The amount of Sargassum spp. arriving in the Caribbean Sea has increased steadily in the last few years, producing a profound environmental impact on the ecological dynamics of the coasts of the Yucatan Peninsula. We characterized the toxicological effects of an ethanolic extract of Sargassum spp. on zebrafish (Danio rerio) embryos (ZFEs) in a 96‐h static bioassay using T1 (0.01 mg/L), T2 (0.1 mg/L), T3 (1 mg/L), T4 (10 mg/L), T5 (25 mg/L), T6 (50 mg/L), T7 (75 mg/L), T8 (100 mg/L), T9 (200 mg/L), and T10 (400 mg/L). In this extract, we detected 74 compounds by gas chromatography‐mass spectrometry (GC‐MS), of which hexadecanoic acid methyl ester, and 2‐pentanone 4‐hydroxy‐4‐methyl, were the most abundant. In ZFEs, a median lethal concentration of 251 mg/L was estimated. Exposed embryos exhibited extensive morphological changes, including edema in the yolk sac, scoliosis, and loss of pigmentation, as well as malformations of the head, tail, and eyes. By integrating these abnormalities using the Integrated Biological Response (IBRv2) and General Morphological Score (GMS) indices, we were able to determine that ZFEs exposed to 200 mg/L (T9) exhibited the most pronounced biological response in comparison with the other groups. In the comparative transcriptomic analysis, 66 genes were upregulated, and 246 genes were downregulated in the group exposed to 200 mg/L compared with the control group. In the upregulated genes, we identified several gene ontology‐enriched terms, such as response to xenobiotic stimuli, cellular response to chemical stimulus, transcriptional regulation, pigment metabolic process, erythrocyte differentiation and embryonic hemopoiesis, extracellular matrix organization, and chondrocyte differentiation involved in endochondral bone morphogenesis, among others. In the down‐regulated genes, we found many genes associated with nervous system processes, sensory and visual perception, response to abiotic stimulus, and the nucleoside phosphate biosynthetic process. The probable connections among the morphological changes observed in the transcriptome are thoroughly discussed. Our findings suggest that Sargassum spp. exposure can induce a wide negative impact on zebrafish embryos. Environ Toxicol Chem 2024;00:1–15. © 2024 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

中文翻译：

---

马尾藻属 乙醇提取物引起斑马鱼（Danio rerio）胚胎的毒性反应和畸形

大量的马尾藻属种。过去几年中，抵达加勒比海的海洋生物数量稳步增加，对尤卡坦半岛海岸的生态动态产生了深远的环境影响。我们表征了乙醇提取物的毒理学作用马尾藻属种。在斑马鱼上（斑马鱼）使用 T1 (0.01 mg/L)、T2 (0.1 mg/L)、T3 (1 mg/L)、T4 (10 mg/L)、T5 (25 mg/L) 进行 96 小时静态生物测定中的胚胎 (ZFE) ）、T6（50 毫克/升）、T7（75 毫克/升）、T8（100 毫克/升）、T9（200 毫克/升）和 T10（400 毫克/升）。在该提取物中，我们通过气相色谱-质谱法 (GC-MS) 检测到 74 种化合物，其中十六烷酸甲酯和 2-戊酮 4-羟基-4-甲基含量最丰富。在 ZFE 中，估计中位致死浓度为 251 mg/L。暴露的胚胎表现出广泛的形态变化，包括卵黄囊水肿、脊柱侧弯、色素沉着丧失，以及头部、尾部和眼睛的畸形。通过使用综合生物反应 (IBRv2) 和一般形态评分 (GMS) 指数整合这些异常，我们能够确定暴露于 200 mg/L (T9) 的 ZFE 与其他组相比表现出最明显的生物反应。在比较转录组分析中，与对照组相比，200 mg/L暴露组有66个基因上调，246个基因下调。在上调基因中，我们确定了几个基因本体丰富的术语，例如对外源刺激的反应、对化学刺激的细胞反应、转录调节、色素代谢过程、红细胞分化和胚胎造血、细胞外基质组织以及软骨内参与的软骨细胞分化。骨形态发生等。在下调的基因中，我们发现许多与神经系统过程、感觉和视觉感知、对非生物刺激的反应以及核苷磷酸生物合成过程相关的基因。彻底讨论了转录组中观察到的形态变化之间可能的联系。我们的研究结果表明马尾藻属种。暴露会对斑马鱼胚胎产生广泛的负面影响。环境毒理化学2024；00：1–15。© 2024 作者。环境毒理学和化学由 Wiley periodicals LLC 代表 SETAC 出版。