Microplastics are emergent contaminants threatening aquatic organisms including aquacultured fish. This study investigated the effects of high-density polyethylene (HDPE, 100 to 125 μm) on yellow perch (Perca flavescens) based on integrative evaluation including growth performance, nutritional status, nutrient metabolism, fish health, and gut microbial community. Five test diets (0, 1, 2, 4, or 8 g HDPE/100 g diet) containing 41% protein and 10.5% lipid were fed to juvenile perch (average body weight, 25.9 ± 0.2 g; n = 15) at a feeding rate of 1.5% to 2.0% body weight daily. The feeding trial was conducted in a flow-through water system for 9 wk with 3 tanks per treatment and 15 yellow perch per tank. No mortality or HDPE accumulation in the fish was found in any treatments. Weight gain and condition factor of fish were not significantly impacted by HDPE (P > 0.05). Compared to the control group, fish fed the 8% HDPE diet had significantly decreased levels of protein and ash (P < 0.05). In response to the increasing levels of HDPE exposure, the hepatosomatic index value, hepatocyte size, and liver glycogen level were increased, but lipid content was reduced in the liver tissues. Compared to the control treatment, fish fed the 8% HDPE diet had significant accumulations of total bile acids and different metabolism pathways such as bile acid biosynthesis, pyruvate metabolism, and carnitine synthesis. Significant enterocyte necrosis was documented in the foregut of fish fed the 2% or 8% HDPE diet; and significant cell sloughing was observed in the midgut and hindgut of fish fed the 8% HDPE diet. Fish fed the 2% HDPE diet harbored different microbiota communities compared to the control fish. This study demonstrates that HDPE ranging from 100 to 125 μm in feed can be evacuated by yellow perch with no impact on growth. However, dietary exposure to HDPE decreased whole fish nutrition quality, altered nutrient metabolism and the intestinal histopathology as well as microbiota community of yellow perch. The results indicate that extended exposure may pose a risk to fish health and jeopardize the nutrition quality of aquacultured end product. This hypothesis remains to be investigated further.

微塑料是威胁水生生物（包括水产养殖鱼类）的新兴污染物。本研究基于包括生长性能、营养状况、营养代谢、鱼类健康和肠道微生物群落在内的综合评价，调查了高密度聚乙烯（HDPE，100 至 125 μm）对黄鲈（Perca flavescens ）的影响。将含有 41% 蛋白质和 10.5% 脂质的五种试验日粮（0、1、2、4 或 8 g HDPE/100 g 日粮）喂给幼鲈鱼（平均体重，25.9 ± 0.2 g；n = 15) 以每天 1.5% 至 2.0% 体重的喂食率。饲养试验在流水系统中进行，为期 9 周，每次处理 3 个水箱，每个水箱 15 条黄鲈鱼。在任何处理中均未发现鱼死亡或 HDPE 积累。HDPE对鱼体增重和体况因子的影响不显着（P  > 0.05）。与对照组相比，喂食 8% HDPE 饲料的鱼的蛋白质和灰分水平显着降低（P < 0.05)。随着 HDPE 暴露水平的增加，肝体指数值、肝细胞大小和肝糖原水平增加，但肝组织中的脂质含量降低。与对照处理相比，饲喂 8% HDPE 饲料的鱼具有显着的总胆汁酸积累和不同的代谢途径，如胆汁酸生物合成、丙酮酸代谢和肉碱合成。在喂食 2% 或 8% HDPE 饲料的鱼的前肠中记录到明显的肠细胞坏死；在喂食 8% HDPE 日粮的鱼的中肠和后肠中观察到明显的细胞脱落。与对照鱼相比，喂食 2% HDPE 饮食的鱼拥有不同的微生物群落。该研究表明，饲料中 100 至 125 μm 的 HDPE 可以被黄鲈排出，而不影响生长。然而，高密度聚乙烯的膳食暴露降低了整鱼的营养质量，改变了营养代谢和肠道组织病理学以及黄鲈的微生物群落。结果表明，长时间接触可能对鱼类健康构成风险并危及水产养殖最终产品的营养质量。这个假设还有待进一步研究。