European Journal of Biomedical and Pharmaceutical Sciences

EVALUATION OF AN ACUTE ORAL GAVAGE METHOD FOR ASSESSMENT OF IMIDACLOPRID TOXICITY IN TERRESTRIAL AMPHIBIAN HOPLOBATRACHUS TIGERINUS

Padmaja B., Vivek C. H.*, Usha Rani K. and K. Veeraiah

ABSTRACT

Development of an acute oral toxicity test with a terrestrial‐phase amphibian was considered necessary to remove the uncertainty within the field of agrochemical risk assessments. The present study intended to help fill the gap on the scarcity of information concerning the imidacloprid toxicity impact on bullfrog. The Indian bullfrog (Hoplobatrachus tigerinus) was selected for use as it is a representative of the family Dicroglossidae and historically this species has been used as an amphibian test model species. Prior to definitive study, oral gavage method was applied with Imidacloprid. The test pesticide subsequently tested with both male and female juvenile bullfrogs in comprehensive acute oral median lethal dose (LD50) studies. The primary endpoint was mortality, whereas behavioral responses, food consumption and body weight were used to evaluate indications of sub-lethal toxicity (secondary endpoints). The results clearly indicates that the acute oral LD50 (95% fiducial interval) for 24, 48, 72 and 96 h in static method obtained 213.8 mg/L, 195.34 mg/L, 172 mg/L, 165 mg/L. Therefore, our data suggest that the per cent mortality and probit mortality increased with the increase in concentration and the LD50 values decreased with the increase in exposure period of toxicant. Based on the results of these studies, the methodology for the acute oral gavage administration of test items to terrestrial‐phase amphibians was demonstrated as being a practical method of providing data for risk assessments.

Keywords: Imidacloprid, Bullfrog, Acute oral toxicity, Risk assessment.