Common snook (Centropomus undecimalis) is a relatively new species for aquaculture; considered as a recreational species and not commercial. The aim of this study was to develop common snook larval rearing techniques for stock enhancement. Common snook culture has two main bottlenecks, broodstock management and larval culture. High mortality during the first 6 days is the main limitation for successful larval survival. Broodstock management of common snook is still developing and the only source of common snook eggs is from wild broodstock. Securing a regular supply during the natural spawning was essential to reach the main objective. Finding the optimal spawning sites, as well as optimal spawning time was achieved. Results showed Terra Ceia, Longboat and Cayo Costa to be the best sites for wild broodstock collection. The onset of spawning was triggered by a rise in water temperature. During the 4 years of this study spawning started at the end of May and finished in September. Total capture results and egg quality results, such as fertilization, hatching rate and lipid analysis, indicated June and July as the peak months during the spawning season. Common snook follow a lunar spawning cycle. Results showed that one to three days after the new and full moon were the peak spawning periods and therefore the best days to capture wild stock. Common snook egg lipid composition fits the general marine fish fatty acid composition with saturated fatty acids predominating. On the other hand, the omega 3, omega 6 (n-3/n-6) ratio was lower than the typical marine fish and arachidonic acid values were significantly higher than other marine species. This egg fatty acid profile will be helpful in the future to compare it with captive spawned eggs for egg quality purposes. Description of the common snook embryonic and larval development for the first 14 days was carried out. This has strengthened knowledge for this species’ development, and should provide a helpful tool to identify common snook embryos and larvae in the wild. Novel improvements to existing common snook larval culture protocols were implemented. Larval lipid analysis throughout development, and high mortality around day 6 post hatching, suggested that common snook larvae were dying of starvation. Gross morphological development and ultra-structure findings in the digestive and eye system development during the first three days indicated that day 2 post hatching larvae were capable of capturing and digesting food. Additionally, larval nutritional improvements were made, increasing the larval survival. The most significant ones were: finding a smaller and more nutritional prey (SS type rotifers and copepods), finding an optimal stocking and feeding density and the importance that green water technique has on larval survival. Overall, larval success was improved from a zero percent survival during the first 14 days to a 2% survival rate.

Orientador: Carlos Raimundo Ferreira Grosso / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos / Made available in DSpace on 2018-08-05T13:49:57Z (GMT). No. of bitstreams: 1 Alvim_IzabelaDutra_D.pdf: 8886794 bytes, checksum: 16da2e8dd31802c6ce217aae14d9e70f (MD5) Previous issue date: 2005 / Resumo: A microencapsulação é uma técnica para recobrimento de substâncias para a proteção e/ou liberação controlada das mesmas. As microcápsulas podem ser uma alternativa para obtenção de uma dieta para alimentação das larvas de peixe na piscicultura intensiva. Dois métodos de microencapsulação foram empregados para produção de micropartículas, potenciais na substituição do alimento vivo (rotíferos e artêmias) oferecido às larvas de peixe nos primeiros estágios de desenvolvimento. O primeiro baseou-se na secagem em spray dryer de uma dieta líquida. Essa dieta desidratada sofreu aglomeração e recobrimento para manipulação do diâmetro médio das partículas e solubilidade. Os diâmetros médios dos aglomerados foram significativamente maiores que da dieta desidratada sem aglomeração. As solubilidades em sólidos solúveis e em proteínas solúveis da dieta sem recobrimento foram altas para 120 minutos de permanência em água. A adição de óleo à dieta desidratada e o recobrimento polimérico reduziu esses valores de solubilidade. O aspecto apresentado pela dieta desidratada sem recobrimento foi característico de produtos desidratados por spray dryer. Os aglomerados apresentaram camada de recobrimento com falhas, o que justificou as baixas diminuições de solubilidades observadas. O segundo processo de microencapsulação foi a coacervação complexa entre gelatina e goma arábica, e como recheios foram utilizados uma mistura de oleoresina de páprica e óleo de soja e dois compostos hidrofílicos (glicose ou isolado protéico de soro de leite) retidos em matrizes lipídicas sólidas. Por microscopias diversas (confocal, ótica e eletrônica de varredura) as micropartículas coacervadas se apresentaram esféricas e multinucleadas. As micropartículas coacervadas contendo oleoresina de páprica e óleo de soja foram reticuladas com glutaraldeído ou com transglutaminase, e submetidas à secagem por estufa com circulação de ar, liofilizador e spray dryer. A secagem em estufa não permitiu a obtenção de um material com micropartículas individualizadas enquanto a liofilização permitiu a manutenção da estrutura esférica para todas as amostras inclusive a sem reticulação. A secagem em spray dryer apresentou baixíssimo rendimento, e só foi possível para micropartículas reticuladas, com integridade das estruturas associada ao tipo/concentração de reticulante. A liberação da oleoresina foi avaliada em etanol absoluto por 120 minutos, para as micropartículas coacervadas úmidas com e sem reticulação e suas respectivas amostras desidratadas. A liberação do recheio foi alta (acima de 95%) para todas as amostras úmidas, exceto para a amostra reticulada com 1,0mM/g.ptn de glutaraldeído. As amostras desidratadas por liofilização tiveram liberação de seu conteúdo reduzida, não ultrapassando 35,4% após 120 minutos para todos os tratamentos. A liberação do recheio das micropartículas desidratadas por spray dryer foi baixa e proporcional a manutenção da integridade das partículas. Para veiculação dos compostos