Reproductive responses of the earthworm (Eisenia fetida) to antiparasitic albendazole exposure

Albendazole (ABZ) is a veterinary drug with a high efficiency against helminths. Here reproductive responses of earthworms Eisenia fetida to ABZ exposure (0, 1, 3, 6, 9 and 12 mg kg−1 soil dry weight) were investigated for 56 d in chronic reproduction test, and deformed sperm were counted and morphological alterations in the seminal vesicles were qualitatively assessed by light and transmission electron microscopy. Results have showed that cocoon number of earthworms was more sensitive to low concentrations of ABZ than cocoon hatching success and hatching survival, showing a significant dose-related decrease in cocoon number at 3, 6, 9 and 12 mg kg−1. In short-time exposure of 14 d, the sperm deformity (%) of earthworms increased at 6, 9 and 12 mg kg−1, and the microstructural alteration in seminal vesicles was also observed at these concentrations, whereas ultrastructural alteration of germ cells, particularly morphology of mitochondria, was observed at 3 mg kg−1 and above, suggesting the high sensitivity of germ cell ultrastructure to low concentrations of ABZ in short-time exposure. The results can provide important information for prediction of ecologically significant toxic effects.