Experimental evidence of dietary ciguatoxin accumulation in an herbivorous coral reef fish
|Author(s)||Clausing Rachel J.1, Losen Barbara1, Oberhaensli Francois R.1, Darius H. Taiana2, Sibat Manoella3, Hess Philipp3, Swarzenski Peter W.1, Chinain Mireille2, Bottein Marie-Yasmine Dechraoui1|
|Affiliation(s)||1 : IAEA, IAEA Environm Labs, 4 Quai Antoine 1er, Monaco 98000, Monaco.
2 : Inst Louis Malarde UMR 241 EIO, Lab Microalgues Tox, BP 30, F-98713 Papeete Tahiti, French Polynesi, France.
3 : IFREMER, Lab Phycotoxines, Rue Ile Yeu, F-44311 Nantes, France.
|Source||Aquatic Toxicology (0166-445X) (Elsevier Science Bv), 2018-07 , Vol. 200 , P. 257-265|
|WOS© Times Cited||34|
|Keyword(s)||Ciguatoxin, Bioaccumulation, Growth dilution, Trophic transfer, Herbivorous fish, Experimental model|
Ciguatoxins (CTXs) are potent algal toxins that cause widespread ciguatera poisoning and are found ubiquitously in coral reef food webs. Here we developed an environmentally-relevant, experimental model of CTX trophic transfer involving dietary exposure of herbivorous fish to the CTX-producing microalgae Gambierdiscus polynesiensis. Juvenile Naso brevirostris were fed a gel-food embedded with microalgae for 16 weeks (89 cells g.1 fish daily, 0.4 ¦Ìg CTX3C equiv kg.1 fish). CTXs in muscle tissue were detectable after 2 weeks at levels above the threshold for human intoxication (1.2 ¡À 0.2 ¦Ìg CTX3C equiv kg.1). Although tissue CTX concentrations stabilized after 8 weeks (¡«3 ¡À 0.5 ¦Ìg CTX3C equiv kg.1), muscle toxin burden (total ¦Ìg CTX in muscle tissue) continued to increase linearly through the end of the experiment (16 weeks). Toxin accumulation was therefore continuous, yet masked by somatic growth dilution. The observed CTX concentrations, accumulation rates, and general absence of behavioural signs of intoxication are consistent with field observations and indicate that this method of dietary exposure may be used to develop predictive models of tissue-specific CTX uptake, metabolism and depuration. Results also imply that slow-growing fish may accumulate higher CTX flesh concentrations than fast-growing fish, which has important implications for global seafood safety.