Qualidade da água e caracterização do perifíton na produção de juvenis de tilápia do nilo em viveiros escavados com o uso de substratos
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Data
2019-08-12
Autores
Rodrigues, Roberta Almeida
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Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste trabalho foi avaliar a influência da produção de perifíton na qualidade da água em viveiros escavados de produção intensiva (7 t/ha1) de juvenis de tilápia do Nilo (Oreochromis niloticus) com baixa renovação da água (6,2% dia-1). O experimento foi iniciado em maio/2018 a julho/2018 com alevinos de tilápia do Nilo com peso médio de 2 gramas e foi encerrado quando os peixes atingiram o peso médio de 35 gramas. Cada unidade experimental foi representada por um viveiro escavado de 130 m2, com água de entrada e saída independentes. O delineamento experimental constou de dois tratamentos e três repetições, sendo testada presença ou ausência de substrato nos viveiros escavados. No tratamento com inclusão de substrato atrator, foram instalados módulos compostos por hastes de bambu ocupando 50% da área superficial do viveiro. Em cada viveiro, foram inseridos módulos de substratos desprotegidos e protegidos dos peixes. Os resultados mostraram que a temperatura, condutividade elétrica, transparência, pH e alcalinidade da água não foram alterados pela produção de perifíton nos substratos de bambu na produção de perifíton nos viveiros escavados no cultivo de juvenis de tilápias do Nilo. A comunidade perifítica presente nos substratos de bambu nas condições deste experimento foi classificada como heterotrófica durante todo o período experimental. A proporção na inserção de substratos de bambu em 50% da área de superfície da água dos viveiros foi suficiente para proporcionar a manutenção da qualidade da água nos viveiros escavados de produção intensiva de juvenis de tilápia do Nilo com baixa renovação da água. Embora o tratamento com substrato tenha tido uma biomassa final de peixes estocados 12% maior em relação ao tratamento sem substrato, o crescimento da biomassa perifítica foi capaz de manter os níveis de concentração de nutrientes semelhante em ambos os tratamentos (com e sem substratos).
The objective of this work was to evaluate the influence of the insertion of the bamboo substrate on the water quality in intensive nursery (7 t/ha1) of juvenile Nile tilapia (Oreochromis niloticus) with low water renewal (6.2% Day-1). The experiment was started in 2018/May to 2018/July with Nile tilapia fingerlings with an average weight of 2 grams and was closed when the fish reached the average weight of 35 grams. Each experimental unit was represented by a nursery excavated of 130 m2, with water of independent entrance and exit. The experimental design consisted of two treatments and three replicates, being tested the presence or absence of substrate in the excavated nurseries. In the treatment with inclusion of substrate attractor, modules composed of bamboo stems occupying 50% of the surface area of the nursery were installed. In each nursery, substrate modules were inserted unprotected and protected from fish. The results showed that the temperature, electrical conductivity, transparency, pH and alkalinity of the water were not altered by the inclusion of bamboo substrates in the production of periphyton in nurseries excavated in the cultivation of Nile tilapia juveniles. The periphytic community present in the bamboo substrates under the conditions of this experiment was classified as heterotrophic throughout the experimental period. The proportion in the insertion of bamboo substrates in 50% of the water surface area of the nurseries was sufficient to provide the maintenance of water quality in the intensive nursery of Nile tilapia juveniles with low water renewal. Although the substrate treatment had a final biomass of fish stored 12% higher than the substrate treatment, the growth of the periphytic biomass was able to maintain similar levels of nutrient concentration in both treatments (with and without substrates).
The objective of this work was to evaluate the influence of the insertion of the bamboo substrate on the water quality in intensive nursery (7 t/ha1) of juvenile Nile tilapia (Oreochromis niloticus) with low water renewal (6.2% Day-1). The experiment was started in 2018/May to 2018/July with Nile tilapia fingerlings with an average weight of 2 grams and was closed when the fish reached the average weight of 35 grams. Each experimental unit was represented by a nursery excavated of 130 m2, with water of independent entrance and exit. The experimental design consisted of two treatments and three replicates, being tested the presence or absence of substrate in the excavated nurseries. In the treatment with inclusion of substrate attractor, modules composed of bamboo stems occupying 50% of the surface area of the nursery were installed. In each nursery, substrate modules were inserted unprotected and protected from fish. The results showed that the temperature, electrical conductivity, transparency, pH and alkalinity of the water were not altered by the inclusion of bamboo substrates in the production of periphyton in nurseries excavated in the cultivation of Nile tilapia juveniles. The periphytic community present in the bamboo substrates under the conditions of this experiment was classified as heterotrophic throughout the experimental period. The proportion in the insertion of bamboo substrates in 50% of the water surface area of the nurseries was sufficient to provide the maintenance of water quality in the intensive nursery of Nile tilapia juveniles with low water renewal. Although the substrate treatment had a final biomass of fish stored 12% higher than the substrate treatment, the growth of the periphytic biomass was able to maintain similar levels of nutrient concentration in both treatments (with and without substrates).
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Palavras-chave
Biomassa, Controle, Módulos de bambu, Qualidade da água, Tratamentos, Biomass, Control, Bamboo modules, Water quality, Treatments