Fatty acid composition, enzyme activities and metallothioneins in Donax trunculus (Mollusca, Bivalvia) from polluted and reference sites in the Gulf of Annaba (Algeria): Pattern of recovery during transplantation

The gulf of Annaba, the most important touristic and economic coastal zone located in Northeast Algeria, is contaminated by several pollutants from urban, agricultural, harbor and industrial activities. Elevated levels of heavy metals were detected in a locally prevalent edible mollusk Donax trunculus (Bivalvia, Donacidae) widely used as a sentinel species for the assessment of marine pollution. The present work aims to measure the difference between two localities, one being full of different pollutants (Sidi Salem) and the other being relatively clean (El Battah) and to evaluate the ability of D. trunculus to overcome the environmental stress during a transplantation experiment by a determination of fatty acid profile, the enzymes activities and the level of metallothioneins (MTs), a biomarker of metallic contamination. Adults of D. trunculus were collected at Sidi Salem (contaminated site) and transplanted into El Battah (reference site) for 21 days in cages (60 × 60 × 60 cm with a 2 mm mesh). Biochemical analyzes were conducted at different times (0, 7, 14 and 21 days). At 0-day experiment: the rate of the fatty acids, the enzymes activities and MT levels at the site of Sidi Salem (polluted site) were significantly different from those of El Battah. During the transplantation a gradual restoration of fatty acids rates, enzymes activities and MT levels was observed. At the end of the period of transplantation, the values are comparable to those of El Battah. A two-way ANOVA (time, site) on data revealed significant effects of time and site. Overally, D. trunculus is able to induce its detoxification system and to restore relatively rapidly the status of individuals from the reference site (El Battah).