The evaluation of antioxidant system capacity is important in aquatic toxicology. It was aimed to characterize the liver antioxidant enzymes (SOD, CAT, GPX, GR, and GST) and to test the in vitro Zn effect (200 and 400 ZnSO₄ μg/L) in native fish Barbus meridionalis obtained from the Osor River (NE, Spain) influenced by Zn contamination. The maximal enzyme activities were at pH 7.0–7.5 and 100 mM phosphate buffer. Barbel showed high catalytic activity (high Vmax and low Km) indicating the efficient antioxidant detoxification ability. Direct Zn effect caused an antioxidant system imbalance. Mostly upon lower Zn concentration, GPX activity decreased (95–100 %) though CAT, GR, and GST increased (36–1543 %). GSH values either stimulated (290 %) or inhibited (85–93 %) due to tissue differences. The first record of barbel antioxidant enzyme characterization and in vitro data presenting an unbalanced antioxidant pattern could be significant to evaluate the metal pollution in the Osor River for further in vivo studies.

抗氧化剂系统容量的评估在水生毒理学中很重要。它旨在表征肝抗氧化酶（SOD，CAT，GPX，GR和GST），并测试在体外的Zn的效果（200和400的ZnSO ₄微克/升）的天然鱼鲤鲇从Osor的河得到（受西班牙锌污染的影响。最大的酶活性在pH 7.0-7.5和100 mM磷酸盐缓冲液下。Barbel显示出高催化活性（高Vmax和低Km）表明有效的抗氧化剂排毒能力。锌的直接作用导致抗氧化剂系统失衡。多数情况下，锌浓度较低时，尽管CAT，GR和GST升高（36–1543％），但GPX活性下降（95-100％）。由于组织差异，GSH值被刺激（290％）或被抑制（85–93％）。Barbel抗氧化酶表征的第一笔记录以及呈现不平衡抗氧化模式的体外数据对于评估Osor河中的金属污染以进行进一步的体内研究可能具有重要意义。