Wei Lu, Li Yu, Ye Hengzhen, Xiao Juan, Hogstrand Christer, Green Iain, Guo Zhiqiang, Han Dong
State Key Laboratory of Marine Resource Utilization in South China Sea, School of Life and Pharmaceutical Sciences, College of Food Science and Engineering, Hainan University, Haikou, China.
Metals Metabolism Group, School of Life Course Sciences, King's College London, London, United Kingdom.
Front Physiol. 2021 Feb 25;12:640898. doi: 10.3389/fphys.2021.640898. eCollection 2021.
Diet quality greatly affects an animal's performance and metabolism. Despite the fact that trivalent chromium [Cr(III)] is considered an essential element and is widely used in nutritional supplements for animals and humans, the potential toxicity of Cr(III) is unclear. Here, liver transcriptome sequencing was performed on coral trout () exposed to 200 mg kg of dietary organic Cr(III) [as chromium picolinate (CrPic)] for 8 weeks. One-hundred-and thirteen differentially expressed genes (DEGs) were identified in response to Cr(III) stress, in comparison to the control, including 31 up-regulated and 82 down-regulated DEGs. Clusters of Orthologous Groups of proteins (COG) classifies DEGs into 15 functional categories, with the predominant category being related to lipid transport and metabolism (9.73%). The Kyoto Encyclopedia of Genes and Genomes (KEGG) assigned DEGs to six major categories with robust DEGs as part of the lipid metabolism pathway (18.58%). Moreover, KEGG functional enrichment analysis showed that these DEGs are primarily related to steroid biosynthesis, terpenoid backbone biosynthesis, and steroid hormone biosynthesis pathways, of which steroid biosynthesis was the most significant pathway, and 12 key up-regulated DEGs (, , and ) were found for steroid biosynthesis pathways. To validate the RNA sequencing data using quantitative real-time PCR (qRT-PCR), qRT-PCR results indicate that the expression of genes encoding HMGCR, TM7SF2, TRYP2, CTRL, EBP, LSS, and CYP51 were induced, while those encoding THRSP, LCE, and MCM5 were reduced, consistent with RNA-seq results. This findings provides the first evidence that a long-term high dose of Cr(III) intake causes lipid metabolism disorder and potential toxicity in fish. Cautious health risk assessment of dietary Cr(III) intake is therefore highly recommended for the commercial and/or natural diets of aquatic animals, which has previously largely been ignored.
饮食质量对动物的生长性能和新陈代谢有很大影响。尽管三价铬[Cr(III)]被认为是一种必需元素，并广泛用于动物和人类的营养补充剂中，但其潜在毒性尚不清楚。在此，对暴露于200 mg/kg膳食有机铬[Cr(III)，以吡啶甲酸铬（CrPic）形式]8周的尖吻鲈（）进行肝脏转录组测序。与对照组相比，在Cr(III)应激反应中鉴定出113个差异表达基因（DEG），包括31个上调和82个下调的DEG。蛋白质直系同源簇（COG）将DEG分为15个功能类别，主要类别与脂质转运和代谢相关（9.73%）。京都基因与基因组百科全书（KEGG）将DEG分配到六个主要类别，其中强大的DEG作为脂质代谢途径的一部分（18.58%）。此外，KEGG功能富集分析表明，这些DEG主要与类固醇生物合成、萜类骨架生物合成和类固醇激素生物合成途径相关，其中类固醇生物合成是最显著的途径，并且在类固醇生物合成途径中发现了12个关键上调DEG（、和）。为了使用定量实时PCR（qRT-PCR）验证RNA测序数据，qRT-PCR结果表明，编码HMGCR、TM7SF2、TRYP2、CTRL、EBP、LSS和CYP51的基因表达被诱导，而编码THRSP、LCE和MCM5的基因表达则降低，这与RNA-seq结果一致。这一发现首次证明长期高剂量摄入Cr(III)会导致鱼类脂质代谢紊乱和潜在毒性。因此，强烈建议对水生动物的商业和/或天然饲料中膳食Cr(III)的摄入量进行谨慎的健康风险评估，而这一点此前在很大程度上被忽视了。
