Microplastic pollution has drawn the attention of both scientists and the public regarding their potential ecotoxicological risks. In the present study, we carried out aqueous exposure experiments to adult zebrafish with polystyrene microplastics (5 μm) at a wide range of concentrations (0.001-20 mg/L, equals to 14.5∼2.9 × 10⁵ particles/mL). Our results showed the gastrointestinal tract (GIT) was the dominant microplastic accumulation site in zebrafish, followed by the gill, whereas no microplastics were detected in the brain or muscle. Microplastic accumulation in GIT did not cause obvious damages to intestinal villi in general. However, the thickness of muscularis layer in the foregut reduced by 32% after 1 mg/L (1.45 × 10⁴ particles/mL) microplastic exposure. As there were no signs of oxidative stress or other histological changes found in the fish, we further investigated the energy-supplying influential factors. We found that the zebrafish became hyperactive after microplastic exposure, whose swimming distance had increased to 1.3-2.4 folds than that of control, and also stayed at manic and active states much longer. The fish behavioural alteration is probably attributed to the particulate matter stimulation and the up-regulation of estrogen contents. Results also showed that the excessive movements of zebrafish also led to decreased glucose and acetaldehyde metabolite contents and increased amino acid amounts, which further proved the shortage of energy-supplying substances. Therefore, the present study suggests that micro-sized microplastics can induce obvious behavioural abnormality at concentrations that some other toxicological endpoints may not warn effects.

微塑料污染已经引起了科学家和公众的潜在生态毒理学风险。在本研究中，我们对浓度范围广泛（0.001-20 mg / L，等于14.5〜2.9×10 ⁵颗粒/ mL）的聚苯乙烯微塑料（5μm）对成年斑马鱼进行了水暴露实验。我们的研究结果表明，胃肠道（GIT）是斑马鱼中占主导地位的微塑性蓄积位点，其次是the，而在大脑或肌肉中未检测到微塑性。一般而言，GIT中的微塑料积聚不会对肠绒毛造成明显损害。然而，在1 mg / L后，前肠中的肌层厚度减少了32％（1.45×10 ⁴颗粒/ mL）的微塑料暴露。由于在鱼类中没有发现氧化应激或其他组织学变化的迹象，因此我们进一步研究了能量供应的影响因素。我们发现斑马鱼暴露于微塑料后变得活跃，其游泳距离比对照的游泳距离增加了1.3-2.4倍，并且在躁狂和活跃状态的停留时间更长。鱼的行为改变可能归因于颗粒物刺激和雌激素含量的上调。结果还表明，斑马鱼的过度运动还导致葡萄糖和乙醛代谢产物含量降低，氨基酸含量增加，进一步证明了能量供应物质的短缺。因此，