Effects of Virgin Microplastics on Growth, Intestinal Morphology and Microbiota on Largemouth Bass (Micropterus salmoides)

Microplastics (MPs), classified as plastic debris less than 5 mm in size, are widely found in various aquatic environments. However, there have been few studies regarding their potential threat under aquaculture conditions. The aim of this study was to investigate the general health, intestinal morphology and microbiota of virgin polypropylene MPs (3–4 mm) on largemouth bass (Micropterus salmoides) over a 28-d exposure period. Four groups were divided according to whether the MPs were added in water or in food. The results disproved the hypothesis that MPs expose may adversely affect the growth of fish. Largemouth bass expelled MPs with minimal harm to the organism. MPs exposure had no significant effect on the community composition or diversity of intestinal microbial, although it could partly influence intestinal morphology, and the recombination process of the intestinal microbial community. Fish may be more sensitive to answer MPs exposure in water than in feed. Proteobacteria could potentially be pathogenic bacteria phylum in fish gut when affected by MPs. This research represents an innovative attempt to investigate the impact of virgin MPs on largemouth bass using a manipulative feeding experiment. The results could provide new insight on commercial fish health when challenged with MPs pollution.