Resposta morfo-adaptativa e antioxidante de jundiá (Rhamdia quelen) suplementados com nanoemulsão de Cymbopogon flexuosus na dieta

Abstract

The effect of Cymbopogon flexuosus essential oil nanoemulsion on morpho-adaptive response and its antioxidant potential in silver catfish (Rhamdia quelen) naturally infected by Aeromonas hydrophila was studied. For this, silver catfish (n= 400) were randomly distributed in a water recirculation system consisting of 20 polypropylene boxes, 20 fish per box (4 replicates each treatment). Dietary treatments consisted of five experimental diets supplemented with OECF nanoemulsion at the following concentrations: 0; 0.25; 0.5; 1.0 and 2.0 mL/kg of feed. For Twenty-one days, the animals were fed twice a day (09:00 and 19:00 hours) and the parameters of water quality, temperature, dissolved oxygen, pH and ammonia were monitored. At the end of the experiment, silver catfish (n= 8) were anesthetized and euthanized to collect biological material. Liver, gill and skin samples were carefully collected for further morphometric and oxidative state analyses. The variables of water quality remained within the range considered ideal for the espécies. The histomorphometric results of gills and skin showed that the highest levels of nanoemulsion of OECF (1.0 and 2.0 mL/kg of feed) have no effect on skin and gill morphometry of silver catfish naturally infected by A. hydrophila. However, the dietary supplementation of OECF nanoemultion at the concentration of 0.5 m/kg feed showed antioxidant effect on the gills of silver catfish naturally infected by A. hydrophila. Silver catfish naturally affected by A. hydrophila presented structures of the normal hepatic parenchyma, indicating thet the nanoemulsion of OECF has a hepatoprotective effect against infection. Thus, the beneficial effects observed in this study indicate the promising use of OECF nanoemulsion in aquaculture.