This study aims at the assessment of mercury (Hg)-selenium (Se) antagonism in fish. For this purpose, rainbow trout fish (Oncorhynchus mykiss) were exposed to methylmercury (MeHg) under controlled conditions, in the presence or absence of selenomethionine (SeMet) using an in-house prepared diet (enriched with MeHg and SeMet at 0.2 μg/g and 5.0 μg/g, respectively). The total duration of the exposure study was 3 months. Fish was sampled and analysed for total Se (Se_T) and total mercury (Hg_T) content after 1, 2 and 3 months of exposure. Six feeding protocols were compared, depending on the exposure type: (i) no MeHg nor SeMet exposure (control group); (ii) exposure to SeMet solely; (iii) exposure to MeHg solely; (iv) exposure to both MeHg and SeMet; (v) exposure first to MeHg during 1 month and then to SeMet during 2 months and (vi), exposure to SeMet during 1 month and then to MeHg for 2 months. The levels of Se_T and Hg_T in the fish (control and supplemented with MeHg/SeMet) were measured by inductively coupled plasma-mass spectrometry (ICPMS).

Steadily (linear) bioaccumulation of MeHg in the fish muscle occurred when the fish were exposed individually to this species during the period. The bioaccumulation of MeHg is diminished when the fish are firstly exposed to SeMet and then to MeHg, hence indicating the MeHg detoxification due to SeMet supplementation.

本研究旨在评估鱼类对汞 (Hg)-硒 (Se) 的拮抗作用。为此，虹鳟鱼 ( Oncorhynchus mykiss ) 在受控条件下暴露于甲基汞 (MeHg)，在存在或不存在硒代蛋氨酸 (SeMet) 的情况下，使用内部制备的饮食（富含 MeHg 和 SeMet，浓度为 0.2 μg/g和 5.0 μg/g）。暴露研究的总持续时间为 3 个月。在暴露 1、2 和 3 个月后，对鱼进行取样并分析其总硒 (Se _T ) 和总汞 (Hg _T ) 含量。根据暴露类型，比较了六种喂养方案：(i)无甲基汞或硒暴露（对照组）；(ii)仅暴露于 SeMet；(三)仅接触甲基汞；(iv)接触甲基汞和硒化氢；(v)先在 1 个月内接触 MeHg，然后在 2 个月内接触 SeMet，以及 (vi) 在 1 个月内接触 SeMet，然后在 MeHg 下接触 2 个月。通过电感耦合等离子体质谱法 (ICPMS) 测量鱼（对照和补充 MeHg/SeMet）中Se _T和 Hg _T的水平。

在此期间，当鱼单独接触该物种时，鱼肌肉中会发生甲基汞的稳定（线性）生物累积。当鱼先接触 SeMet 再接触 MeHg 时，MeHg 的生物积累减少，因此表明由于补充 SeMet 导致 MeHg 解毒。