• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 42
  • 9
  • 4
  • 2
  • 2
  • 1
  • 1
  • Tagged with
  • 77
  • 77
  • 28
  • 13
  • 11
  • 10
  • 9
  • 9
  • 9
  • 9
  • 8
  • 7
  • 6
  • 6
  • 6
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Relações corporais, composição centensimal e rendimento de filé do mandi (Pimelodus britskii), do Reservatório Salto Santiago - Rio Iguaçu / Coporate relations, centensimal composition and yield of filet of mandi (Pimelodus britskii) of Reservoir Salto Santiago - River Iguaçu

Almeida, Mara Cristina de 30 March 2010 (has links)
Made available in DSpace on 2017-07-10T17:48:20Z (GMT). No. of bitstreams: 1 Mara_Cristina_de_Almeida.pdf: 671208 bytes, checksum: 3d06bb753a794295c1d35ff900171c02 (MD5) Previous issue date: 2010-03-30 / The mandi-pintado (Pimelodus britskii) a endemic species from Iguaçu River basin seems to have high potential for commercial exploitation. Thus, the aim of this study was to evaluate the potential for commercial exploitation of the mandi (Pimelodus britskii) through analysis of body proportions, centesimal composition and fillet yield of fishes collected in the Salto Santiago reservoir. Catches occurred in May and July 2009 by longlines and gillnets distributed throughout the reservoir. After capture fishes were weighed, measured and sexed. They were divided into size classes (fish <150g, 150-300g fish and fish> 300g) Morphometric data (total length, standard length, head height, head length, trunk height and width), fillet yield, abdominal muscle, cleaned trunk without skin and centesimal composition were obtained. Differences between size classes were tested by one-factor ANOVA. Significant differences were found for height(16,48-26,29%) and width of the trunk(10,55-15,20%), length(27,5-38,06%) and width of the head(16,45-20,56%), fillet yield(37,26%), abdominal muscle(7,28%), cleaned trunk(50,09%), moisture(77,88%), lipids(13,33%) and ash(1%) among size classes. Overall Pimelodus britskii presented morphometric relationships, fillet yield and centesimal composition at levels comparable to other commercially exploited species, demonstrating that this species has high potential for commercial exploitation, either through fishing or farming / O mandi-pintado (Pimelodus britskii), uma espécie endêmica da bacia do rio Iguaçu parece apresentar elevado potencial para o aproveitamento comercial. Deste modo, o objetivo deste trabalho foi avaliar o potencial para o aproveitamento comercial do mandi (Pimelodus Britskii), através das análises das proporções corporais, composição centesimal e rendimento do filé, de peixes coletados no reservatório de Salto Santiago. As capturas ocorreram nos meses de maio e julho de 2009, através de espinhéis e redes de espera, distribuídos ao longo do reservatório. Após a captura, os peixes foram medidos, pesados e tiveram o sexo determinado. Foram divididos em classes de tamanhos (peixes <150g, peixes entre 150-300g e peixes >300g) Os dados morfométricos (comprimento total, comprimento padrão, altura da cabeça, comprimento da cabeça, altura do tronco e largura do tronco), rendimento de filé, músculo abdominal, tronco limpo sem pele e composição centesimal foram obtidos. As diferenças entre as classes de tamanho foram testadas através de ANOVA unifatorial. Foram verificadas diferenças significativas para altura (16,48-26,29%) e largura do tronco(10,55-15,20%), comprimento(27,5-38,06%) e largura da cabeça(16,45-20,56%), rendimento do filé(37,26%), músculo abdominal(7,28%), tronco limpo(50,09%), umidade(77,88%), lipídios(13,33%) e cinzas(1%) entre as classes de tamanho. De maneira geral Pimelodus britskii apresentou relações morfométricas, rendimento de filé e composição centesimal em niveis comparáveis aos de outras espécies exploradas comercialmente, demonstrando que esta espécie apresenta elevado potencial para a exploração comercial, seja através da pesca ou do cultivo
62

Engagement de la recherche agronomique dans l'action. Le cas d'une Recherche-Action en Partenariat au Cameroun / Commitment of agricultural research in action. The case of a Partnership Action-Research in Cameroon

