Increasing global research has identified microplastics (MPs) to be impacting marine organisms. The present work aimed at investigating the physiological and behavioral effects of thirty-six juvenile Sparus aurata exposed to control, virgin and weathered MPs enriched diets during a 21-day period under controlled conditions. Physiological effects were assessed in liver and brain using the following biomarkers: activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and glutathione reductase (GRd), the detoxifying enzyme glutathione S-transferase (GST) and malondialdehyde (MDA) as indicative of lipid peroxidation. Individuals were recorded for behavior analysis (i.e. social interactions and feeding behavior). Results revealed an increase in cellular stress from control to weathered fish groups, with the virgin group showing intermediate levels in all quantified biomarkers. Significant differences were found in the liver for all biomarkers except for MDA, suggesting that exposure time to MPs in this experiment is long enough to trigger the activation of antioxidant enzymes but not to produce cell damage by lipid peroxidation. In brain tissue samples, fish from the weathered group presented significantly higher values for CAT and SOD, highlighting its function as primary antioxidants. Regarding behavioral effects, results showed that the two MPs enriched groups were significantly bolder during social interactions and, although no significantly, tended to be more active during feeding. In conclusion, MPs which have been weathered in marine environmental conditions produces a higher physiological response than virgin MPs but also, a physiological response is variable depending on the tissue analyzed. In addition, a short period to MP exposure seems to affect overall social and feeding behavior but, further research is needed to assess long-term effects of MP ingestion and its potential consequences on fish populations.

越来越多的全球研究已确定微塑料（MPs）正在影响海洋生物。目前的工作旨在调查36个少年Sparus aurata的生理和行为影响在受控条件下，在21天内暴露于对照，原始和风化的MP饮食中。使用以下生物标志物评估肝和脑的生理作用：抗氧化酶过氧化氢酶（CAT），超氧化物歧化酶（SOD），谷胱甘肽过氧化物酶（GPx）和谷胱甘肽还原酶（GRd）的活性，解毒酶谷胱甘肽S-转移酶（GST） ）和丙二醛（MDA）来指示脂质过氧化。记录个体以进行行为分析（即社交互动和进食行为）。结果表明，从对照组到风化鱼组的细胞应激增加，其中处女组在所有定量生物标志物中均处于中等水平。在肝脏中，除MDA以外的所有生物标志物均存在显着差异，提示该实验中MP的暴露时间足够长，可以触发抗氧化酶的激活，但不会因脂质过氧化而对细胞造成损害。在脑组织样品中，风化组的鱼的CAT和SOD值明显更高，突出了其作为主要抗氧化剂的功能。关于行为影响，结果表明，在社交互动中，两个富含MP的组显着更大胆，尽管进食期间却没有那么活跃，尽管趋于活跃。总之，与原始MP相比，在海洋环境条件下风化的MP产生更高的生理反应，但是生理反应根据所分析的组织而变化。此外，短暂的MP暴露似乎会影响整体的社交和进食行为，但是，