Histopathological evaluation of two Blennius fishes exposed to microplastics via feeding

• Autor(a) principal: Almeida, Diogo Samuel Martins
• Data de Publicação: 2017
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/29989
• topic: microplastic; gobies; histopathology; ingestion; contaminant release; bioavailability; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia do Ambiente

The microplastic particles have dramatically increased in marine environments, emerging the concern of their potential adverse effects on marine biota, among others. These biological adverse effects of microplastics may result not only in physical harm such as internal abrasions and blockages, but also in an entrance vector of contaminants into marine organism. Therefore, the overall aim of this study was to assess the health status of two gobies (Blennius pholis and Blennius galerita) exposed to microplastics, both coated and uncoated with antifouling paints (i.e. common source of metals), via feeding for a month. For that purpose, multi-organ histopathological assessment (i.e. gills, liver, kidney and digestive tract) was carried out qualitatively and semi-quantitatively in gobies, as well as histochemical evaluation. The results showed no sign of microplastics ingestion, suggesting that these gobies were not able to ingest used microplastic spheres. Accordingly, no gross histological alterations were recorded in both fish species exposed to microplastics. Similarly, regardless the pathway of contaminants exposure (i.e. by ingestion or waterborne), animals exposed to contaminated microplastics presented similar histopathological levels than those treated with uncontaminated microplastics, or even than control. The affection degree of each target organ revealed gills and liver as the most affected organs following by kidney, digestive tract and spleen. Lamellar lifting, fat vacuolation of hepatocytes and melanomacrophage centers were the most prevalent alterations noticed in gills, liver and whole-body of fish, respectively. These findings may suggest that other factors, even natural occurrence, could be the cause of these mild histopathological alterations. Moreover, the use of Blennius gobies in multi-organ histopathology showed to be a suitable organism and tool for assessing the potential adverse effects caused by microplastics and their potential role as contaminants entrance. Therefore, smaller microplastic particles, both contaminated and uncontaminated, should be tested in gobies in order to clarify and evaluate their potential adverse effects via feeding.