Effects of glyphosate-based herbicide on target organs of Astyanax altiparanae in different treatments

Abstract

Glyphosate-based herbicides are extensively utilized in Neotropical agriculture for weed control. Despite their widespread application, concerns regarding water contamination and its consequential impacts on aquatic organisms persist. Notably, there remains a dearth of studies investigating the effects of glyphosate on Neotropical fish species. This study aimed to address this gap by investigating the morphophysiological effects of this herbicide on the liver, gills, and ovaries of Astyanax altiparanae, an ecological and economically important neotropical fish species. Forty individuals were acclimated for 15 days before being exposed to different concentrations of glyphosate (65, 280, and 1000 µg/L) for 28 days. Histological and histometric analyses were conducted on liver, gill, and ovary samples. The findings revealed significant alterations in fish physiology following exposure to glyphosate. The hepatosomatic index increased markedly across all concentration levels, accompanied by dilation of hepatic sinusoidal capillaries, particularly pronounced at higher concentrations. Gill samples exhibited congestion in the central venous sinus, lamellar fusion, and cell death. Additionally, the exposed fish showed a decrease in gonadosomatic index, and the mature females an increase in pre-vitellogenic follicles and a decrease in vitellogenic follicles. This study detected adverse morphophysiological impacts of glyphosate-based herbicides on A. altiparanae, even at permitted concentrations. These findings emphasize the necessity for further research and improved management strategies to mitigate environmental risks associated with herbicide use in aquatic ecosystems.