Toxicological consequences of polystyrene microplastics on Cirrhinus mrigala: effects on growth, body composition, nutrient digestibility, haematology and histopathology

Context Microplastics (MPs), whether originating from primary or secondary means, have emerged as a significant global issue nowadays. Aims The current research was designed to assess the toxicological consequences of polystyrene MPs (PS-MPs) on the growth, digestibility, body composition, haematology and histopathology of Cirrhinus mrigala fingerlings. Methods In this study, six test diets with different MP concentrations were used, including a control group (0% MPs) and groups with 0.5, 1, 1.5, 2 and 2.5% MPs in sunflower meal-based diets. For a 90-day duration, 270 fingerlings (6.54 ± 0.02 g fish−1) were placed in triplicate groups in tanks, with each tank consisting of 15 fingerlings, feeding at a rate equivalent to 5% of their live wet bodyweight. Key results The findings revealed a negative correlation between MP concentration and fingerlings performance, encompassing growth, digestibility, body composition, histopathology and hematology. Conclusions The results indicate that 2.5% MPs inclusion in C. mrigala adversely affects growth, digestibility, body composition, histopathology and hematology. Implications This research highlights the harmful effects of PS-MPs on C. mrigala fingerlings, emphasising urgent global action to address and mitigate aquatic ecosystem threats.