Elsevier

Toxicon

Volume 51, Issue 5, April 2008, Pages 780-786
Toxicon

Paralytic shellfish poisoning toxin profile of mussels Perna perna from southern Atlantic coasts of Morocco

https://doi.org/10.1016/j.toxicon.2007.12.004 Get rights and content

Abstract

During the monitoring programme of harmful algal blooms established along the south Atlantic coast of Morocco, a bimonthly determination of harmful algae and phycotoxins analysis in Perna perna was carried out from May 2003 to December 2004. Results of mouse bioassay (in organs and whole flesh) showed a seasonal evolution of paralytic shellfish poisoning (PSP) toxin. The mussel's contamination was associated with the occurrence in water of Alexandrium minutum.

The PSP toxin profile obtained with high-performance liquid chromatography (HPLC/FD) revealed the dominance of gonyautoxins GTX2 and GTX3 and a minority of GTX1, GTX4 and saxitoxin (STX). This profile explains that the toxicity was mainly associated with A. minutum.

Introduction

The contamination of shellfish by paralytic shellfish poisoning (PSP) is a real worldwide threat for public health and has a negative effect on shellfish farming (Hallegraeff, 1995).

Currently, there are at least 21 PSP known compounds. These toxins are separated into four groups: carbamate (saxitoxin (STX), neosaxitoxin (neoSTX) and gonyautoxins (GNTX1-4); N-sulpho-carbamoyl (GNTX5-6, C1-4); decarbamoyl (dc-) (dcSTX, dcneoSTX and dcGNTX1-4) and deoxydecarbamoyl (doh) (doSTX, doneoSTX and doGNTX1). Generally, the PSP toxins are synthesized by several Alexandrium species (Schantz et al., 1966), Gymnodinium catenatum (Oshima et al., 1987) and Pyrodinium bahamense var. compressum (Harada et al., 1982). The specie Alexandrium minutum was identified as the organism responsible for the PSP events in several countries in Ireland (Touzeta et al., 2007), Italy, UK, Portugal, Norway, France and Spain (FAO, 2004).

Morocco with important natural beds of mussels and some areas of aquaculture is not spared from this problem. In the Mediterranean coast, the permanent PSP toxicity in bivalve shellfish has been associated with G. catenatum (Taleb et al., 2001), but in the North Atlantic coasts, G. catenatum and A. minutum are both implied in the PSP toxicity of 1994 and 1998. The level of this toxicity was superior to the maximum permissible level (MPL) (Taleb et al., 2003). In 1982, 51 persons were intoxicated following the ingestion of Agadir's mussels (Bourhili, 1982). In Morocco, the MPL (80 mg STX equivalents/100 g shellfish) is similar to that set by the US Food and Drug Administration (FDA, 1997).

This study reports the first determination of PSP toxin profile of Perna perna from the southern Atlantic coasts of Morocco. The temporal evolution of Alexandrium spp. and Gymnodinium spp. and the accumulation of this toxin in organs and in whole flesh were reported in this paper.

Section snippets

Materials and methods

A monitoring programme was carried out bimonthly from May 2003 to December 2004 at three mussels beds regions along the South Atlantic Moroccan shore: Tifnit (Agadir) 30°11′718N-09°38′46W; Akhfenir (Laayoune) 28°05′34N-12°06′366W and Oum labouir (Dakhla) 23°46′92N-15°55′59W (Fig. 1). The geographical location of sampling areas was determined using the Global Positioning system. More than 120 water samples were collected in surface waters at high tide. Mussels (P. perna) samples were collected

Monitoring data

The samples of seawater analysed from Tifnit, Akhfenir and Oumlabouir contained micro algae belonging to two genera: Alexandrium and Gymnodinum. (Fig. 2) The specie A. minutum was observed and identified during the detection of PSP toxin in the mussels of three regions.

In Akhfenir surface waters, Alexandrium spp. and Gymnodinum spp were recorded in 2003 and 2004 at the same periods, May/June and September/November (Fig. 2A). The maximum of the concentrations of Alexandrium spp varied between

Discussion

This study reports that the PSP toxin in Perna perna from south Atlantic of Morocco was not exceeding the sanitary threshold. The maximum of toxicity and the majority of PSP components were detected principally in digestive glands, this organ was the most contaminated organ and the other tissues contributed weakly to the total toxicity; the same result was reported by Bricelj and Shumway (1998).

However, a gradient of toxins accumulation by different organs was established: digestive

Acknowledgments

We acknowledge Mr. Abdellatif Berraho, Director of the National Institute of Fisheries Research (INRH), for his support, Mr. Bernoussi, Mr. El Attar and the staff of LSSL Dakhla and Laâyoune. The HPLC runs were performed in the laboratory of Professor Bernd Luckas at the Friedrich Schiller University in Jena (Germany). Also a hearty appreciation to my family.

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