Deleterious effects of two pesticide formulations with different toxicological mechanisms in the hepatopancreas of a freshwater prawn

LAVARÍAS, S.M.L. ; COLPO, K.D. ; LANDRO, S.M.2., ; AMBROSIO, E.S. ; RODRIGUES CAPÍTULO, A. ; ARRIGHETTI, F.

CHEMOSPHERE

PERGAMON-ELSEVIER SCIENCE LTD

Lugar: Amsterdam; Año: 2021

0045-6535

The aim of this study was to evaluate the effects of the pyrethroid cypermethrin (CYP) and the last generation pesticide spirotetramat (STM) on the prawn Macrobrachium borellii. Initially, the 96-h LC50 was determined in adult prawns. Then, to determine metabolic disorders that are usually proposed as biomarkers of effect, prawns were exposed to sublethal concentrations of CYP and STM (5% and 20% of the 96-h LC50 values) for four days. Total protein and uric acid content, glutathione S-transferase (GST) activity, levels of lipid peroxidation (LPO), and protein oxidation (PO) were evaluated in the hepatopancreas. Additionally, the presence of histopathological changes, lipofuscins (LF), and neutral lipids (NL) accumulation were analyzed. The 96-h LC50 values were 0.12μg /l and 8.2mg /l for CYP and STM, respectively. The total proteins and uric acid content of the hepatopancreas were not significantly affected by the treatments (p > 0.05). STM significantly affected the GST activity only at the highest concentration (p < 0.001). However, LPO and OP levels were affected by the lowest concentrations of both pesticides (p < 0.003). CYP and STM produced dose-dependent histological damage in the hepatopancreas as was indicated by the histopathological index (HI). This analysis showed predominantly regressive changes such as atrophy in the epithelium of the digestive tubules and, necrosis of the epithelial cells. Among the progressive changes, an increased number of R-cells, as well as cytoplasmic vacuolization, were observed. The accumulation of LF showed a dose-dependent response while for NL the highest accumulation was observed in prawns exposed to the lowest concentration of both pesticides. Although the integrated biomarker index IBRv2 results indicated that both pesticides had an impact on the health status of M. borrellii, CYP showed the highest response. Likewise, the IBRv2 indicated that the HI, the LF, and NL contents represented the most sensitive responses in prawns exposed to CYP, while LF was the most sensitive response in prawns exposed to STM. These results serve as a stepping-stone to evaluate the potential role of M. borellii as a bioindicator of contamination by agrochemicals that entail different toxicity mechanisms.