Carbonnel, Anna 10 December 2012 (has links)
La Recherche-Action en Partenariat (R.A.P.) est une démarche de recherche conçue par des chercheurs du Centre de coopération Internationale en Recherche Agronomique pour le Développement (C.I.R.A.D.). D’après les concepteurs de la R.A.P., les inventions proposées par les chercheurs agronomes ne sont pas suffisamment prises en compte par les potentiels utilisateurs et ne se transforment pas forcément en innovation. Inspirée des sciences sociales et présentée comme une démarche capable d’élaborer des conditions favorables à la co-construction des innovations, la R.A.P. doit améliorer le passage entre l’invention des chercheurs et l’adoption de ces inventions par les utilisateurs. Cette thèse se focalise sur les conditions d’émergence de la R.A.P. au C.I.R.A.D. puis sur son application à deux terrains vivants : le Cameroun et le Burkina Faso. La question principale posée dans ce travail est de savoir si effectivement et concrètement,la R.A.P. s’inspire des sciences sociales pour favoriser la co-construction des innovations et atteindre l’un de ses objectifs : résoudre les problèmes des acteurs. Cette thèse est une réflexion sur la place et les actions possibles des sciences sociales en collaboration avec d’autres disciplines pour se mettre au service d’une telle démarche et de tels projets de développement. L’observation de la R.A.P. comme un objet de recherche socio-anthropologique donne à voir une multitude de questionnements essentiels tant pour le milieu de la recherche que pour les situations locales rencontrées. / Action Research in Partnership is an approach to research that was defined by researchers from the Centre International de Recherche Agronomique pour le Développement (C.I.R.A.D.), a French research center ‘working with developing countries to tackle international agricultural and development issues’. According to R.A.P. developers, the inventions submitted by agronomic researchers are not sufficiently taken into account by potential users and do not necessarily leadto innovation. Inspired by social sciences, and introduced as an approach capable of creating favourable conditions to enable a reciprocal commitment in innovation, R.A.P. must improve the transition between inventions by researchers and the adoption of these inventions by users. This thesis focuses on the conditions of the implementation of R.A.P. in C.I.R.A.D. and then on two countries: Cameroon and Burkina Faso. My main argument will essentially concentrate on determining, with a number of concrete examples, whether R.A.P. is indeed inspired by social sciences to encourage reciprocal commitment in innovation and attain one of its principal objectives, i.e. to resolve the problems faced by participants. This thesis examine the role and possible influences of social sciences in this type of approach and development projects. Theobservation of R.A.P. as an object of socio-anthropological research leads to a fundamental questioning, both in terms of research and in local geographical situations.
63

Variáveis reprodutivas do Surubim do Iguacu (Steindachneridion melanodermatum) e comparação do desenvolvimento do ontogenetico com o jundiá (Rhamdia quelen)

Sant´anna, João Felipe Moutinho 02 October 2009 (has links)
Made available in DSpace on 2017-07-21T19:59:48Z (GMT). No. of bitstreams: 1 Joao Felipe Moutinho.pdf: 1502053 bytes, checksum: 7b2e87ce68365a056bed078acc98f710 (MD5) Previous issue date: 2009-10-02 / Species of large size and commercial value are found in the basin of the Iguaçu, with the highlights, representatives of the order Siluriformes. The genus Steindachneridion belongs to the order Siluriformes and has restricted distribution of some rivers basins of South America. The endemic Iguaçu’s surubim (Steindachneridion melanodermatum) as well as other catfish, has characteristics that have attracted great interest for cultivation. Another representative of Siluriformes, with broad representation in the Iguaçu river, the jundiá (Rhamdia quelen), this species has already successfully introduced in commercial farming. The purpose of this study was to investigate the reproductive processes in the laboratory in order to define better strategies for induced spawning, fertilization rate and embryo-larval development of Siluriformes. The experiment was conducted in fishponds Station studied ichthyology Plant Ney Braga, located in the reservoir of Salto Segredo, PR. In order to evaluate qualitative and quantitative characteristics of semen surubim, S. melanodermatum, used the eleven males weighing between 1.1 and 2.4 kg were subjected to treatment hypophysation. The volume of semen collected from 0.4 to 2.5 mL. Sperm motility after collection has remained between 85 to 292 seconds when activated with water tank, and 66 and 268 seconds when activated with distilled water. For sperm concentration, we found values that ranged between 28 and 88 x106 sperm / mm ³. From 0 to 74 hours after fertilization, were performed on 37 samples every two hours for each species. Was observed organogenesis, hatching with closed mouth and anus, formation of the heart, eyes, fins and digestive tract. The larvae of S. melanodermatum and R. quelen have similar characteristics during development. / Espécies de grande porte e valor comercial são encontradas na bacia do Iguaçu, tendo como destaques, representantes da ordem Siluriforme. O gênero Steindachneridion pertence à ordem dos Siluriformes e possui distribuição restrita aos rios de algumas bacias da América do Sul. O endêmico surubim do Iguaçu (Steindachneridion melanodermatum), assim como outros siluriformes, apresenta características que vêm despertando grande interesse para o cultivo. Outro representante dos Siluriformes, com ampla representação no rio Iguaçu, é o jundiá (Rhamdia quelen), espécie esta já introduzida com sucesso na piscicultura comercial. O intuito deste trabalho foi de investigar os processos reprodutivos em laboratório a fim de definir melhores estratégias para reprodução induzida, taxa de fecundação, e desenvolvimento embrio-larval destes Siluriformes. O experimento foi realizado em viveiros de piscicultura da Estação de Estudos Ictiológicos da Usina Ney Braga, localizada na represa de Salto Segredo, PR. Com o objetivo de avaliar características qualitativas e quantitativas do sêmen de surubim, S. melanodermatum, utilizaram-se onze machos com peso entre 1,1 e 2,4 kg, submetidos ao tratamento de hipofisação. O volume de sêmen coletado variou de 0,4 a 2,5 mL. A motilidade dos espermatozóides após a coleta manteve-se entre 85 a 292 segundos, quando ativados com água do tanque, e de 66 e 268 segundos, quando ativados com água destilada. Para a concentração espermática, foram encontrados valores que oscilaram entre 28 e 88 x106 espermatozóides/mm³. Entre 0 à 74 horas pós fertilização, foram realizadas 37 coletas à cada duas horas, para cada espécie. Foi observada a organogênese, eclosão com boca e ânus fechados, formação do coração, olhos, nadadeiras e trato digestório. As larvas de S. melanodermatum e R. quelen possuem características similares durante o desenvolvimento.
64

