Effects of sublethal levels of tributyltin chloride on a new toxicity test organism, Liza saliens (Osteichthyes, Mugilidae)

The histopathological effects of 10−7 and 10−9 M tributyltin(IV)chloride,TBTCl, solutions on differentLiza saliens organs have been studied by light microscope. The fish were sacrificed after 3–4 hincubation in 10−7 M TBTCl solution or after 15 days incubation in 10−9 M solution. The observedhistopathological changes were dose- and time-dependent. The 10−7 M TBTCl concentration resultedin major damage to the gill epithelium, indicating that TBTCl primarily interferedwith the respiration,osmoregulation, acid balance and nitrogenous waste excretion processes. After incubation in 10−9 MTBTCl solution the fish lived 20 or more days, but many of the organs were altered. Thymus atrophy,reduced spleen and altered head kidney were observed. These histological results indicated thatTBTCl interfered with organ immunodefense and altered main metabolic pathways in Liza saliens.The presence of melano-macrophage centers, only in TBT-treated liver and spleen, can be considereda tool to facilitate, with other biomarkers, the detection of alterations by toxicants. Regarding thepancreas activity in 10−7 M solutions, it has been noted that, in the exocrine cells, very few zymogengranuleswere still present and the Langerhans isletsweremore altered. In 10−9M solution the exocrinepancreatic cells had no granules and the islet cells presented degenerative alterations. In addition,TBTCl, which altered the pancreas and gonad morphology, could again be considered an endocrinedisrupter even if biochemical data are still necessary. Finally, the Liza saliens juveniles could beconsidered an interesting biological model for experiments with contaminants, due to their ease ofadaptation to experimental conditions and food chain position.