14 January 2022

Plastic pollution reduces fertility of zebrafish

Fertility

Exposure to plastic nanoparticles in a generation of zebrafish causes changes in the metabolome and gut microbiota as well as a lower survival of embryos produced by exposed parents. This indicates that long-term effects may impact reproductive capabilities and potentially population dynamics; essential parameters that are often missed by short-term studies.

Zebrafish

Those are the conclusions of a newly published study that three researchers from the Center for Evolutionary Hologenomics have contributed to. Alongside other Danish colleagues, they studied the effects of plastic pollution on a full generation of zebrafish.

A novel multi-omics approach

“It’s the way the multi-omics approach is applied that is novel. The study addresses in a holistic way both short term and the less studied long-term effects of the plastic nanoparticles during a complete life cycle of zebrafish. The multi-omic approach consisted of gene expression analysis, metabolomics, microbiota analysis, condition factor and reproductive success measurements which, all put together, were aimed to capture the effects of plastic nanoparticle exposure on the extremely useful model organism that zebrafish is.” Says PhD fellow Eiríkur Andri Þormar at Center for Evolutionary Hologenomics who is one of the researchers behind this study.

Zebrafish as an ideal model to study plastic pollution

The researchers took advantage of the zebrafish model's short life span to record a range of health-related impacts induced by exposure to plastic nanoparticles during a full generation. Short- and long-term adverse effects were investigated in the zebrafish model organism using a holistic multi-omics approach. 

This study demonstrates how studying zebrafish with its short generation time represents the ideal holistic model to investigate adverse impacts of plastic nanoparticles in vertebrates. 

“My main task and focus in the study was on effects of long-term exposure of nanoplastic particles on the zebrafish microbiota, where I performed the sampling of the tiny zebrafish guts, lab processing and analysis of the microbiota data.” Says PhD fellow Eiríkur Andri Þormar at Center for Evolutionary Hologenomics.

Environmental consequences

The exposure concentrations used in this study ranged from environmentally relevant to magnitudes higher. It is expected that the concentration of plastic nanoparticles rises in the environment with time. Thus, with just a tenfold increase, there may be, according to this study, a long-term effect on the reproductive capacity on species population level leading ultimately to detrimental consequences not only for fish but for all aquatic organisms and top predators, disrupting food chains and negatively impacting biodiversity.

“Although the results do suggest that the zebrafish are negatively impacted on many levels, with both short and long-term exposure of plastic nanoparticles, they can't tell us much about how plastic nanoparticles would affect us humans. However, the results do clearly highlight the need to further study the possible detrimental effects of nanoplastic particles on the environment, its inhabitants (humans included) and ecological processes. This is especially relevant considering the long-term effects, which is one of the key points in this study, since those more accurately represent the real-life environmental situation, compared to short-term effects, which most studies of this kind have focused on thus far.” Ends PhD fellow Eiríkur Andri Þormar.

Read the article published in Journal of Hazardous Materials here.

Contact

PhD fellow Eiríkur Andri Þormar, eirikur.andri@sund.ku.dk