During preliminary research on cobia (Rachycentron canadum, L.) it became increasingly clear that more in-depth information was required to provide enabling techniques for the cobia aquaculture industry to develop more rapidly. A unifying theme in many of the more important issues facing cobia aquaculture is nutrition. This led to nutritional investigations with larval and juvenile fish highlighting the impacts of dietary ingredients on animal performance. Indeed, nutrition can be viewed as a central lever of action through which many aspects of the physiology and the environmental (water) quality of the animal can be controlled. The first project focused on studying the larval development of cobia, a fish species highly suitable for aquaculture for which the industry is nascent. I described the time-course of development of external sensory organs, gut morphology and relevant digestive enzymes under controlled conditions using electron microscopy, histology and spectrophotometric assays. The developmental sequence of larval cobia could be separated in two phases, with a transition period between 12 and 14 days post hatch (dph). This transition is characterized by the formation of the intestinal loop, the establishment of basic cranial neuromast configuration, leading to the initiation of the onset of pancreatic enzymes and the increase of growth rate. In addition, the effects of dietary taurine supplementation and incorporation of mannan oligosaccharides (MOS) into live feeds on cobia larvae development was examined. Fish fed supplementary MOS did not grow faster but displayed higher microvilli length and density. In addition, MOS-fed fish were more resistant to salinity stress. The dietary supplementation of taurine resulted in a dramatic increase in survival, growth and development rates, and enzymatic activities. The second project aimed at refining cobia juvenile nutrition, assessing fish meal and fish oil replacements. Novel sources, including soy protein and oil, were investigated with and without amino acid and MOS supplementations, yielding promising results. Indeed, both fish meal and fish oil were replaced completely and successfully in feeds for juvenile cobia. In addition, novel ingredients (e.g. marine algae meals and soy protein concentrate) were identified to effectively achieve such replacement. The third and last project dealt with nutrient-gene interactions, specifically centering attention on immunostimulants for which the underlying mechanisms of action remain poorly characterized. Here, dietary MOS, nucleotides and selenomethionine (Se-met) were offered to zebrafish whose transcriptome was analyzed by microarray. The immune system, humoral or cellular, innate or adaptive, exhibited different patterns of response according to the immunostimulating nutrient used. In addition, various genes involved in cell cycle and cytokinesis were concomitantly expressed. An intriguing observation related to the insulinomimetic effect of Se-met. In other words, Se-met impacted pathways normally regulated by insulin, such as the MAPK and PI3K pathways. Some Insulin-like Growth Factors (IGF) and IGF bindgin proteins were up-regulated. Additional research is however necessary prior to advocating for the use of these additives, in order to further investigate their respective pros and cons. / Ph. D.

Cobia (Rachycentron canadum) is a tropical marine fish, with increasing commercial aquaculture importance worldwide. One of the major limitations to intensive aquaculture is disease. Diseases spread rapidly in an aquatic environment and pose a major threat to the development and introduction of new species, such as cobia, in aquaculture. This is due to the necessity to use wild caught broodstock, which pose a greater threat to introducing disease to a facility. Bacteria of the genus Vibrio play a major role in the diseases of cultured cobia and other species of marine fish. The goal of this study is to reduce the incidence of disease in a population, by either eliminating the potential pathogen or increasing the resistance of the host. To reach that goal, a disinfection assay to evaluate the effectiveness of nine common aquaculture chemical disinfecting compounds was evaluated against two bacterial pathogens (Vibrio anguillarum and V. ordalii). Both bacterial species were susceptible to a variety of common disinfecting compounds including Chloramine-T®, chlorine, ethanol, iodine, Lysol®, Roccal®-D Plus, and Virkon-S®. In addition, both species showed a resistance to disinfection with formalin and tap water. The humoral immune response of cobia to vaccination with a commercially-available vaccine for Vibrio spp. was evaluated by an ELISA. There was a significant difference between control and vaccinated groups (P<0.0001), showing significant antibody production resulting from vaccination. / Master of Science

