Toxic effect of olaquindox antibiotic on Eisenia fetida

The purpose of this study is to investigate the toxicity of olaquindox on earthworms by measuring the mortality, morphological changes, weight gain rate of earthworms as well as catalase (CAT) activity in different tissue regions. The results showed that the 48-h median lethal concentration (LC50) was 1.02 mg cm−2 on filter paper and above 4000 mg L−1 in solution, and the morphological changes, especially in the anterior region, showed a progression of damage with increasing olaquindox concentrations. The rate of weight gain of earthworms had no significant differences after 7 days and 14 days exposure to 500 mg kg−1 and 1000 mg kg−1, and decreased significantly after exposure to 3000 mg kg−1 and 5000 mg kg−1. CAT activity in different tissue regions decreased with increasing olaquindox concentrations after 14 days, CAT activity in the anterior was still reduced to 83% of the control value at 500 mg kg−1 and 82% of the control at 1000 mg kg−1.