不同粒径微塑料对剑尾鱼肠道消化、抗氧化及免疫酶活性影响

Effects of Microplastics with Different Particle Sizes on Intestinal Digestion,Antioxidation and Immune Enzyme Activity of Swordtail Fish

研究表明,微塑料对生物体具有不利影响。本研究以剑尾鱼Xiphophorus helleri为实验对象,将其暴露于不同粒径(0、1μm、5μm、1μm与5μm按颗粒数1∶1混合粒径)、不同浓度(0、1×10^(6)粒/L、1×10^(7)粒/L)聚苯乙烯微塑料水环境72 h后,测定其消化酶、抗氧化酶及免疫酶活性。与对照组相比,各暴露组肠道淀粉酶、脂肪酶和胰蛋白酶活性均显著升高(P<0.05),超氧化物歧化酶和谷胱甘肽过氧化物酶活性显著下降(P<0.05),过氧化氢酶活性显著升高(P<0.05),丙二醛和溶菌酶活性显著升高(P<0.05)。微塑料急性暴露会干扰剑尾鱼对食物的消化吸收,并影响其肠道抗氧化酶和免疫酶的活性。

Plastics are widely used in many fields because of their stable physical and chemical properties.However,the annually increased global application and output of plastics have already led to the continuous accumulation of microplastics in the whole ecosystem.A large number of studies have shown that microplastics have adverse effects on organisms.In this study,swordtail fish(Xiphophorus helleri)were exposed to polystyrene microplastics at different particle sizes(0,1μm,5μm,and 1∶1 mixture of them)and different concentrations(0,1×10^(6) particles·L^(-1),and 1×10^(7) particles·L^(-1))in water environment for 72 h.The activities of digestive enzymes,antioxidant enzymes and immune enzymes were then determined.The results showed that compared with the control group,the activities of intestinal amylase,lipase and trypsin in all exposed groups were significantly increased(P<0.05).The activities of superoxide dismutase and glutathione peroxidase decreased significantly(P<0.05),while the activity of catalase increased significantly(P<0.05).Moreover,the activities of malondialdehyde and lysozyme also increased significantly(P<0.05).This study suggests that acute exposure to microplastics will interfere with food digestion and absorption of swordtail fish,and affect the activities of intestinal antioxidant enzymes and immune enzymes.