Effects of Polystyrene Nanoplastics on Oxidative Stress, Blood Biochemistry, and Digestive Enzyme Activity in Goldfish (Carassius auratus)

Plastic pollution in aquatic ecosystems has become a global concern, and nanoplastics, due to their small size and high penetration potential, pose significant risks to aquatic organisms. This study aimed to evaluate the effects of polystyrene nanoplastics (PS-NPs) on oxidative stress biomarkers, blood biochemical parameters, and digestive enzyme activities in Goldfish (<i>Carassius auratus</i>). The experiment was conducted over 21 days, exposing fish to four different dietary concentrations of PS-NPs (0, 1, 10, and 100 mg/Kg). The results showed that chronic exposure to 50 nm PS-NPs significantly increased the activity of antioxidant enzymes (CAT, SOD, and GPx) and MDA activity in the gill, kidney, and liver tissues, indicating the induction of oxidative stress. Furthermore, notable alterations were observed in blood biochemical enzymes (alkaline phosphatase [ALP], alanine aminotransferase [ALT], aspartate aminotransferase [AST], and lactate dehydrogenase [LDH]), suggesting cellular damage and physiological disturbances. Additionally, PS-NP exposure affected the activity of digestive enzymes (amylase, lipase, and protease), which may impact nutrient digestion and absorption. These findings highlight that PS-NPs can adversely affect aquatic animal health and may influence the nutritional quality of fish. Therefore, further research is necessary to assess the long-term ecological and toxicological impacts of nanoplastics in freshwater ecosystems.