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

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.

Preparation of Ciguatoxin Reference Materials from Canary Islands (Spain) and Madeira Archipelago (Portugal) Fish

“…The primary materials used in this work consisted of muscle and liver tissues from fish that were pre-screened for CTX activity in the N2a cell assay. The selection of specimens for extraction was limited to those with higher concentrations of C-CTX1 as previously determined in [24,25]. The muscle tissues (50 kg) were pooled from specimens of amberjack (Seriola sp.…”

“…As indicated above, the method used for the determination of RMR is described by Estevez et al [24] 3. Results and Discussion 3.1.…”

“…Furthermore, the concentration of CTXs in fish tissue from the NE Atlantic is generally very low (<1 µg/kg), which together lead to poor recoveries. These limitations resulted in the decision to include parallel extractions of fish livers, in which the concentration of the CTXs is much higher [24], to increase CTX yield. However, the higher complexity of the liver matrix required additional purification steps for the isolation of CTXs.…”

Natural Polyether Ionophores and Their Pharmacological Profile

“…Ciguatera fish poisoning (CFP) is currently the most common marine biotoxin food poisoning worldwide, associated with human consumption of circumtropical fish and marine invertebrates that are contaminated with ciguatoxins. Ciguatoxins are a potent sodium channel activator and contain neurotoxins that pose a health hazard at very low concentrations [ 89 , 90 ].…”

“…The use of fish from the tropics, which are contaminated with ciguatoxins, leads to various diseases characterized by neurological, cardiovascular, and gastrointestinal disorders, and the toxins themselves demonstrate the ability to cause persistent activation of voltage-gated sodium channels, which increases the excitability of neurons and the release of neurotransmitters. There is currently no medically approved treatment for ciguatera [ 89 , 90 , 91 ].…”