Assessment of polystyrene microplastics as dietary additives in aquaculture species, Catla catla: Alters growth, feed utilization, nutritional composition, hematology and gut histopathology

Abstract

Recently, aquaculture species have been facing various negative consequences of ingesting microplastics (MPs). In order to find out the adverse impacts of MPs, this study aimed to assess growth, body composition, nutrient digestibility, hematological indices and gut histopathology of Catla catla fingerlings by the dietary exposure of polystyrene MPs (PS-MPs). C. catla (initial weight, 7.03±0.02 g; n, 270) were given PS-MPs at different inclusion concentrations i.e., 0 %, 0.5 %, 1 %, 1.5 %, 2 % and 2.5 % for 90 days. Fish were fed twice a day, about 5 % of their live weight. The water quality parameters such as temperature (25–27 °C), pH (7.3–8.3), dissolved oxygen (5.4–7.2 mg/L) were maintained at the regular basis throughout the experiment. PS-MPs significantly (p<0.05) inhibited growth and decreased nutritional digestibility of C. catla. Moreover, when compared to the control (without PS-MPs), fingerlings showed the lowest weight gain and the highest feed conversion ratio at 2.5 % PS-MPs concentration. PS-MPs at higher concentration significantly (p<0.05) lower the protein content and increase fat content of body, indicating less nutritional quality. Hematological indices were also affected significantly (p<0.05) by PS-MPs in a concentration dependent manner. According to a histopathological study of gut, 2.5 % PS-MPs concentration resulted in increased abnormalities and abrasions in the intestine. The findings of present study showed that PS-MPs had more prominent adverse impacts on growth, nutrient digestibility, body composition, hematology and gut histopathology of C. catla fingerlings at higher concentrations (2.5 %).

Keywords

• Body composition
• Catla catla
• Growth performance
• Gut histopathology
• Polystyrene microplastics