Submitted by (edna.saturno@ufrpe.br) on 2017-02-22T16:32:41Z No. of bitstreams: 1 Victor Andrade da Silva.pdf: 390078 bytes, checksum: c2381631004f76239866e7fbd989d9a9 (MD5) / Made available in DSpace on 2017-02-22T16:32:41Z (GMT). No. of bitstreams: 1 Victor Andrade da Silva.pdf: 390078 bytes, checksum: c2381631004f76239866e7fbd989d9a9 (MD5) Previous issue date: 2013-02-27 / Stocking density is recognized as a critical factor in aquaculture, since high densities represent a potential source of chronic stress. This study investigated the effects of a chronic stressor, such as high stocking densities, on growth, physiological responses, and flesh quality of juvenile cobia (Rachycentron canadum) tested for a period of 42 days. The trial was conducted in a recirculating aquaculture system equipped with tanks of 70 L tanks. Cobia of 46.32 ± 0.22 g (mean ± SEM) were randomly distributed into three stocking densities (3.30 ± 0.02; 6.67 ± 0.03; 13.15 ± 0.16 g L-1), and three replicates. Treatment groups were nominally assigned as low density (LD; 5 fish/tank), medium density (MD; 10 fish/tank), and high density (HD; 20 fish/tank), respectively. Plasma concentrations of cortisol, osmolality and lactate were not affected by density levels, and values were according with those reported as basal for juvenile cobia. However, growth rate were influenced by density levels, in which weight gain and specific growth rate were significantly higher in the LD group. Drip loss did not differ among density groups. However, stocking density influenced the onset and development of rigor mortis. Our findings indicated that rearing juvenile cobia at the high densities negatively affected growth rate and flesh quality. Results suggest that juvenile cobia reared at the high densities were able to counteract stress. However, energy from the diet and/or body reserves was diverted from growth as a response to the elevated metabolic demand caused by stress. In this regard, juvenile cobia should be maintained at a final biomass up to approximately 15 kg m-3 to ensure a maximal growth rate and an improved final product quality. To our knowledge, this is the first report assessing the influence of a chronic stressor on both physiological responses and flesh quality parameters in cobia. This may provide information to the advancement of cobia aquaculture, leading to improvements in fish welfare, final product quality and increased productivity. / A densidade de estocagem é amplamente reconhecida como um fator crítico em aquicultura, uma vez que altas densidades representam uma potencial fonte de estresse crônico. Este estudo avaliou a resposta fisiológica, desempenho zootécnico e qualidade de filé de juvenis de beijupirá (Rachycentron canadum) submetidos a um estressor crônico, como altas densidades, visando à definição de condições de criação que levem à melhoria do bem estar animal e ao incremento da produtividade e qualidade do produto final. Os peixes foram testados por um período de 42 dias, em que juvenis de 46,32 ± 0,22 g (média ± erro padrão) foram aleatoriamente distribuídos em três densidades (3,30 ± 0,02; 6,67 ± 0,03; 13,15 ± 0,16 g L-1), e em três repetições. Os tratamentos foram designados como baixa densidade (LD; 5 peixe/tanque), densidade média (MD; 10 peixe/tanque), e alta densidade (HD; 20 peixes/tanque), respectivamente. As concentrações de cortisol e lactato e a osmolalidade do plasma sanguíneo não foram afetadas pela densidade de estocagem, e seus valores estavam de acordo com as faixas basais previamente relatados para juvenis de beijupirá. No entanto, o ganho de peso e a taxa de crescimento específico foram significativamente maiores no grupo LD. A densidade de estocagem também influenciou o início e o desenvolvimento do rigor mortis. Juvenis de beijupirá criados na alta densidade apresentaram menor taxa de crescimento e qualidade de filé. Os resultados sugerem que juvenis de beijupirá criados nas altas densidades foram capazes de contrapor o estresse ao nível de composição do plasma. Contudo, energia da dieta e/ou reservas do corpo podem ter sido desviadas do crescimento como resposta à alta demanda metabólica causada pelo estresse. Dessa forma, o presente estudo sugere que juvenis de beijupirá devem ser mantidos em uma biomassa final de até 15 kg m-3, aproximadamente para garantir máximo crescimento e melhor qualidade do produto final. Aparentemente, este estudo é o primeiro a abordar a influencia de um estresse crônico na resposta fisiológica e qualidade de filé de juvenis de beijupirá. Os resultados podem fornecer informações para avanços na criação dessa espécie, conduzindo a melhorias no bem estar animal, na qualidade do produto final e no aumento da produtividade