hidrofílicos nos coacervados, foram produzidas micropartículas lipídicas (spray chilling). Essas micropartículas lipídicas foram incorporadas com sucesso nos coacervados. A liberação dos compostos solúveis do interior dos coacervados foi maior para glicose que para a proteína, para 20 horas de permanência em água. A aceitação das micropartículas produzidas foi avaliada em um ensaio biológico in vivo com larvas de pacu. Foram testadas uma dieta aglomerada e quatro coacervados produzidos utilizando gelatina bovina ou gelatina de peixe na parede e óleo de soja ou gordura de peixe como recheio. O nível de aceitação das dietas foi de maiores valores para os coacervados produzidos com gelatina bovina/gordura de peixe e gelatina bovina/óleo de soja, seguidos pelo coacervado produzido com gelatina de peixe/óleo de soja, pelo aglomerado e por último o coacervado produzido com gelatina de peixe/gordura de peixe. Os coacervados produzidos com gelatina bovina contendo óleo de soja ou gordura de peixe apresentaram-se promissores como dietas necessitando ainda de ajustes nutricionais para atenderem as exigências das larvas em crescimento / Abstract: The microencapsulation is one technique for covering or evolving substances with the aim to provide protection and/or controlled release of the same ones. The microcapsules can be an alternative for attainment of a diet for feeding of the larvae of fish in the intensive aquaculture. Two methods of microencapsulation had been used for production of microparticles in the substitution of the alive food (rotifers and artemias) offered to the larvae of fish in the first periods of growing. The first one was based on the spray drying of one nutritionally and balanced liquid formulation. The dehydrated diet was agglomerated adjust the average size and solubility of the particles. The size of the agglomerated particles was increased efficiently. The solubilities in total soluble solids and soluble proteins of the diet without covering had been high with values (above 50%) for 120 minutes of permanence in water. The addition of oil to the dehydrated diet (OD) and the agglomation with pectate and calcium reduced the values of solubility. The aspect presented for the diet dehydrated without covering was characteristic of products dehydrated by spray dryer. The surface of the agglomerated particles presented some imperfections, which justified the low reductions of solubilities. The second process used was the complex coacervation between gelatin and acacia gum and as a core materials, a mixture of paprika oleoresin and vegetable soy oil and two hydrophilic composites (glucose or whey protein isolate). After, the lipidic microparticles were used as core material for microparticles obtained using complex coacervation. Using different types of microscopies (confocal, optical and scanning electronic microscopy) it was possible to characterize the coacervated microparticles that showed spherical geometry and multinuclear distribution of the core material. The microparticles containing paprika oleoresin of paprika and vegetable soy oil as core material had been crosslinked with glutaraldehyde or transglutaminase, and were dried using one oven with air circulation, spray dryer and freeze drying processes. The drying using oven did not allowed the attainment of a dry material presenting free flowing. The freeze drying, on the other side, allowed the attainment of microparticulated material showing spherical structure and free flowing for all samples including samples without cross-linking. The yield of the spray drying process was very low. This process did not work when non crosslinked samples were dried. The high level of cross-linking using 1.0mM/g of ptn showed the best results compared with transglutaminase or glutaraldehyde at 0.1mM/g of protein (reaction time of 18 hour for both) showing the maintenance of the moist microparticles structure. The release of the oleoresin was evaluated for the moist and dehydrated samples with and without crosslinking using ethanol as the release medium during 120 minutes. The core release observed was above 95% for moist coacervated without crosslinking, crosslinked using transglutaminase and for samples crosslinked with the low level of glutaraldehyde. The release level decreased when concentration of glutaraldehyde was increased. Dryed samples using freeze drying showed a great decrease on the release amount, not exceeding 35.4% after 120 minutes for all the treatments. The release of the core from the dehydrated microparticles using spray dryer was proportional to the maintenance of the integrity of particles. Again, cross-linking using high concentration of glutaraldehyde/g.ptn produced the best results.Lipídic microparticles had been incorporated successfully in the coacervated microparticles. The amount of released soluble composites using water solution was high to glucose and relative low for the protein after 20 hours of experiment. The acceptance of the microparticles was evaluated in a live biological assay using larvae of pacu. A diet agglomerated with calcium pectate and four coacervated microparticles using bovine gelatin or fish gelatin as the wall materials and vegetable soy oil or fat fish as core materials had been tested. Ranking of acceptance of the diets showed bigger values for the coacervated microparticles produced with gelatin/fat fish or gelatin/soy oil, followed by the microparticles produced with fish gelatin/soy oil, agglomerated particles and finally coacervate particles using fish gelatin/fat fish. The coacervation process showed interesting results but improvement on the nutritional balance needs to be done / Doutorado / Nutrição Experimental e Aplicada à Tecnologia de Alimentos / Doutor em Alimentos e Nutrição

Murray cod Maccullochella peelii peelii is an iconic freshwater angling species that has suffered declines in abundance and is now listed as a nationally vulnerable species. Despite recognition of the need for biological knowledge to provide future management directions, little is known of its ecology. This thesis examines that ecology to provide new knowledge and recommendations for improved conservation management. (For complete abstract open document)