Nanoplastics impair the intestinal health of the juvenile large yellow croaker Larimichthys crocea

Microplastics (MPs) have become a severe concern in marine environment worldwide. Micro-polystyrene particles have been proved to accumulate in vivo and caused disorders of digestion, antioxidant system, immunity and intestinal microflora, but little is known about the effects of nano-polystyrene (nano-PS). In order to understand response mechanism of marine fish to nano-PS, the effects of nanoplastics on the intestinal health and growth performance of the juvenile Larimichthys crocea were investigated. After 14-d exposure, the reduced digestive enzyme activities indicated that nano-PS had a negative impact on the digestion and absorption of juvenile fish. Moreover, analysis of the intestinal microbiota showed that the proportion of the three-dominant bacterial phyla (Bacteroidetes, Proteobacteria and Firmicutes) in the gut changed significantly, accompanied by a significant increase of potentially pathogenic bacteria (Parabacteroides and Alistipes). In addition, lysozyme activity and specific growth rate (SGR) were significantly reduced, and total mortality of juvenile fish was significantly increased. Overall, nano-PS exposure was harmful for the health of juvenile fish, which might threaten their population in the long term.