Tratamento de efluente da piscicultura utilizando os processos fenton e eletroquímico: eficiência e toxicidade / Effluent treatament of pisciculture using the fenton and electrochemical processes: efficiency and toxicity

Gomes , Lúcio de Moura 27 October 2016 (has links)
Fish farming is an important process of food production that seeks to meet the population growth, however is a source of pollution generating large volumes of contaminated water, causing environmental pollution. In order to minimize this impact, this study aimed to evaluate the efficiency of two advanced oxidative techniques to treat real effluent from fish farming, the Fenton reaction and electrochemistry. Treatments were carry out on a pilot scale (60L) and laboratory scale (250 mL). The efficiency of the reactions was assessed by the reduction of turbidity and COD of the effluent, as well as the toxicity of the effluent after treatment in germination lettuce (Lactura sativa) and mortality and sensory performance of the Nile tilapia (Oreochromis niloticus). For the Fenton reaction, it assessed the influence of the concentration of Fenton reagent (Fe2+ and H2O2), and the electrochemical process evaluated the applied current density and the supporting electrolyte (Na2SO4, H2SO4 and NaCl). According to the results of the physicochemical analyzes, both technologies were also effective in the treatment of this effluent, with reductions of 99% and 95% of the turbidity and COD respectively, for the Fenton reaction followed by flocculation; and 95% to 89% in turbidity and COD respectively, for the electrochemical process. In the electrochemical process the efficiency was associated with direct and indirect oxidation of pollutants and flotation of the particulate material through electrogenerated gas. In toxicological test of Fenton reagent with lettuce seeds, the Fe2+ concentrations showed no toxicity, since the H2O2 concentrations indicated high toxicity. Tests with Nile tilapia corroborate the results of lettuce seeds. After the treatment with Fenton's reaction effluent treated with 10 mmol of H2O2 L-1 and 0.5 mmol Fe2+ had the same germination and root growth rates of the raw wastewater, as in the tests with Nile tilapia effluent showed considerable toxicity, possibly due to residual peroxide. In the electrochemical process the best results were obtained when employed the H2SO4 as supporting electrolyte and the lowest current density (10 mA cm-2). The toxicology tests with lettuce and Nile tilapia indicated that the treated effluent has low toxicity with germination rate and lettuce radicle growth equal to control, and Nile tilapia the mortality rate was zero, even after 96 hours of fish contact with the treated effluent. The techniques applied in this study showed high efficiency in the treatment of real effluent from fish farming, making it adequate for disposal or reutilization. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A piscicultura é um importante processo de produção de alimentos que busca atender o crescimento populacional, porém pode ser uma fonte poluidora, gerando grandes volumes de água contaminada, causando poluição ambiental. Visando minimizar esse impacto, esse trabalho teve como objetivo avaliar a eficiência de dois processos oxidativas avançadas no tratamento de efluente real gerado pela piscicultura, a reação de Fenton e a eletroquímica. Os tratamentos foram realizados em escalas, piloto (60 L) e de bancada (250 mL). A eficiência das reações foi avaliada pela redução da turbidez e DQO (Demanda Química de Oxigênio) do efluente, bem como a toxicidade do efluente após o tratamento frente à germinação da alface (Lactura sativa) e mortandade e comportamento sensorial da tilápia do Nilo (Oreochromis niloticus). Para a reação de Fenton, avaliou-se a influência da concentração dos seus reagentes (Fe2+ e H2O2), e para o processo eletroquímico avaliou-se a densidade de corrente aplicada e o eletrólito suporte (Na2SO4, H2SO4 e NaCl). De acordo com os resultados das análises físico-químicas, os dois processos apresentaram alta eficiência no tratamento deste efluente, com reduções de 99% (turbidez) e 95% (DQO), para a reação de Fenton seguida de floculação, e para o processo eletroquímico as reduções foram de 95% (turbidez) e 89% (DQO). No processo eletroquímico a eficiência foi associada à oxidação direta e indireta dos poluentes e flotação do material particulado através dos gases eletrogerados. Nos ensaios toxicológicos dos reagentes de Fenton com sementes da alface, as concentrações de Fe+2 não apresentaram toxicidade, já as concentrações de H2O2 indicaram elevado grau toxicológico. Os ensaios com tilápia do Nilo corroboraram com os resultados das sementes da alface. Após o tratamento com reação de Fenton o efluente tratado com 10 mmol L-1 de H2O2 e 0,5 mmol de Fe2+ apresentou os mesmos índices de germinação e crescimento da radícula do efluente bruto, já nos testes com tilápia do Nilo o efluente apresentou considerável toxicidade, possivelmente devido a peróxido residual. No processo eletroquímico os melhores resultados foram obtidos quando empregado H2SO4 como eletrólito suporte e a menor densidade de corrente (10 mA cm-2). Os testes toxicológicos com alface e tilápia do Nilo indicaram que o efluente tratado apresenta baixa toxicidade com índice de germinação e de crescimento da radícula da alface igual a do controle, e com tilápia do Nilo o índice de mortandade foi nulo, mesmo após 96h de contato dos peixes com o efluente tratado. As técnicas aplicadas neste estudo apresentaram alta eficácia no tratamento do efluente real da piscicultura, tornando-o adequado para descarte ou mesmo reutilizado em sistema de ciclo fechado.
65