Submitted by Mario BC (mario@bc.ufrpe.br) on 2017-10-06T13:35:52Z No. of bitstreams: 1 Leilane Bruna Gomes dos Santos.pdf: 1226458 bytes, checksum: 61fd240c07e666550649b8bf8545b6e6 (MD5) / Made available in DSpace on 2017-10-06T13:35:52Z (GMT). No. of bitstreams: 1 Leilane Bruna Gomes dos Santos.pdf: 1226458 bytes, checksum: 61fd240c07e666550649b8bf8545b6e6 (MD5) Previous issue date: 2017-08-03 / The present study evaluated the gastrointestinal transit time, the anatomical characterization of the digestive tract of the cobia (Rachycentron canadum), Brazilian mojarraa (Eugerres brasilianus) and Common snook (Centropomus undecimalis) and the apparent digestibility of different ingredients by Brazilian mojarra. Eight juveniles of each species were sacrificed for anatomical characterization. Gastrointestinal transit time was evaluated in ten individuals of each species that were kept in cylindrical tanks of 300 L. The fish were fed to apparent satiety once daily with an experimental feed containing 10 g.kg -1 of oxide Of titanium. After 3 days, a second diet was offered with a similar composition but containing 10 g.kg -1 of chromium oxide. Every two hours, the feces were collected by sedimentation. The stomagomatic index was higher in the cobia (1.96 ± 0.53). On the other hand, the intestinal coefficient was higher in the Brazilian mojarra (0.57 ± 0.06). The digestive traits of the different species analyzed presented distinct anatomical and histological characteristics, probably due to their different eating habits. However, these anatomical differences had no effect on gastrointestinal transit time, which did not differ between species and was estimated at 18 h. In the digestibility experiment, six rations were prepared. The fish with 43.27g (± 12.90) and 15.40 cm (± 1.33) of weight and total length were distributed in six cylindrical-fiberglass tanks (300L; 12 fish per tank) in a system Recirculation. The dry matter (DM), crude protein (CP), ethereal extract (EE), mineral matter (MM), crude energy (CE) and amino acids (AA) coefficients were estimated. The CDA of the different nutrients of the evaluated ingredients presented values above 62.08%. The CD of the AA reflected the high digestibility of PB. The results show the capacity of the Brazilian mojarra to take advantage of both the animal and vegetable ingredients. / O presente estudo avaliou o tempo de trânsito gastrointestinal, a caracterização anatômica do trato digestivo do beijupirá (Rachycentron canadum), carapeba listrada (Eugerres brasilianus) e robalo-flecha (Centropomus undecimalis) e a digestibilidade aparente de diferentes ingredientes pela carapeba listrada. Oito juvenis de cada espécie foram sacrificados para a caracterização anatômica. O tempo de trânsito gastrointestinal foi avaliado em dez indivíduos de cada espécie que foram mantidos em tanques cilíndricos de 300 L. Os peixes foram alimentados até a saciedade aparente, uma vez por dia, com uma alimentação experimental contendo 10 g.kg-1 de óxido de titânio. Após 3 dias, foi oferecida uma segunda dieta com uma composição similar, mas contendo 10 g.kg-1 de óxido de cromo. A cada duas horas, as fezes foram coletadas por sedimentação. O índice estomagossomático foi maior no beijupirá (1,96 ± 0,53). Por outro lado, o coeficiente intestinal foi maior na carapeba (0,57 ± 0,06). Os traços digestivos das diferentes espécies analisadas apresentaram características anatômicas e histológicas distintas, provavelmente devido a seus diferentes hábitos alimentares. No entanto, essas diferenças anatômicas não tiveram efeito no tempo de trânsito gastrointestinal, que não diferiu entre as espécies e foi estimado em 18 h. No experimento de digestibilidade foram elaboradas seis rações. Os peixes com 43,27g (± 12,90) e 15,40 cm (± 1,33) de peso e comprimento total foram distribuídos em seis tanques cilíndro-cônicos de fibra de vidro (300L; 12 peixes por tanque) em sistema de recirculação. Foram estimados os coeficientes de digestibilidade aparente (CDA) de matéria seca (MS), proteína bruta (PB), extrato etéreo (EE), matéria mineral (MM), energia bruta (EB) e aminoácidos (AA). Os CDA dos diferentes nutrientes dos ingredientes avaliados, apresentaram valores acima de 62,08%. Os CDA dos aminoácidos (AA) refletiram a alta digestibilidade da PB. Os resultados encontrados evidenciam a capacidade da carapeba listrada de aproveitar tanto o ingrediente de origem animal quanto vegetal.