Gill injury after treatment with mebendazole on mullets mugil liza

Abstract

Mebendazole (MBZ) is a drug commonly used in human and veterinary medicine against parasitic diseases. This study was designed to identify the lethal dose of MBZ for the host individual when MBZ was delivered at high concentration. We exposed Mugil liza to MBZ at either zero, 1, 10, 100, or 200 mg/L, or 1 or 5 g/L, utilizing a bath treatment with a duration of 24 hours. We found no mortal- ity in any treatment dose. Surprisingly, fish that received 10 mg/L or more showed changes in gill structure, such as moderate and severe hyperplasia, focal necrosis, telangiectasia with rupture of the pillar cells, escamosa metaplasia and increased mitotic activity. There were no significant lesions recorded in the other organs examined. MBZ already has been identified as an agent of oxidative stress. It is suggested that necrosis is possibly caused by oxidative damage or even direct eYect of the MBZ. The hyperplasia observed was likely reactive response. MBZ therapeutic baths in con- centration equal to or higher than 10 mg/L may cause gill damage, which can aYect the respiratory capacity and osmoregulation.