The Occurrence, Distribution, and Toxicity of High-Risk Ciguatera Fish Species (Grouper and Snapper) in Kiritimati Island and Marakei Island of the Republic of Kiribati.

Jingyi Zhu,Wai-Hin Lee,Taratau Kirata,Ki-Chun Yip,Leo-Lai Chan,Xiaowan Liu,Jiajun Wu,Shiwen Zhou

doi:10.3390/toxins14030208

Abstract

Ciguatera is one of the most widespread food poisonings caused by the ingestion of fish contaminated by ciguatoxins (CTXs). Snapper and grouper with high palatable and economic value are the primary food source and fish species for exportation in the Republic of Kiribati, but they are highly suspected CTX-contaminated species due to their top predatory characteristics. In this study, 60 fish specimens from 17 species of snappers and groupers collected from the Kiritimati Island and Marakei Island of the Republic of Kiribati were analyzed using mouse neuroblastoma (N2a) assay and liquid chromatography-tandem mass spectrometry (LC-MS/MS) to determine Pacific CTX-1, -2 and -3 (P-CTX-1, -2 and -3). The LC-MS/MS results show that CTXs were detected in 74.5% of specimens from Marakei Island and 61.5% of specimens from Kiritimati Island. The most toxic fish Epinephelus coeruleopunctatus from Marakei Island and Cephalopholis miniata from Kiritimati Island were detected as 53-fold and 28-fold P-CTX-1 equivalents higher than the safety level of 10 pg/g P-CTX-1 equivalents, respectively. CTX levels and composition profiles varied with species and location. The N2a results suggested that fish specimens also contain high levels of other CTX-like toxins or sodium channel activators. The distribution patterns for ciguatoxic fish of the two islands were similar, with fish sampled from the northwest being more toxic than the southwest. This study shows that groupers and snappers are high-risk species for ciguatera in the Republic of Kiribati, and these species can further be used as indicator species in ciguatera endemic areas for risk assessment.

Highlights

This article is an open access articleCiguatera is considered to be the most widespread and non-infectious seafood-borne illness, with 10,000 to 50,000 cases per year [1]
CTXs were detected in 10 fish species from Marakei Island, and total CTX levels in fish samples ranged from
A high frequency of ciguatoxic snappers and groupers were found in the Marakei and Kiritimati Islands, and most of them were not safe for human consumption

Summary

Introduction

This article is an open access articleCiguatera is considered to be the most widespread and non-infectious seafood-borne illness, with 10,000 to 50,000 cases per year [1]. Fish become ciguatoxic when they ingest ciguatoxins (CTXs) synthesized by bottom-dwelling dinoflagellates, such as Gambierdiscus and Fukuyoa [2]. These dinoflagellates frequently occur in shallow subtropical and tropical coastal habitats. CTXs enter the food web by herbivores grazing on macroalgae and other distributed under the terms and conditions of the Creative Commons. Substrates with dinoflagellates attached to their surfaces, causing CTXs to be bio-magnified and bio-transformed along with the food web [3]. The consumption of CTX contaminated fish may cause gastrointestinal disturbance (diarrhea, nausea, vomiting, abdominal pain), cardiovascular disturbance (bradycardia, hypotension), and nervous system disorders (perioral and systemic sensory abnormalities) after a toxic meal [4]. Repeated exposure to CTX may aggravate symptoms, and death may occur after eating the internal organs (e.g., viscera) of ciguatoxic fish [5]

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