The combined effects of lipoic acid and sodium acetate on metabolism, redox balance, and utilization of yolk reserves of Artemia sp. nauplii

Abstract

Lipoic acid (LA) has been an antioxidant with proven benefits in different species of productive interest. However, there is evidence of the effect of LA as a growth repressor and, consequently, of zootechnical performance. This study evaluated the effect of the co-administration of LA and short-chain fatty acid, sodium acetate (SA), as an additional source of energy on the utilization of yolk nutrients in Artemia sp. nauplii. A factorial experiment was designed with four levels of LA (0.0, 0.05, 0.5, and 5.0 μM) and four levels of SA (0.0, 2.0, 4.0, and 8.0 mM). Over 24 h, with sampling every 6 h, the total ammoniacal nitrogen (TAN) concentration in water, the concentration of protein, triglycerides, glucose, and the antioxidant capacity (ACAP) was evaluated in the artemia. The electron transporter system (ETS) activity and production of reactive oxygen species (ROS) in vivo were also recorded. Both LA and SA decreased TAN production. At 18 h, LA caused significant decreases in glucose content at the concentrations of 0.5 and 5.0 μM. On the other hand, SA preserved protein values in a dose-dependent manner at 12 h. Regarding ACAP, the LA showed ambivalent effects on this parameter, promoting a higher ACAP at 6 h; however, it promoted a more pro-oxidant state in the metanauplii at 24 h. While the ETS activity increased at 6 h, as an effect of the SA and LA administered separately, the co-administration of LA and SA revealed a possible antagonism that caused a decrease in the ETS activity by the action of LA. As for ROS, a decrease in production rates was found with the administration of LA, which was more noticeable at LA concentrations within the 0 and 2 mM levels of SA from 18 h onwards. Finally, the final energy content showed a scenario of the preservation of the energy reserves of artemia nauplii with the addition of SA. As expected, the LA negatively affected the energy content of the animals; however, the treatment with the highest energy content was the one that received 0.05 μM LA and 8.0 mM SA, suggesting the possibility of using these compounds together in order to compensate the side-effects of LA.