Evaluation of sublethal biomarkers in Litopenaeus vannamei on foodborne exposure to methyl parathion

Abstract

Sublethal effects of the foodborne exposure to methyl parathion (0.62 and 1.31 µg * g-1) on juveniles of Litopenaeus vannamei using integrated biochemical (AChE and Na+/K+-ATPase) and physiological (feeding rate, egestion rate and hepatosomatic index) biomarkers were evaluated. The HI was significantly higher in controls than treatments. The FR was significantly lower in control than pesticide treatments while no significant differences were detected in the ER. AChE activity of controls was significantly higher than in the pesticide treatments (control=0.11±0.02; solvent control=0.11±0.025; 0.62=0.07±0.01; 1.31=0.08±0.02 as µM * min-1 * mg protein-1). The Total-ATPase activity was significantly lower in the controls than in the pesticide treatments (control=77.90±12.41; solvent control=83.69±22.05; 0.62=110.03±22.17; 1.31=121.54±19.84 µM Pi /h per mg protein). Mg2+-ATPase activity was significantly higher in treatments than controls (control=65.14±10.76; solvent control=75.12±21.10; 0.62=100.53±20.97; 1.31=108.94±17.26 µM Pi * h-1 * mg protein-1). Finally, the results obtained for the Na+ /K+-ATPase activity, control and 1.31 were significantly different than solvent control and 0.62 (control=14.06±2.63; solvent control=7.30±4.13; 0.62=7.60±3.81; 1.31=13.42±2.88 µM Pi * h-1 * mg protein-1). The results in this study showed that pulse exposures to methyl parathion via food could elicit measurable effects on the marine shrimp Litopenaeus vannamei, indicating that foodborne exposure can be a reliable toxicological procedure and, if combined with pulse exposures, it could also simulate more realistic exposure scenarios.