Biorremediação em ambientes límnicos eutrofizados com a utilização de Dendrocephalus brasiliensis Pesta, 1921 (Crustacea Anostraca Thamnocephalidae) e seu aproveitamento na aquicultura

• Autor(a) principal: Tenório, Ruy Albuquerque
• Data de Publicação: 2011
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da Universidade Federal de Alagoas (UFAL)
• Texto Completo: http://www.repositorio.ufal.br/handle/riufal/1346
• topic: Química e Biotecnologia; Branchoneta; Cyanobacteria; Eutrofização; Hidrolisado proteico; Organismos filtradores; Eutrophication; Filter-feeding organisms; Hydrolysate proteic; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA

Planktonic microalgae’s bloom can cause losses in aquaculture outputs or even damages in areas of cultivation because of the depletion of oxygen dissolved in water, being favored by the addition of chemical substances that are rich in phosphorus and nitrogen configuring the aquatic cultural eutrophication. This paper aimed to verify the potentiality of the Dendrocephalus brasiliensis (branchoneta) in the phytoplankton’s top-down control and such a protein source in aquaculture. In the experiment, that consisted of six treatments (0, 20, 40, 60, 80 e 100 bc.L-1) with four repetitions, eutrophicated water from the CHESF fish station was used, in aquariums, analyzing the interferences of the branchoneta (bc) in the algae’s composition and in the water’s quality throughout one infradian cycle. To perceive the brachoneta’s biofiltration qualitative and quantitative analyses of phytoplankton found in its intestinal content and in water samples were made, and to identify its food preference, Manly´s was used. The trophic state (ET) of water was analyzed using the Nygaard, Carlson indices modified by Lamparelli, Hâkanson and Boulion. Enzymatic experiments were carried out with the branchoneta’s extract and for the proteolytic activities unspecified and specific substrates were used. The output of hydrolyzed protein from branchoneta (HPB) occurred by enzymatic autolysis in different concentrations, calculating the percentage of hydrolysate protein in the reaction. In the electrophoresis and zymogram gels with concentration and separation in 4% and 12,5% respectively were used. According to the results 92 species of phytoplankton were identified. The cyanobacteria Anabaena sp. and Geitlerinema amphibium are among the preferred species in the branchoneta’s feed. It was identified that with 6 h there was efficiency of filtration in the densities of 80 and 100 bc.L-1. Also the change from eutrophic’s ET to oligotrophic by the Nygaard’s index was observed. The analysis of chlorophyll type a testified changes in water’s ET to an inferior level, using Hâkanson and Lamparelli. Notwithstanding, alteration of ET for the indices that use phosphorus did not occur, despite the fact that they differ statistically. In the treatment with 100 bc.L-1 the small values of chlorophyll a (15,07 ± 3,35 μg.L-1) and the bigger values of ammonia (3.463,27 ± 277,42 μg.L-1), phosphorus amount (1.867,84 ± 207,19 μg.L-1) and nitrite (7,57 ± 2,43 μg.L-1) occurred. Even increasing the levels of nitrogen and phosphorus in the water there was a diminution in the levels of chlorophyll a, probably because of the branchoneta’s filter feeding over the population of phytoplankton. About the HPB, 79,67% of crude protein that constitutes a good source of essentials amino acids with values that are bigger than the values of flours of menhaden and soya, and with chemical score of amino acids that fulfill the necessity of youth carnivore shrimps. The conclusion is that the biomaniputation of D. brasiliensis on the top-down control of phytoplankton occurred in an efficient way, characterizing the bioremediation on eutrophicated ambient with changes of ET. The HPB shows a potential to be inserted in rations like a protein component, and even like a flavor booster because it shows attractive amino acids with umami flavor.