Alimentos convencionais e não-convencionais na engorda e qualidade de pescado do jundiá(Rhamdia quelen) / Conventional and alternative feedstuffs on growth and flesh quality of jundiá (Rhamdia quelen)

Veiverberg, Cátia Aline 09 December 2011 (has links)
Conselho Nacional de Desenvolvimento Científico e Tecnológico / Die to rapid growth of aquaculture and the consequent increase for aquaculture feed, the industry's main challenge is to identify potential dietary ingredients that ensure satisfactory performance, economic viability and quality of fish. Considering this demand, the aim of this study was to evaluate the combination of different protein sources on feeding of jundiá juvenile, and their effects on growth, metabolism and quality of fish. Three experiments were conducted. In experiment 1, diets containing alternative protein sources in combination with soybean meal were evaluated: PMM: porcine meat meal; CM: canola meal; SFM: sunflower meal; PBM: poultry by-product meal. After 12 experimental weeks, jundiá fed diets PMM and PBM showed greater weight gain and better feed conversion than those fed diets with plant-protein diets. The enzyme activity, intestinal quotient and somatic indices changed according to the dietary protein source. Fish fed diets PMM and PBM had higher concentrations of plasma triglycerides and cholesterol, and higher fat content in fillet and whole fish, reflecting the higher fat diets. Fish fed diets CM and SFM had lower protein deposition. In the second experiment, the aim was to evaluate the effect of supplementation strategies for limiting amino acids in the diet of jundiá on growth, metabolic response and possible impact on fillet quality. The experimental diets were: CON: porcine meat meal + soybean meal, supplemented with lysine and methionine; MIX: mixture of plant and animal-protein sources, without supplementation of synthetic amino acids; VEG: mixture of plant-protein meals and supplementation with lysine and methionine. At the end of eight weeks trial, there were no significant differences on the performance and fillet composition. However, there were changes in metabolic response of jundiá die to diet composition, which was reflected in body fat content. The VEG diet altered the color and brightness of fillets, although these differences were not detected in the sensory analysis. The third experiment was conducted to evaluate the apparent digestibility coefficients (ADC) of dry matter, organic matter, crude protein, gross energy and fat of the following ingredients: canola meal, porcine meat meal, sunflower meal, soybean meal and poultry by-product meal. Feces were collected in modified Guelph system, using chromium oxide (0.2% in diet) as marker. From the ADC of diets were estimated ADC of ingredients. Porcine meat meal showed the worst digestibility coefficients for all nutritional fractions (about 30%), whereas plant-protein sources showed good digestibility coefficients (between 70 and 80%). Based on the results obtained in this work, we can conclude that: canola meal or sunflower meal in combination with soybean meal in large quantities are not an alternative dietary protein to jundiá; The combination of three plant protein meals, included in small amounts in the diet can provide similar weight gain to that obtained with the CON diet; There is no need for supplementation of free amino acids in diets composed by the combination of vegetable and animal meals in small proportions. / Com o crescimento acelerado da aquicultura e consequente aumento da demanda por rações aquícolas, o principal desafio da indústria consiste em identificar ingredientes potenciais