentration ratio (Figure 2)
They found that the liver presented a minimum of 13-fold higher concentration of CTX than flesh and, in Gymnothorax funebris, they observed a maximum of a 114-fold increase in liver than in muscle, comparable with the maximum found in this study in a black moray eel which presented 124 times more toxicity in the liver than in the flesh

Summary

Introduction

Ciguatoxins (CTXs) are natural marine lipophilic toxins which may cause ciguatera poisoning (CP) in humans. The EuroCigua project, co-funded by the European Food Safety Authority (EFSA) and the University of Las Palmas de Gran Canaria (ULPGC), focused on the characterisation of the risk of CP in Europe. This project highlighted the importance of the Canary Islands for the presence of CTXs in algae and fish, and revealed that amberjack (Seriola spp.), dusky grouper (Epinephelus marginatus), moray eel (family Muraenidae), and the common two-banded seabream (Diplodus vulgaris) are relevant species that accumulate toxins in their tissues

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