Chronic exposure to high-density polyethylene microplastic through feeding alters the nutrient metabolism of juvenile yellow perch (Perca flavescens)

Authors: LU, XING - CHINESE ACADEMY OF SCIENCES; DENG, DONG-FANG - UNIVERSITY OF WISCONSIN; HUANG, FEI - UNIVERSITY OF WISCONSIN; CASU, FABIO - SOUTH CAROLINA DEPARTMENT OF NATURAL RESOURCES; KRACO, EMMA; NEWTON, RYAN - UNIVERSITY OF WISCONSIN; ZOHN, MERRY - OAK RIDGE INSTITUTE FOR SCIENCE AND EDUCATION (ORISE); TEH, SWEE - UNIVERSITY OF CALIFORNIA, DAVIS; WATSON, AARON - UNIVERSITY OF CALIFORNIA, DAVIS; SHEPHERD, BRIAN; MA, YING - UNIVERSITY OF WISCONSIN; DAWOOD, MAHMOUND - KAFRELSHEIKH UNIVERSITY; MENDOZA, LORENA - UNIVERSITY OF WISCONSIN

Submitted to: Animal Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/5/2022
Publication Date: 2/5/2022
Citation: Lu, X., Deng, D., Huang, F., Casu, F., Kraco, E.K., Newton, R., Zohn, M., Teh, S.J., Watson, A.M., Shepherd, B.S., Ma, Y., Dawood, M.A., Mendoza, L.R. 2022. Chronic exposure to high-density polyethylene microplastic through feeding alters the nutrient metabolism of juvenile yellow perch (Perca flavescens). Animal Nutrition. 9:143-158j. https://doi.org/10.1016/j.aninu.2022.01.007.
DOI: https://doi.org/10.1016/j.aninu.2022.01.007

Interpretive Summary: Microplastics are pervasive (less than 5 mm in size) plastic contaminants that have been shown to threaten aquatic organisms, but the potential impact on aquacultured fish exposed to microplastics is poorly understood. This study examined the effects of dietary high-density polyethelene (HDPE) plastic particles on growth and physiology in juvenile yellow perch (Perca flavescens). At the end of the nine week feeding trial, no mortality or accumulation of HDPE was found in any fish from control or HDPE-treated diets. However, fish fed the highest HDPE levels showed changes in whole-body composition, which was also associated with altered pathophysiology in the liver and intestines. As emergent aquatic contaminants, microplastics may pose physiological risks to aquaculture species.

Technical Abstract: Microplastics (MPs) are emergent contaminants that threaten aquatic organisms. While multiple studies have begun to investigate the effects of aquatic MP exposure in fish, little is known about the potential impact on aquacultured fish fed MPs-contaminated feed. This study aimed to understand the potential effects of dietary high density (HDPE, 100-125 µm) on juvenile yellow perch (Perca flavescens), an ecologically and economically important fish in the United State's Great Lakes region. Each of five test diets (0, 1, 2, 4, or 8 g HDPE/100 g diet) contained an equal level of protein, lipid, and carbohydrate and were fed to the fish (average body weight: 25.9 g) at a feeding rate of 1.5 to 2.0% body weight daily. The feeding trial was conducted in aflow-through water system with three tanks per treatment and 15 fish per tank. At the end of the nine-week feeding, no mortality or accumulation of HDPE was found in any treatment. Fish growth and condition factor were not significantly impacted by HDPE exposure (P > 0.05). Fish fed the 8% HDPE diet had significantly decreased protein and ash content compared to the fish fed the diet with no added HDPE (P < 0.05). The 8% HDPE diet led to increased liver weight, enlarged hepatocytes, decreased lipid, increased glycogen content, and accumulated bile acids in the liver. Compared to the control fish, higher scores of enterocyte necrosis were measured in the foregut of fish fed the 2% or 8% HDPE diet. Significant cell sloughing scores were observed in the midgut and hindgut of fish fed 8% HDPE. Fish fed the 2% HDPE diet harbored different microbiota communities compared to the control fish. This study demonstrates that HDPE taken from feeding were evacuated by yellow perch under the current exposure conditions. The 9-week exposure did not adversely influence the growth and survival of fish but significantly disrupted the intestinal microbiota community and liver functions, which may attribute the disturbance of nutrient metabolism and utilization in the perch. It is possible that an extended period of exposure could pose risks to fish health, which will require further investigation.