Antioxidant responses and oxidative damage in shrimp Litopenaeus vannamei: Effects of antioxidant supplementation and use of biofloc technology
Author: Átila Clivea da Silva Martins (Currículo Lattes)
Supervisor: Dr Jose Maria Monserrat
Co-supervisor: Dr Wilson Francisco Britto Wasielesky Junior
Abstract
In aquaculture, the increase in intensification is directly linked to the application of new technologies that increase the volume of production while having the least impact on the environment surrounding the production. Thus, biofloc technology emerges as a method in which water quality treatment is carried out inside the breeding tank so that photoautotrophic (microalgae), autotrophic (nitrifying bacteria) and heterotrophic (heterotrophic bacteria) organisms recycle nitrogen compounds that may come to be toxic to the shrimp Litopenaeus vannamei, in addition to being able to transform ammonia into bacterial biomass that will serve as a protein and lipid source for the shrimp, which may reduce feed costs.With increased density in the breeding system, it is necessary to increase the biochemical resistance of the bred animal, for this purpose this work presents in three chapters means of supplementation with antioxidant lipoic acid (LA) that helps in the biochemical antioxidant response as a mechanism to improve the good shrimp Litopenaeus vannamei. First, through biochemical analyzes such as glutathione S-transferase (GST) activity, reduced glutathione concentration (GSH), total antioxidant capacity against peroxyl radicals (ACAP) and levels of lipid peroxidation (TBARS) in gills, hepatopancreas and shrimp muscle , observing that the bioflocus induces increased GST activity in gills, increased concentration of GSH in muscle,increases the total antioxidant capacity in muscle and reduces levels of lipid peroxidation in hepatopancreas. The second work, was applied nanoencapsulated lipoic acid (NCLA) and empty capsule (NC) in the ration, in clear water and in water with biofloc in which it was observed that NCLA induced increased GST activity in the hepatopancreas. The concentration of GSH was higher in muscle than in gills and hepatopancreas. The antioxidant capacity also showed a tissue-specific pattern, with hepatopancreas with greater antioxidant capacity with no evident action of NCLA's performance against peroxyl radicals. Levels of lipid peroxidation were lower in the muscle, with a marked effect of NCLA. In the groups with NCLA there was an increase in the percentage of granular hemocytes, cells with higher amounts of immunocompetent components. At work 3,it was observed that AL is able to increase the antioxidant capacity in the biofloc, analyzed by determining the total antioxidant capacity against peroxyl radicals (ACAP), mainly for a concentration of 10 μM (2.06 mg of AL in 1 L of distilled water).