José Francisco Valério Júnior

This study examined the intestinal morphology and the oxidative status of different tissues of silver catfish (Rhamdia quelen) naturally infected or not by Aeromonas hydrophila and fed diets supplemented with Cymbopogon flexuosus essential oil (EOCF) nanoemulsion (0 - control, 0.25, 0.5, and 1.0 mL of EOCF per kg of diet) for 25 days. Dietary EOCF supplementation did not alter thiobarbituric acid reactive substances levels in the liver; however, in muscle, reduced superoxide anion production. Regarding muscle, the infected group fed with 0.25 mL of EOCF per kg of diet showed higher activity of the total antioxidant capacity compared to the uninfected group. Fish fed 0.25 mL per kg of diet had a survival rate of 72.05%, compared to 17.64% for the infected control. The intestinal fold height was significantly lower in the 0.5 mL EO group compared to the uninfected control group. Fish fed 0.5 and 1 mL per kg of diet presented a lower number of goblet cells than uninfected controls. The addition of 0.25 mL of EO per kg of diet is recommended for use as a feed additive since it increases the antioxidant responses, survival, and the resistance of silver catfish to A. hydrophila infection.

This study evaluated the dietary supplementation of Cymbopogon flexuosus essential oil (CFEO) nanoemulsion in the cutaneous and branchial morpho-adaptive response and its antioxidant potential for silver catfish juveniles naturally infected by Aeromonas hydrophila. Four hundred silver catfish juveniles were randomly distributed in a water recirculation system and fed diets supplemented with CFEO nanoemulsion at concentrations of 0, 0.25, 0.5, 1.0, and 2.0 mL/kg of diet for 25 days. At the end of the experiment, skin, liver, and gill samples [...] ABSTRACT This study evaluated the dietary supplementation of Cymbopogon flexuosus essential oil (CFEO) nanoemulsion in the cutaneous and branchial morpho-adaptive response and its antioxidant potential for silver catfish juveniles naturally infected by Aeromonas hydrophila. Four hundred silver catfish juveniles were randomly distributed in a water recirculation system and fed diets supplemented with CFEO nanoemulsion at concentrations of 0, 0.25, 0.5, 1.0, and 2.0 mL/kg of diet for 25 days. At the end of the experiment, skin, liver, and gill samples

The present study evaluated different levels of the essential oil of Nectandra grandiflora (EONG) in the diet of juvenile Colossoma macropomum. The juveniles (0.75 ± 0.05 g) were fed four experimental diets with differing levels of EONG (0, 0.5, 0.75, and 1.50 mL/kg). After 20 days, the weight, daily weight gain, specific growth rate, and daily feed consumption per fish were highest for the fish fed 0.5 mL EONG/kg, while after 30 days, only the weight and daily feed consumption per fish for that diet remained highest. The viscerosomatic index was highest for the fish fed 0.5 mL EONG/kg while the hepatosomatic index was higher for the groups that received dietary EONG for 30 days. The juveniles fed 1.5 mL EONG/kg showed a proliferative response of the mucous cells in the gills, but the proliferation of these lysozyme- and immunoglobulin-secreting mucosal cells was higher for the skin of the fish of all EONG levels, compared to that of the control fish. The fish fed 0.5 mL EONG/kg had the greatest height and width of intestinal villi. The two highest levels of dietary EONG supplementation (0.75 and 1.50 mL/kg) reduced the hepatocyte dimensions but did not modify the centrolobular vein area. Dietary supplementation with 0.5 mL EONG/kg improved the growth, gut health, and immune response of juvenile C. macropomum.