para inclusão nas dietas, que garantam desempenho satisfatório, viabilidade econômica e qualidade do pescado. Considerando esta demanda, o objetivo deste trabalho foi avaliar a combinação de fontes proteicas de origem animal e vegetal na alimentação de juvenis de jundiá, e seus efeitos sobre o crescimento, metabolismo e a qualidade do pescado. Foram conduzidos três experimentos, dois de crescimento e um de digestibilidade. No experimento 1, foram avaliadas dietas contendo fontes proteicas alternativas em combinação com farelo de soja: FCS: farinha de carne suína; FCN: farelo de canola; FGI: farelo de girassol; FVA: farinha de vísceras de aves. Ao final de 12 semanas, os jundiás alimentados com as dietas FCS e FVA apresentaram maior ganho em peso e melhor conversão alimentar que os alimentados com as dietas vegetais. A atividade enzimática, o quociente intestinal e os índices hepato e digestivo-somático foram alterados em função da fonte proteica da dieta. Os peixes alimentados com as dietas FCS e FVA apresentaram maior concentração de triglicerídeos e colesterol plasmáticos, além de maior percentual de gordura no filé e no peixe inteiro, como reflexo do maior teor de gordura nas dietas. Os peixes alimentados com as dietas FCN e FGI apresentaram menor taxa de deposição de proteína corporal e no filé. No segundo experimento, o objetivo foi avaliar o efeito de estratégias de suplementação de aminoácidos limitantes na dieta de jundiás sobre o desempenho zootécnico, resposta metabólica e possíveis reflexos na qualidade dos filés. As dietas avaliadas foram: CON: farinha de carne suína+farelo de soja+suplementação com lisina e metionina; MIX: mistura de farelos vegetais e farinhas animais sem suplementação de aminoácidos livres; VEG: mistura de farelos vegetais e suplementação com lisina e metionina. Ao final de oito semanas, não foram observadas diferenças significativas no desempenho zootécnico e composição dos filés nos diferentes tratamentos. Entretanto, houve alteração da resposta metabólica dos jundiás em função da composição da dieta, que se refletiu no teor de gordura corporal. A dieta VEG alterou a cor e a luminosidade dos filés de jundiá. Entretanto, estas diferenças não foram detectadas na análise sensorial. O terceiro experimento foi realizado para avaliar os coeficientes de digestibilidade aparente (CDA) da matéria seca, matéria orgânica, proteína bruta, energia bruta e gordura dos seguintes ingredientes: farelo de canola, farinha de carne suína, farelo de girassol, farelo de soja e farinha de aves. As fezes foram coletadas em sistema de Guelph modificado, utilizando óxido de cromo (0,2% na dieta). A partir dos CDA das dietas foram estimados os CDA dos ingredientes. A farinha de carne suína apresentou os piores coeficientes de digestibilidade para todas as frações nutricionais (em torno de 30%), enquanto que as fontes proteicas vegetais apresentaram bons coeficientes de digestibilidade (entre 70 e 80%). Com base nos resultados obtidos, pode-se concluir que: Os farelos de canola ou de girassol em combinação com o farelo de soja, em grandes quantidades, não se apresentam como alternativa proteica na dieta de jundiás na fase de recria/engorda; A combinação de farelos vegetais, incluídos em pequenas quantidades na dieta, é capaz de proporcionar ganho em peso semelhante ao obtido com a dieta controle; Não há necessidade de suplementação de aminoácidos livres em dietas compostas pela combinação de farelos vegetais e farinhas animais em pequenas proporções.
66

Cultivo de surubim pintado (Pseudoplatystoma corruscans) e híbrido (P. reticulatum X P. corruscans) em sistema de recirculação de água

