Short-term exposure of European sea bass (Dicentrarhus labrax) to nitrate. Effects on skin morphology and skin mucous cells

Abstract

In the present study the effect of two levels of nitrate on the skin morphology and particularly on the number and diameter of skin mucous cells of sea bass were examined histologically. A softwarecontaining a visual basic script macro, that allowed quantification of skin parameters, was used to analyze the skin tissue sections. In total 45 sea bass (mean weight 155.6g±10.3g SD) were divided into 3 groups and placed into nine 100 litter tanks (3 replicates in each group). In the water of three tanks (Group A) nitrate was added toapproximate 100 ppm final concentration, in the next 3 tanks (Group B) nitrate was added to approximate 700 ppm final concentration, while the fish in the remaining 3 tanks (Group C) kept as controls. During the experimental period (48 hours) the tank water was constantly aerated. At the end of the experimental period 3 fish per tank (9 per group) were sampled and examined. The fish of the group that were maintained in the highest concentration of nitrate exhibited significantly (P0.05). The increased number of the mucus cells in the skin is probably the reaction of the fish to this stressful condition.

Keywords

• Dicentrarhus labrax
• nitrate
• fish
• mucous cells