A Microencapsulation Method for Delivering Tetrodotoxin to Bivalves to Investigate Uptake and Accumulation |
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| Authors: | Laura Biessy Kirsty F. Smith Susanna A. Wood Annabel Tidy Roel van Ginkel Joel R. D. Bowater Ian Hawes |
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| Affiliation: | 1.Cawthron Institute, Coastal and Freshwater, Nelson 7010, New Zealand; (K.F.S.); (S.A.W.); (R.v.G.); (J.R.D.B.);2.Department of Biological Sciences, University of Waikato, Hamilton 3216, New Zealand;3.New Zealand Food Safety Science & Research Centre, Palmerston North 4442, New Zealand;4.School of Geography, Earth and Environmental Sciences, University of Birmingham, Birmingham B15 2TT, UK; |
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| Abstract: | Most marine biotoxins are produced by microalgae. The neurotoxin tetrodotoxin (TTX) has been reported in many seafood species worldwide but its source is unknown, making accumulation and depuration studies in shellfish difficult. Tetrodotoxin is a water-soluble toxin and cannot be directly ingested by shellfish. In the present study, a method was developed which involved binding TTX to solid particles of humic acid and encapsulating them in agar-gelatin capsules. A controlled quantity of TTX-containing microcapsules (size range 20–280 μm) was fed to Paphies australis, a bivalve known to accumulate TTX in the wild. The TTX-containing microcapsules were fed to P. australis every second day for 13 days. Ten P. australis (including five controls fed non-toxic microalgae) were harvested after 7 days and ten after 13 days. Paphies australis accumulated TTX, reaching concentrations of up to 103 µg kg−1 by day 13, exceeding the European Food Safety Authority recommended concentration of 44 μg kg−1 in shellfish. This novel method will allow future studies to explore the effects, accumulation and depuration rates of TTX in different animals and document how it is transferred through food webs. |
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| Keywords: | bioaccumulation feeding experiment humic acid marine toxin shellfish |
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