Miranda, Mário Olindo Tallarico de 31 May 2012 (has links)
Made available in DSpace on 2016-06-02T19:29:53Z (GMT). No. of bitstreams: 1 4560.pdf: 1880275 bytes, checksum: 259fd9d9b3aeb99130c54c0ee0f5af82 (MD5) Previous issue date: 2012-05-31 / This study aimed to test a pilot recirculating aquaculture system (RAS) and to evaluate in this system the effects of the stocking density on the production of species of surubim pintado , Pseudoplatystoma corruscans, and its hybrid with P. reticulatum regarding the effect of stocking density and water renewal rate on the hybrid production. The study lasted for 84 days. The physical and chemical conditions in the RAS was evaluated by measuring water consumption (223,6 L/kg of fish produced), temperature (25,8±0,7ºC), dissolved oxygen (5,33±0,04 mg/L O2 in the water inlet to culture tanks), pH (6,75±0,25), total alkalinity (40,0±20,6 mg/L CaCO3), carbon dioxide (16,6±6,1 mg/L CO2), total suspended solids (8,0±4,2 mg/L TSS), total ammonia nitrogen (0,18±0,10 mg/L NH3-N), nitrite (0,163±0,090 mg/L NO2-) and nitrate (58,0±9,7 mg/L NO3-). To evaluate the fish performance, two experiments were conducted simultaneously. In experiment 1, densities of 40, 80 and 120 fish.m-3 (approximately 8.5, 17 and 25.5 kg.m-3) for the pure and the hybrid lineages were tested using a 3 x 2 factorial design (three densities and two lineages). In experiment 2, only the hybrid lineage was used, and three stocking densities were tested: 20, 40 and 60 fish.m-3 (approximately 9, 18 and 27 kg.m-3) and two water renewal rates (1 L/kg.min-1 and 0,5 L/kg.min-1), using a 3 x 2 factorial design (three densities and two water renewal rates). Fish were fed with extruded food (40% crude protein) at a rate of 2.5% of the body weight per day. For both experiments, daily specific growth rate (SGR), final weight, biomass gain, final density, food conversion, final weight and dissolved oxygen levels at the tank outlet are discussed. In experiment 1, both lineages showed to be adapted to the RAS, but the hybrid lineage had a better performance than the pure lineage. In experiment 2, the highest water renewal rate resulted in a better performance, and an increase in density improved the final production. / O objetivo deste trabalho foi testar um sistema piloto de recirculação de água (SRA) e avaliar neste sistema o efeito da densidade de estocagem no cultivo de surubins puros, Pseudoplatystoma corruscans, e do seu híbrido (P. reticulatum x P. corruscans) e o efeito da densidade de estocagem e da taxa de renovação de água no cultivo do híbrido. O trabalho teve duração de 84 dias. O SRA foi avaliado através das medições de consumo de água (223,6 L/kg de peixe produzido), temperatura (25,8±0,7ºC), oxigênio dissolvido (5,33±0,04 mg/L de O2 na água de abastecimento dos tanques de cultivo), pH (6,75±0,25), alcalinidade total (40,0±20,6 mg/L CaCO3), gás carbônico (16,6±6,1 mg/L CO2), sólidos suspensos totais (8,0±4,2 mg/L SST), nitrogênio amoniacal total (0,18±0,10 mg/L NH3-N), nitrito (0,163±0,090 mg/L NO2-) e nitrato (58,0±9,7 mg/L NO3-). Para avaliação do desempenho dos peixes, foram realizados dois experimentos simultaneamente. No experimento 1 foram testadas as densidades de 40, 80 e 120 peixes/m3 (aproximadamente 8,5, 17 e 25,5 Kg/m³) para as linhagens pura e híbrida, num delineamento em fatorial 3 × 2 (três densidades e duas linhagens). No experimento 2 foi utilizada somente a linhagem híbrida, tendo sido testadas 3 densidades de estocagem, 20, 40 e 60 peixes/m3 (aproximadamente 9, 18 e 27 Kg/m³) e duas taxas de renovação de água (1 L/kg.min-1 e 0,5 L/kg.min-1), num delineamento em fatorial 3 × 2 (três densidades de estocagem e duas taxas de renovação de água). A alimentação dos peixes nos dois experimentos foi realizada com ração extrusada (40% de proteína bruta) na proporção de 2,5% da biomassa, ministrada diariamente. Para os dois experimentos foram discutidos dados de taxa de crescimento específico diária, peso final, ganho de biomassa, densidade final produzida, conversão alimentar, peso final e níveis de oxigênio dissolvido na saída dos tanques. No experimento 1, foi observado que as duas linhagens se adaptaram ao SRA, porém a linhagem híbrida teve melhor desempenho que a linhagem pura. No experimento 2, a maior taxa de renovação de água proporcionou melhor desempenho e o aumento de densidade, incrementando a produção final.
67

AvaliaÃÃo dos Riscos Ambientais e EcotoxicolÃgicos do ReÃso de Ãguas ResiduÃrias em Piscicultura / Evaluation of Environmental and Ecotoxicological Risks of Wastewater Reuse for Fish Farming

