Acetylcholinesterase activity as a biomarker of exposure to antibiotics and pesticides in the black tiger shrimp (Penaeus monodon)

This study aimed to assess the potentiality to use cholinesterase activity (ChE) in black tiger shrimp (Penaeus monodon) as a biomarker of exposure to 2 antibiotics (enrofloxacin, furazolidone) and 2 pesticides (endosulfan, deltamethrin), commonly used in Vietnamese farms. ChE from muscle and gills was first characterised using three different substrates and specific inhibitors. Results showed that both tissues possess only one ChE which displays the typical properties of an acetylcholinesterase (AChE). In a second part, shrimp (average weight of 8.8-10 g) were fed with medicated-feed containing 4 g enrofloxacin (quinolone) or furazolidone (nitrofuran)/kg for 7 days, or exposed to 3 actual concentrations of endosulfan (0, 0.009, 0.09, 0.9 μg/L) or deltamethrin (0, 0.0007, 0.007, 0.07 μg/L) for 4 days. After treatment, animals were decontaminated during 7 days. We observed that AChE activity in muscle was not significantly affected in shrimp fed with enrofloxacin or furazolidone, while it significantly decreased (up to 28%) in gills of shrimp fed with furazolidone. Following endosulfan and deltamethrin exposure, no significant changes in AChE activity were observed in gills. However, a significant decrease occurred in muscle after 4 days exposure (inhibition of 30% and 49% at 0.9 μg/L endosulfan and 0.07 μg/L deltamethrin, respectively). While muscle AChE activity should be assessed to point out endosulfan or deltamethrin exposure, gill AChE activity impairment could indicate an exposure to furazolidone. The present study underlines the benefits to use AChE as a biomarker of chemotherapeutics as part of an integrated aquaculture management to reach industry sustainability.