Morpho-histochemical Changes in the Gills of Turbot, Scophthalmus maximus L., Induced by Sodium Dodecyl Sulfate

The present article reports the effect on survival as well as morpho-histochemical changes in the gills of juvenile turbot Scophthalmus maximus L., induced by acute action of the anionic surfactant sodium dodecyl sulfate (SDS). First, LC50 at 96 h was found to be 7.5 mg/L of SDS. Second, lots with 20 individuals were exposed to SDS concentrations of 3, 5, 7, and 10 mg/L in order to obtain the exposure time required for 50% mortality of the specimens (384, 190, 12, and 4 h) and surface tension values (60.2, 56, 54.9, and 53.3 mN/m), respectively. Finally, histopathological lesions (clubbing and fusion of the secondary lamellae, hyperplasia and posterior rupture of the respiratory epithelium, destruction and shortening of gill filaments, and the presence of hemorrhagic foci) and histochemical alterations in the distribution of carbohydrates and proteins in the gills of treated specimens were noted. These morpho-histochemical changes in the gills provoked functional disorders (i.e. asphyxia and the loss of osmotic and ionic regulation) that may ultimately play an important role in the mortality of turbots exposed to SDS.