Ciguatoxins(CTX),由冈比亚和福约属的鞭毛藻产生的有效神经毒素,在通常食用的鱼类中积累,导致人类雪瓜中毒。太平洋礁鱼的野外收集显示,消耗的CTX经历氧化生物转化,导致了许多,经常中毒的类似物。根据我们的研究显示,食草鱼的肉中CTX快速积累,我们使用相同的实验室模型来检测PacificCTX在长期饮食暴露后的组织分布和代谢.Nasobrevirostris在16周内以0.36ngCTX3C当量g-1鱼d-1的恒定剂量率消耗了Gambierdiscuspolynesiensis的细胞。鱼组织的CTX毒性测定显示,暴露鱼的所有组织(8个组织加上尸体)中的CTX活性,在脾脏中浓度最高。肌肉组织保留了最大比例的CTX,占总组织负荷的44%。此外,相对于我们之前的研究,我们发现,生长速度较慢的大鱼在其肉中吸收了较高比例的摄入毒素(13%vs.2%)。肌肉提取物的分析显示存在CTX3C和CTX3B以及显示2,3-二羟基CTX3C的m/z转变的生物转化产物。这是模型消费者中藻类CTX氧化转化的第一个实验证据,并且已知CTX载体进入鱼食网。这些发现表明,供人类食用的肉携带大部分毒素,增长率可以影响暴露和积累之间的关系,对风险评估和制定旨在确保海鲜安全的监管措施具有重大影响。
Ciguatoxins (CTXs), potent neurotoxins produced by dinoflagellates of the genera Gambierdiscus and Fukuyoa, accumulate in commonly consumed fish species, causing human ciguatera poisoning. Field collections of Pacific reef fish reveal that consumed CTXs undergo oxidative biotransformations, resulting in numerous, often toxified analogs. Following our study showing rapid CTX accumulation in flesh of an herbivorous fish, we used the same laboratory model to examine the tissue distribution and metabolization of Pacific CTXs following long-term dietary exposure. Naso brevirostris consumed cells of Gambierdiscus polynesiensis in a gel food matrix over 16 weeks at a constant dose rate of 0.36 ng CTX3C equiv g-1 fish d-1. CTX toxicity determination of fish tissues showed CTX activity in all tissues of exposed fish (eight tissues plus the carcass), with the highest concentrations in the spleen. Muscle tissue retained the largest proportion of CTXs, with 44% of the total tissue burden. Moreover, relative to our previous study, we found that larger fish with slower growth rates assimilated a higher proportion of ingested toxin in their flesh (13% vs. 2%). Analysis of muscle extracts revealed the presence of CTX3C and CTX3B as well as a biotransformed product showing the m/z transitions of 2,3-dihydroxyCTX3C. This is the first experimental evidence of oxidative transformation of an algal CTX in a model consumer and known vector of CTX into the fish food web. These findings that the flesh intended for human consumption carries the majority of the toxin load, and that growth rates can influence the relationship between exposure and accumulation, have significant implications in risk assessment and the development of regulatory measures aimed at ensuring seafood safety.