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

A dosage-effect assessment of acute toxicology tests of microplastic exposure in filter-feeding fish

Abundant microplastics was found in aquatic ecosystem and aquatic organisms, which raised many concerns in public. Silver carp (Hypophthalmichthys molitrix), a species filter-feeding planktivorous fish, feed on particle between 4 and 85 μm in size, and the respiratory process works together with feeding mechanism when filtering plankton from water. The aim of this study was to assess the physiological response of silver carp exposed to 5 μm polystyrene microspheres during 48 h of exposure followed by 48 h of depuration through the gill histology, and oxidative stress biomarkers in intestine. The results revealed that microplastics can pass through the whole digestive tract of silver carp and be excreted by feces. Low microplastic concentration (80 μg/L) induced oxidative stress and up-regulation of TUB84 and HSP70 gene in intestine, and silver carp have ability to recover after the exposure to microplastic was removed. High microplastic concentration (800 μg/L) definitely cause significant damage to gills and intestines, in this situation, far beyond the possibility of fish own repair, and even when the threaten removed, silver carp can't recovery soon. Our studies assessed the dosage-effect relationship with physiological stress on silver carp when exposure to microplastics.

A preliminary study of the association between colonization of microorganism on microplastics and intestinal microbiota in shrimp under natural conditions

The microplastics pollution in wild aquatic organisms has been described by many studies. However, few studies focused on the farmed ones and MPs impacts on their gut microbiota under natural conditions. Here, we present the first detection of MPs in shrimp ponds and Litopenaeus vannamei. We also globally, firstly and preliminarily investigate the association between colonization of microorganism on MPs and intestinal microbiota under natural conditions. Microplastics (5129 ± 1176 items/kg d.w.) in sediments were mainly pellets, mostly white and blue, and in size less than 1 mm. Microplastics (14.08 ± 5.70 items/g w.w.) in shrimps were higher than that in mostly wild aquatic organisms and positively correlated with that in sediments. Blue fibers in small size (<0.5 mm) were dominant in shrimps. The bacterial communities and their microbial function on MPs were similar with that in shrimp gut, with higher diversity and richness in bacteria communities colonized on MPs. Network analysis demonstrated that the colonization of microorganism on MPs were associated with shrimp intestinal microbiota. Results suggest that except for toxicity reported previously, the effects on intestinal microbiota induced by MPs were possibly because of the biofilm on their surfaces as well, causing notable impacts on aquatic animals.

Immunotoxicity and intestinal effects of nano- and microplastics: a review of the literature

BACKGROUND

Together with poor biodegradability and insufficient recycling, the massive production and use of plastics have led to widespread environmental contamination by nano- and microplastics. These particles accumulate across ecosystems - even in the most remote habitats - and are transferred through food chains, leading to inevitable human ingestion, that adds to the highest one due to food processes and packaging.

OBJECTIVE

The present review aimed at providing a comprehensive overview of current knowledge regarding the effects of nano- and microplastics on intestinal homeostasis.

METHODS

We conducted a literature search focused on the in vivo effects of nano- and microplastics on gut epithelium and microbiota, as well as on immune response.

RESULTS

Numerous animal studies have shown that exposure to nano- and microplastics leads to impairments in oxidative and inflammatory intestinal balance, and disruption of the gut's epithelial permeability. Other notable effects of nano- and microplastic exposure include dysbiosis (changes in the gut microbiota) and immune cell toxicity. Moreover, microplastics contain additives, adsorb contaminants, and may promote the growth of bacterial pathogens on their surfaces: they are potential carriers of intestinal toxicants and pathogens that can potentially lead to further adverse effects.

CONCLUSION

Despite the scarcity of reports directly relevant to human, this review brings together a growing body of evidence showing that nano- and microplastic exposure disturbs the gut microbiota and critical intestinal functions. Such effects may promote the development of chronic immune disorders. Further investigation of this threat to human health is warranted.