The antioxidant properties of Spirulina (microalgae) can reduce oxidative stress and neurotoxicity caused by mercury in freshwater mussels

ABSTRACT The aim of this study was to investigate the deleterious effects of mercuric chloride (HgCl2) on the oxidative status and neurotoxicity of Unio ravoisieri, a freshwater mussel, and the potential protective role of Spirulina (SP) as a dietary supplement. The experiment was conducted in a laboratory setting, with two concentrations of HgCl2 (40 and 80 μg/L) administered either alone or in combination with 20 mg/L of SP over a period of seven days. Samples of the mussel's gills and digestive gland were collected following exposure, and levels of antioxidants (CAT, GST), H2O2, GSH, and damage markers (MDA) were measured, along with the activity of the neurotoxicity enzyme, AChE. The results indicated that exposure to HgCl2 resulted in an increase in lipid peroxidation and antioxidant enzyme levels in both the gills and digestive gland. However, the addition of SP to the diet of the mussels restored the levels of antioxidant enzymes, reduced oxidative stress, and decreased neurotoxicity biomarkers (AChE). These findings suggest that SP at a concentration of 20 mg/L can serve as a natural solution to mitigate the toxicity of HgCl2 in freshwater mussels.