Lipoic acid modulates energetic metabolism and antioxidant defense systems in Litopenaeus vannamei under hypoxia/reoxygenation conditions

Lipoic acid (LA) is a known potent antioxidant, which has shown positive effects on energy metabolism. In this study, our objective was to evaluate the protective effects of LA on metabolic and biochemical alterations in hypoxia/reoxygenation injury (H/R) in shrimp (Litopenaeus vannamei). Two experimental groups were evaluated: non-supplemented and supplemented with LA (1% of body weight). The groups were evaluated after different periods of exposure to hypoxia (6 and 24 h) at 1.5 mg O₂ L⁻¹ and different periods of reoxygenation (0, 1, and 3 h). When the animals were supplemented with LA, glucose levels were decreased in the hemolymph and increased in the muscle tissue under H/R conditions. Furthermore, no change in lactate dehydrogenase (LDH) activity was observed, and lactate levels were either decreased or unchanged. In biochemical analyses related to oxidative stress, a protective effect of LA was shown against lipid peroxidation induced by H/R after 24 h of exposure. LA supplementation was shown to increase antioxidant capacity more effectively during reoxygenation. LA modulated glutathione-S-transferase (GST) activity differently according to H/R exposure time and the available oxygen concentration. Our results show that LA positively modulated energetic aspects and oxidative stress under H/R conditions. In the context of disturbance of oxygen concentration, LA was effective as a supplement against damage induced by hypoxia. This study corroborates the unique properties of LA against stressful situations and may contribute positively to existing problems in shrimp farming.