EFFECT OF THE FUNGICIDE TRIFLOXYSTROBIN ON B-ESTERASE ACTIVITY IN TADPOLES OF Scinax nasicus (AMPHIBIA: ANURA)

ATTADEMO, A.M.; JUNGES, C.M.; LAJMANOVICH, R.C.; PELTZER, P.M.; CABAGNA ZENKLUSEN, M.C.; LORENZATTI, E.A.

San Juan

Jornada; SECOND JOINT MEETING OF THE BIOLOGY SOCIETIES FROM ARGENTINA; 2011

EFFECT OF THE FUNGICIDE TRIFLOXYSTROBIN ON B-ESTERASE ACTIVITY IN TADPOLES OF Scinax nasicus (AMPHIBIA: ANURA) In our country, in late 2007, new strobirulin and triazole based biocide formulations were introduced to the market. These components ensure high control of new fungal late season diseases in soybean crops. Trifloxystrobin (TFT), one of these formulations, is characterized by being very toxic to aquatic organisms, with a half-life of 8-24 hours in surface waters. The aim of the present work was to evaluate the effect of TFT on B-esterasase activity (acetylcholinesterase; AChE and butyrylcholinesterase; BChE) on tadpoles of Scinax nasicus (Amphibia: Anura) under controlled laboratory conditions. Acute toxicity bioassays (24 and 48 h) were performed using sublethal concentrations of TFT (0.0312; 0.0625; 0.125 and 0.250 mg/L) and a control, with the respective replicates. The commercial product used was Flynt® (50% a.i., Bayer CropScience S.A., Argentina). Seven larvae, Gosner stage 39-42, per container and per treatment were exposed under a light-dark (12:12) photoperiod at 25 ± 2°C. Brain AChE and muscle BChE activities were determined for each individual using routine techniques. The results obtained indicate an inhibition of BChE activity (range 1.94 ± 0.35 to 2.58 ± 0.19 nmol min -1  mg-1 protein) at all TFT concentrations assayed (P< 0.05) at 48 h of exposure with respect to control (3.09 ±0.46 nmol min -1 mg-1  protein). A similar trend was observed for AChE, but no statistically significant differences were observed (P > 0.05). These preliminary results suggest a negative effect of TFT on B-esterase activity on tadpoles of S. nasicus. *The present work is part of the project CAI+D (UNL) Type II PI 14-80