Citral as a dietary additive for Centropomus undecimalis juveniles: Redox, immune innate profiles, liver enzymes and histopathology

The effect of dietary levels of citral in juvenile common snook (Centropomus undecimalis) was evaluated by determining biomarkers of oxidative stress and innate immune system, as well as liver parameters. The fish (2.75 +/- 0.03 g) were fed diets containing different concentrations of citral (0, 0.44, 0.88, and 1.76 mg/kg feed) for 45 days. Results indicate that citral does not cause significant hepatic alterations; nevertheless, this monoterpenoid was able to induce lipoperoxidation in the gills in all concentrations tested. In this context, the altered activity of enzymes such as superoxide dismutase (SOD) in the liver and gills (1.76 mg per kg feed), catalase (CAT) in the liver (0.44; 0.88 mg per kg feed) and gills (all groups), and glutathione-S-transferase (GST) in the liver (0.44 mg per kg feed) and gills (1.76 mg per kg feed) occurred in response to the oxidative damage evidenced. Although dietary levels of citral did not influence the lysozyme activity, we verified that the haemolytic activity of the complement system was excessive in the lowest concentration tested and that the myeloperoxidase activity (MPO) decreased in all groups. Thus, although this monoterpenoid is a diet additive which has already been approved for consumption in other animal species, dietary supplementation with citral for common snook has not improved oxidative parameters and innate immunity of this species.