Potencial oxidativo e capacidade de fixação de bactérias heterotróficas e nitrificantes, em diferentes meios de suportes, no cultivo de alevinos de oreochromis niloticus, em sistema de recirculação de água

Abstract

With water as a limiting factor in aquaculture production systems, it is necessary to develop cultivation techniques that enable the rational use of water. The objective of the present work was to evaluate the microbiological fixation capacity of autotrophic and heterotrophic bacteria in different media, as well as their potential for the oxidation of total ammoniacal nitrogen (NTA) in a water recirculation system, in the cultivation of fingerlings of Oreochromis niloticus. In the experiment two treatments were considered, each consisted of two cultivation systems, interconnected to two different mechanical-biological filters, working in a continuous recirculation system. As biological substrate, two media of analysis were evaluated: whole PET bottle cap and; commercial type (BioTECH). 26 L of PET bottle cap and 18.5 L of the commercial medium were used for each treatment. The experiment lasted approximately 112 days. Biological analyzes were carried out every two weeks at the Laboratory of Environmental Microbiology and Fish - LAMAP and, every three days, the analysis of parameters of water quality. The obtained results revealed that both media supports tested have biological fixation capacity, but the characteristics of the support medium influence its performance, since the commercial presented better results in oxidative efficiency.