Microplastics accumulation in gut and revealing their impacts on nutritional quality and health of freshwater carp, Catla catla

The widespread presence of microplastics (MPs) in aquatic ecosystems raises concerns about their potential harm to aquatic life, particularly fish, which are a vital source of protein for human consumption. It emphasizes the importance of examining their occurrence and impacts. The focus of this study was to find out deleterious effects of polylactic acid MPs (PLA-MPs) on the Catla catla fingerlings by observing their growth, body composition, digestibility, histopathology, blood health, and mineral analysis. Utilizing sunflower meal (SFM) as the basal diet, six test diets were formulated, incorporating distinct MP concentrations: control (no MPs), 0.5 %, 1 %, 1.5 %, 2 %, and 2.5 %. These test diets were tested in three replicates of 15 fingerlings per tank and fed at 5 % equivalent of their live wet body weight for 90 days. After exposure to 2.5 % MPs, C. catla, fingerlings showed a significant decline in growth rate and feed utilization. Increased FCR and decreased WG (g) were observed in 2.5 % PLA-MPs. As MP levels increased, nutrient digestibility and minerals content decreased. PLA-MPs increased body fat and moisture, but decreased protein and ash content. MP exposure leads to significant changes in hematological parameters, including decreased RBCs, Hb, PLT, PCV, and MCHC, and increased WBCs, MCH, and MCV. Furthermore, histopathological examination of the gut showed increased intestinal abnormalities at the 2.5 % PLA-MPs concentration. This study underscored the adverse effects of PLA-MP pollution on the overall health performance of C. catla fingerlings. • Polylactic microplastics (PLA-MPs) are accumulated in the bodies of Catla catla after 90 days of dietary exposure. • Exposure to PLA-MPs significantly altered the growth and digestibility of C. catla . • The hematological parameters, intestinal histology and mineral composition also undergoe a major decrease in C. catla .