Studies that aim to characterise the susceptibility of the ecologically relevant and non-model fish polar cod (Boreogadus saida) to model carcinogens are required. Polar cod were exposed under laboratory conditions for six months to control, 0.03 μg BaP/g fish/week and 0.3 μg BaP/g fish/week dietary benzo(a)pyrene (BaP), a reference carcinogen. The concentrations of the 3-OH-BaP bile metabolite and transcriptional responses of genes involved in DNA adduct recognition (xpc), helicase activity (xpd), DNA repair (xpf, rad51) and tumour suppression (tp53) were assessed after 0, 1, 3 and 6 months of exposure, alongside body condition indexes (gonadosomatic index, hepatosomatic index and condition factor). Micronuclei and nuclear abnormalities in blood and spleen, and liver histopathological endpoints were assessed at the end of the experiment.

Fish grew steadily over the whole experiment and no mortality was recorded. The concentrations of 3-OH-BaP increased significantly after 1 month of exposure to the highest BaP concentration and after 6 months of exposure to all BaP concentrations showing the biotransformation of the mother compound. Nevertheless, no significant induction of gene transcripts involved in DNA damage repair or tumour suppression were observed at the selected sampling times. These results together with the absence of chromosomal damage in blood and spleen cells, the subtle increase in nuclear abnormalities observed in spleen cells and the low occurrence of foci of cellular alteration suggested that the exposure was below the threshold of observable effects. Taken together, the results showed that polar cod was not susceptible to carcinogenesis using the BaP exposure regime employed herein.

需要进行旨在表征生态相关和非模型鱼类极地鳕鱼 ( Boreogadus Saida ) 对模型致癌物的敏感性的研究。极地鳕鱼在实验室条件下暴露六个月，以控制 0.03 μg BaP/g 鱼/周和 0.3 μg BaP/g 鱼/周膳食苯并 (a) 芘 (BaP)，一种参考致癌物。3-OH-BaP 胆汁代谢物的浓度和参与 DNA 加合物识别 ( xpc )、解旋酶活性 ( xpd )、DNA 修复 ( xpf、rad51 ) 和肿瘤抑制 ( tp53 )的基因的转录反应) 在暴露 0、1、3 和 6 个月后与身体状况指数（性腺体指数、肝体指数和状况因子）一起进行评估。在实验结束时评估血液和脾脏中的微核和核异常以及肝脏组织病理学终点。

鱼在整个实验中稳定生长，没有记录到死亡。3-OH-BaP 的浓度在暴露于最高 BaP 浓度 1 个月后和暴露于所有 BaP 浓度 6 个月后显着增加，显示母体化合物的生物转化。然而，在选定的采样时间没有观察到参与 DNA 损伤修复或肿瘤抑制的基因转录的显着诱导。这些结果连同血液和脾细胞中没有染色体损伤、在脾细胞中观察到的核异常的细微增加以及细胞改变病灶的发生率低，表明暴露低于可观察到的影响阈值。综合起来，