Modélisation de la détoxication de mollusques bivalves contenant des phycotoxines paralysantes ou diarrhéiques

• Main Author: Gueguen, Marielle
• Format: Doctoral or Postdoctoral Thesis
• Language: French; English
• Published: Université de Nantes 2009
• Subjects: Modélisation; Mytilus edulis; Crassostrea gigas; phycotoxines; détoxication; acide okadaïque; toxines paralysantes; Modelling; phycotoxins; detoxification; okadaix acid; paralytic toxin; Pacific
• Online Access: https://archimer.ifremer.fr/doc/00003/11473/8032.pdf; https://archimer.ifremer.fr/doc/00003/11473/

The purpose of this study is to implement models to describe detoxification kinetics of Pacific oysters Crassostrea gigas and Blue mussels Mytilus edulis containing paralytic and diarrheic phycotoxins respectively. First, experimental trials made it possible to complement data from the literature regarding the understanding of processes involved in mollusc detoxification. In particular, they pointed out a difference in the mollusc capacity to degrade cellwalls of phycotoxin-producing dinoflagellates, according to their en cystement capacities. It was observed that paralytic phycotoxins reached the various oyster tissues whereas diarrheic toxins were mainly sequestred in the digestive gland of mussels. The latter seem to be retained by lysosomes localized in digestive cells. The influence of intrinsic and extrinsic variables was also demonstrated. Then, the results obtained made it possible to implement various models taking into account transfers between tissues, biotransformations and the influence of environmental variables. It was proved that the detoxification kinetics of oysters containing paralytic toxins can be represented by two-compartment model, representing the digestive gland and the other tissues, the detoxification coefficients depending on environmental variables and on ratios between the various saxitoxin analogues. The detoxification of mussels containing diarrheic toxins can be simulated by a one-compartment model where the detoxification coefficient depends on environmental variables. Cette étude a pour objectif la mise en place de modèles permettant de décrire la cinétique de détoxication des huîtres Crassostrea gigas et des moules Mytilus edulis contenant des phycotoxines de type paralysant et diarrhéique respectivement. Dans un premier temps, des études ont permis de compléter les connaissances de la littérature sur la compréhension des processus entrant en jeu lors de la détoxication des mollusques. Il a ainsi été mis en évidence une différence dans la capacité des mollusques à dégrader ...