Soraia Tavares de Souza Gradvohl 14 August 2006 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / A preocupaÃÃo com relaÃÃo à qualidade e à quantidade de Ãgua potÃvel tem incentivado o reÃso de Ãgua como uma das alternativas para enfrentar este problema. O reÃso tornou-se, portanto, um importante instrumento de gestÃo ambiental, visando à liberaÃÃo da Ãgua de melhor qualidade para fins mais nobres. O reÃso com aplicaÃÃo na piscicultura constitui fonte alternativa de produÃÃo de proteÃna a baixo custo, alÃm de funcionar como uma forma de reciclagem de nutrientes. Mas, a sustentabilidade desta atividade està diretamente relacionada à qualidade do efluente tratado e seus efeitos sobre a qualidade da Ãgua nos tanques de peixes. Outro fato notÃrio à a crescente preocupaÃÃo com os riscos potenciais inerentes a esta atividade. Diante deste cenÃrio, surgiu a necessidade de realizar um estudo mais profundo dos riscos inerentes ao reÃso de Ãguas residuÃrias, tanto numa abordagem ambiental, como num ponto de vista ecotoxicolÃgico. Para isso, foram realizados testes de toxicidade aguda, de curta duraÃÃo, para avaliaÃÃo da toxicidade dos efluentes tratado e bruto provenientes de uma EstaÃÃo de Tratamento de Esgoto a nÃvel terciÃrio, composto por um sistema de lagoas de estabilizaÃÃo, tendo como organismos-teste peixes de Ãgua doce da espÃcie Oreochromis niloticus (tilÃpia do Nilo). Os testes objetivaram determinar o Ãndice de toxicidade aguda (LC50). O efluente tratado foi utilizado em duas etapas distintas, com peixes com idade superior a 60 dias e alevinos com tempo de vida inferior a 15 dias. Em ambos, nÃo foi observada mortalidade de nenhum organismo. No caso do esgoto bruto, o ensaio foi realizado com e sem aeraÃÃo, sendo obtido para o esgoto bruto sem aeraÃÃo os Ãndices de LC50-24h de 68,0% e LC50-96h de 35,4%. Jà com a aeraÃÃo mecÃnica aplicada Ãs duas diluiÃÃes de 50 e 100% de esgoto bruto, os LC50âs encontrados foram de 44,5% (24 h), 41,0% (48 h) e 36,7% (96 h). O ensaio foi tambÃm realizado para avaliaÃÃo do nÃvel de toxicidade da amÃnia, tendo em vista que a mesma tem sido considerada por vÃrios pesquisadores um produto tÃxico Ãs algas, ao zooplÃncton e aos peixes. Para estes ensaios foram determinados os LC50âs de 2,01 mg/L NH3-N (2 h), 1,97 mg/L NH3-N (4 h) e 1,66 mg/L NH3-N (atà 96 h). AlÃm disso, foi realizado um ensaio com nitrogÃnio amoniacal variando-se o pH para originar trÃs meios distintos â Ãcido, neutro e bÃsico â devido a influÃncia deste no Ãndice de toxicidade calculado. Os LC50âs encontrados neste caso foram: 8,70 mg/L para o tempo de 2 a 4 horas e 6,45 mg/L para 24, 48 e 96 horas para o meio Ãcido; 8,70 mg/L para 2 horas e 6,45 mg/L para 4, 24, 48 e 96 horas para o meio neutro; e, 1,96 mg/L de 2 horas em diante para o meio bÃsico. Por fim, foi utilizada uma metodologia de anÃlise de riscos buscando-se realizar um estudo dos efeitos potenciais à saÃde humana e ao meio ambiente, e ainda propondo-se medidas para tentar minimizar os possÃveis impactos adversos.
68

Beyond the Surface : Bringing attention to the origin of food with the fish finger as canvas

Benevides, Lara January 2017 (has links)
The many technological processes that products go through can make consumers less related to the systems behind them and their origins. The same thing happens to food. This project highlights the implications of a food system within the global scale of today’s mainstream economy and explores the possibilities for a product that originates from a more sustainable food system. Apart from re-designing a processed everyday food product, the aim of this study is to increase awareness of the pressure that the world’s fish stocks are suffering due to overfishing – an issue that is being aggravated by our current food system. For this reason fish fingers (aka fish sticks), which is a well known food product in Sweden, have been chosen as the primary focus in order to make a complex issue more tangible. By re-evaluating what a fish is, analysing current food systems and food products, making sensory explorations and collaborating with chefs, Havsbitar 1.0 and 2.0 (”Sea Bites” 1.0 and 2.0) have been developed. It is a series of fish fingers that has been designed for a desirable future scenario, where a resilient food system has been implemented. The aesthetics of Havsbitar intends to connect it to its ingredients and to the ecosystem it comes from, while maintaining the key characteristics of the fish finger as we know it today. The acceptance of the concept as a food product is an important variable to this project. The concept is placed in the field of Transition Design. Nevertheless, the design of Havsbitar 1.0 is a proposal that is intended to create possibilities for dialogue about an ideal industrialized commercial product. On the other hand, Havsbitar 2.0 follows a more discursive, critical angle towards the fact that fish fingers do not resemble fish, its main ingredient. Havsbitar 2.0 could then be placed in the field of Critical Food Design and Discursive Design.
69

