Effects of methamidophos on acetylcholinesterase activity, behavior, and feeding rate of the white shrimp (Litopenaeus vannamei)

Evaluación del Riego Ambiental del Insecticida Metamidofos en Bioensayos con Cuatro Organismos Acuáticos no Destinatarios

“…En el langostino Litopennaeus vannamei Boone, 1931, se han encontrado efectos subletales del metamidofos, observán-dose que las alteraciones en el comportamiento fueron más sensibles que la inhibición de la acetilcolinesterasa. En cambio la tasa de alimentación como punto final de lectura, no mostró diferencias significativas en comparación con el control (García de la Parra et al, 2006). En nuestro caso, las respuestas subletales de alteraciones en el comportamiento como nado extraño para P. innesi y de incremento del movimiento opercular para O. mykiss, fueron respuestas más sensibles que la mortalidad en ambos casos.…”

Effects of pesticides and antibiotics on penaeid shrimp with special emphases on behavioral and biomarker responses

“…García de la Parra et al [20] found that AChE inhibition in whiteleg shrimp did not completely depend on the concentration of methamidophos tested, insofar as a slight increase in activity was observed at the highest tested concentration. The maximum level of inhibition was 48.7% in the group exposed to 1.17 mg/L methamidophos, whereas a slight increase in activity was observed at the highest tested concentration (1.35 mg/L).…”

“…Today, the relationship between many exposure-related behavioral alterations observed in the laboratory and their relevance to ecological effects observed in the field remains poorly understood. Several studies in penaeid shrimp have indicated that penaeid shrimp exposed to sublethal concentrations of pesticides show several behavioral alterations, such as restlessness and hyperexcitability, tremor in the appendages, uncoordinated swimming movements, spasms, and violent action of chelate legs [17][18][19][20]. These changes, in general, were more apparent with increasing concentrations of pesticides and were assumed to be a direct consequence of the action of the pesticides on the nervous system.…”

“…Feeding rate has been proposed in several studies as a sensitive indicator of toxic stress in both freshwater and marine species [23][24][25]. García de la Parra et al [20] observed that, in whiteleg shrimp (Litopenaeus vannamei) exposed to sublethal concentrations of 0.66, 0.83, 1.01, 1.18, and 1.35 mg/L methamidophos for 24 h under the experimental conditions of 258C, 32 ppt, 12:12 h light:dark photoperiod, the feeding rate did not show significant differences among treatments. However, Comoglio et al [26] observed that oral exposure to methyl parathion 0.62 and 1.31 mg/g of food for 7 d under the experimental conditions of 248C, 34 ppt, 12:12 h light:dark photoperiod increased the feeding rate in the same species because of the need for increased energy to meet the demand for higher maintenance costs.…”

“…The inhibition of AChE caused by pesticides has been studied in the ventral nerve cord in pink shrimp (Penaeus duorarum) exposed to 1,000 ppb of malathion for 48 h [40], in the nervous tissue of penaeid prawn (Metapenaeus monoceros) exposed to 0.4, 1.2 ppm of phosphamidon for 48 h, to 0.04, 0.12 ppm of methyl parathion for 48 h [41], or to 40 mg/L of methyl parathion for 5 d [17], in whiteleg shrimp (Litopenaeus vannamei) exposed to fenitrothion, azinphosmethyl, methyl parathion, chlorpyrifos, diazinon, and methamidophos [19,20,26,28]. As mentioned above, the mechanism of the toxic action of OPs and CBs is based on the inhibition of the enzyme AChE.…”