Spills of diluted bitumen (dilbit) from pipelines pose a risk to the health of aquatic organisms, including fish, and with expected increases in production and transportation of dilbit, these risks could increase. To date, the majority of studies have investigated effects of fresh dilbit on aquatic organisms, but little is known about effects of weathered sediment-bound dilbit, including mechanisms of toxicity. The goal of this study was to use ¹H NMR based metabolomics to identify altered metabolites and pathways in early life-stages of zebrafish (Danio rerio) exposed to a sediment derived water-soluble fraction of dilbit (SDWSF) to better understand mechanisms of adverse effects. Zebrafish embryos exposed to the SDWSF until 120 hours post-fertilization exhibited increased prevalence of pericardial edema, yolk sac edema, and swim bladder malformations that are typical of exposure to fresh dilbit. Concentrations of nine metabolites (alanine, glutamine, lysine, threonine, tyrosine, betaine, taurine, inosine, and glycerol) were altered in embryos exposed to SDWSF. Pathway topology analysis revealed four potentially impacted pathways: 1) phenylalanine, tyrosine, and tryptophan biosynthesis, 2) taurine and hypotaurine metabolism, 3) alanine, aspartate, and glutamate metabolism, and 4) glycine, serine, and threonine metabolism. Altered metabolites were linked to several biological process, that when perturbed could be key events in mechanisms of developmental effects observed in embryos. Future studies should further investigate the role of perturbations to these metabolites and pathways to determine the specific role they might play in adverse effects of exposure to dilbit.

管道中稀释沥青（dilbit）的泄漏对包括鱼类在内的水生生物的健康构成风险，并且随着稀释沥青生产和运输的预期增加，这些风险可能会增加。迄今为止，大多数研究都调查了新鲜稀释沥青对水生生物的影响，但对风化沉积物结合稀释沥青的影响（包括毒性机制）知之甚少。本研究的目的是使用基于¹ H NMR 的代谢组学来识别斑马鱼 (Danio rerio) 暴露于沉积物衍生的水溶性 Dilbit (SDWSF) 的早期生命阶段的代谢物和途径的改变，以更好地了解不利机制影响。暴露于 SDWSF 直至受精后 120 小时的斑马鱼胚胎表现出心包水肿、卵黄囊水肿和鱼鳔畸形的患病率增加，这些是暴露于新鲜稀释液的典型特征。暴露于 SDWSF 的胚胎中九种代谢物（丙氨酸、谷氨酰胺、赖氨酸、苏氨酸、酪氨酸、甜菜碱、牛磺酸、肌苷和甘油）的浓度发生了变化。通路拓扑分析揭示了四种可能受影响的通路：1) 苯丙氨酸、酪氨酸和色氨酸生物合成，2) 牛磺酸和亚牛磺酸代谢，3) 丙氨酸、天冬氨酸和谷氨酸代谢，以及 4) 甘氨酸、丝氨酸和苏氨酸代谢。改变的代谢物与多种生物过程有关，当这些生物过程受到干扰时，可能是胚胎中观察到的发育效应机制中的关键事件。未来的研究应进一步研究扰动对这些代谢物和途径的作用，以确定它们在接触迪尔比特的不利影响中可能发挥的具体作用。