In vivo studies on bioavailability, toxicity, and antioxidant defense of organic selenium-enriched microalga biomass in Wistar rats

Selenium, an essential trace element, is known to have several health benefits. Dietary selenium sources include both organic and inorganic forms, however organic forms are more digestible and less toxic than inorganic forms. Microalgae have been considered as food in different parts of the world for decades. They recently gained popularity in the food and nutraceutical industry because of the presence of highly valued compounds. The current study investigates the efficacy of organic selenium-enriched edible microalga Nannochloropsis oceanica CASA CC201 as a dietary selenium supplement by testing its bioavailability, toxicity, and antioxidant properties in Wistar rats. The study showed that organic selenium-enriched N. oceanica CASA CC201 was not toxic to the animals. Further, organic selenium-enriched microalga promoted the growth of the organism significantly. It helped to reduce cholesterol and low-density lipoprotein (LDL) compared to the control. No abnormal pathological conditions were observed in any experimental group during the study. A significant accumulation of selenium was observed in the Serum and tissues of the organic Se-fed group. The organic Se-fed group showed significantly lower oxidative stress marker malondialdehyde (MDA) levels than in other tested groups. In addition, catalase activity in the liver was higher in the organic-Se-fed group than in the oxidative stress-induced group fed with the known antioxidant silymarin. The study demonstrated that the organic Se-enriched N. oceanica CASA CC201 could be an effective dietary Se supplement.