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 μg CTX3C equiv kg⁻¹ fish). CTXs in muscle tissue were detectable after 2 weeks at levels above the threshold for human intoxication (1.2 ± 0.2 μg CTX3C equiv kg⁻¹). Although tissue CTX concentrations stabilized after 8 weeks (∼3 ± 0.5 μg CTX3C equiv kg⁻¹), muscle toxin burden (total μg 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.

Ciguatoxins（CTX）是有效的藻类毒素，可引起广泛的Ciguatera中毒，并在珊瑚礁食物网中普遍发现。在这里，我们开发了一种与环境相关的CTX营养转移实验模型，其中涉及将草食性鱼类的饮食与CTX产生的微藻Gambierdiscus polynesiensis进行饮食接触。向幼年Naso brevirostris喂食了嵌入微藻的凝胶食品，持续了16周（每天89条细胞g ^-1条鱼，0.4μgCTX3C当量kg ^-1条鱼）。2周后，在高于人体中毒阈值的水平（1.2±0.2μgCTX3C当量kg ^-1），可检测到肌肉组织中的CTX 。尽管组织CTX浓度在8周后稳定下来（〜3±0.5μgCTX3C等效千克^-1），直到实验结束（16周），肌肉毒素负担（肌肉组织中的总Cg微克CTX）持续线性增加。因此毒素积累是连续的，但被体细胞生长稀释所掩盖。观察到的CTX浓度，蓄积率和一般没有中毒的行为迹象与现场观察一致，表明这种饮食接触方法可用于建立组织特异性CTX摄取，代谢和净化的预测模型。结果还暗示，与快速生长的鱼类相比，生长缓慢的鱼类积累的CTX肉浓度更高，这对全球海鲜安全性具有重要意义。