The Farm : A new urban condition

Arvidsson, Jesper January 2012 (has links)
The Farm is a speculative proposal for a self sustainable city block where as much food is produces as is consumed by it’s inhabitants. It is utilising the potential that arise when the greenery of farming is brought in to the cities in creating a new hybrid that blends with the city fabric with the aim of contributing to the areas multiplicity and vibrant life. The aim of the project has been that through architecture design; study the possibility to go from a throughput society, where everything we consume is produced outside of the community, to a society that produces what it consumes within the community in a cyclical integrated sustainable way. Can we produce what we consume with in a city and what happens when the production, which in this case is the cultivation of crops and plants, merge with the existing city fabric? What happens if the cultivation is combined with a traditional apartment program and what does it  become? Can the programs thrive together in symbiosis or will one of the programs become a parasite of the other? How does the vast open spaces required for farming relate to the small intimate spaces suitable for living spaces? What is their interrelationship, how do they effect each other?
70

Development potential and financial viability of fish farming in Ghana

Asmah, Ruby January 2008 (has links)
The potential for aquaculture development to make up for an annual 400,000mt shortfall in domestic fish supply was investigated. This involved an overview of the sector to determine its trends and operations and identifying strengths and constraints, a financial viability assessment of the sector, based on mode and levels of operation of existing farms, an assessment of the market and trade for cultured fish with a focus on Oreochromis niloticus, and finally, a GIS approach to update and reassess the potential for aquaculture development in Ghana. Data were obtained from both primary and secondary sources, the former, via fish farmer, dealers and consumer questionnaire surveys. Results of the study showed that interests in fish farming continue to grow with an overall annual average growth rate of 16% since 2000. The existing farms, 1300 in number were however very small with a mean farm size of 0.36ha and a median 0.06ha of which commercial farms accounted for less than 3%. Based on sizes, mode of operation and levels of input and output, five subsistence farm types were identified. Mean production from these pond-based farms ranged from 1436kg/ha/yr- to 4,423kg/ha/yr while that of a medium sized intensive commercial pond farm was 45,999kg/ha/yr. Commercial farming accounted for about 75% of 2006 aquaculture production. The main strength identified was the growing interest in both commercial and non-commercial fish farming and the main constraints were lack of quality seed, low levels of technical support and of knowledge in fish farming practices among non-commercial farmers. Net profits of commercial farms ranged from GH¢ 3,341 (US$3480)/ha/yr to GH¢ 51,444 (US$ 53,587)/ha/yr with payback from 1 to 4yrs, IRR at 35% to 105% and NPV from GH¢ 5,898 to GH¢ 236,412. By contrast, only two of the five non-commercial farm types made positive net returns ranging, from GH¢158 to GH¢1100/ha/yr, with minimum payback period of 14yrs, NPVs of less than 1 and the best IRR being just 4%, when initial capital requirements are full costed. Uncosted family labour inputs and negligible land opportunity costs improved viabilities for two farm types, where net returns/ha/yr increased by more than 50%, minimum payback dropped to 2 years, NPV from GH¢ 4839 to GH¢ 9330 and minimum IRR of 45%. Main constraints identified as affecting the profitability of subsistence farming were the relatively low prices of fish and the low levels of output which could be improved through better farming practices. From the market survey, a huge market potential for tilapia was identified with a current supply deficit of 41,000mt. The most preferred sizes by consumers and with potentially good market price for traders were those weighing at least 200g. For dealers, trading in cultured fish was found to be more profitable than trading wild capture tilapia because of lower wholesaler prices, gross profit margins were GH¢ 0.49/kg and GH¢ 0.25/kg respectively. Preference for tilapia was influenced by taste, availability, and its perceived health benefit. A key constraint to the sector was poor post-harvest handling and preservation of the fish resulting in shorter shelf life. From the GIS study, 2% (3,692 km2) of available land area was identified as very suitable for subsistence and about 0.2% (313.8km2) for commercial farming. A further 97.4% and 84.0% were identified as suitable for subsistence and commercial farming respectively. Areas with potential for cage culture were also identified, which were largely in the southern and mid-sections of the country. The overall conclusions are that based on natural resource requirements, market potential and financial viability, Ghana has the potential to totally make up the shortfall in domestic fish supply through aquaculture production. The current 400,000mt shortfall in domestic fish production can be achieved by 2020 by increasing overall aquaculture production by 60% per annum.

Page generated in 0.4635 seconds