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-09T12:13:39Z No. of bitstreams: 1 Carolina Notaro de Barros.pdf: 471792 bytes, checksum: 565309c707bb10b4d250687b7f4c6182 (MD5) / Made available in DSpace on 2017-02-09T12:13:39Z (GMT). No. of bitstreams: 1 Carolina Notaro de Barros.pdf: 471792 bytes, checksum: 565309c707bb10b4d250687b7f4c6182 (MD5) Previous issue date: 2012-02-08 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The indiscriminate use of antimicrobial drugs in aquaculture may cause development of drug-resistant bacteria, which become more difficult to be controlled and eliminated. Probiotics may represent an alternative prophylactic disease control, replacing the use of antibiotics. In this respect, this study isolated, tested and identified potential probiotic bacteria from the gut of cobia, Rachycentron canadum, a potential candidate for marine aquaculture. 40 animals were captured, 10 from a private hatchery and 30 from an offshore culture system (PE, Brazil) between November 2010 and July 2011. Fishes from the hatchery had weight of 139.30 ± 31.52 g and length of 27.13 ± 1.46 cm, while those from offshore culture system weighed 456.77 ± 264.46 g and had length of 37.29 ± 6.05 cm. 45 bacterial were isolated and tested in vitro against five known pathogenic species, Aeromonas hydrophila (IOC/FDA 110-36), Pseudomonas aeruginosa (ATCC 15442), Streptococcus agalactiae (ATCC 13813), Vibrio parahaemolyticus (ATCC 17802) and Vibrio vulnificus (ATCC 27562). Fifteen strains (33.33%) had antibacterial activity to at least one pathogen, while eight (17.77%) were inhibited all pathogens tested. There was significant difference (P<0.05) between percentage of potential probiotic obtained from different seasons, rainy and dry. Strains that presented the best results antagonism test in vitro were identified as Lactobacillus plantarum, Bacillus coagulans, Klebsiella spp., Bacillus circulans, Lactococcus lactis subsp. lactis and Bacillus firmus. The largest inhibition zone observed in the antagonism test was produced by B. circulans against V. vulnificus. Some potential probiotic species identified were characterized by others authors, but isolated from the intestine of other fish species. It is suggested in vivo antagonism tests are performed to prove the effectiveness of these bacteria as probiotic to cobia. / O uso indiscriminado de drogas antimicrobianas na aquicultura pode contribuir para o desenvolvimento de bactérias resistentes aos medicamentos, o que torna esses micro-organismos mais difíceis de serem controlados e eliminados. Probióticos podem representar uma alternativa profilática no controle de doenças, em substituição ao uso de antibióticos. Neste contexto, o estudo foi realizado com o objetivo de isolar, testar e identificar bactérias com potencial probiótico do beijupirá, Rachycentron canadum, potencial candidato para a piscicultura marinha. Foram coletados 40 animais, 10 na fase de berçário e 30 na fase de engorda em sistema offshore (PE, Brasil), no período de novembro de 2010 a julho de 2011. Os peixes coletados do berçário apresentaram peso de 139,30 ± 31,52 g e comprimento de 27,13 ± 1,46 cm, enquanto os animais provenientes do sistema offshore apresentaram peso de 456,77 ± 264,46 g e comprimento de 37,29 ± 6,05 cm. Foram obtidos 45 isolados bacterianos testados in vitro frente a cinco espécies patogênicas conhecidas, Aeromonas hydrophila (IOC/FDA 110-36), Pseudomonas aeruginosa (ATCC 15442); Streptococcus agalactiae (ATCC 13813); Vibrio parahaemolyticus (ATCC 17802) e Vibrio vulnificus (ATCC 27562). Quinze isolados (33,33%) apresentaram atividade antibacteriana a pelo menos um patógeno e oito (17,77%) inibiram todos os patógenos testados. Houve diferença significativa (P<0,05) na proporção de isolados potenciais probióticos obtidos nas distintas épocas do ano, chuvosa e seca. Os isolados que apresentaram os melhores resultados no teste de antagonismo in vitro foram identificados como Lactobacillus plantarum, Bacillus coagulans, Klebsiella spp., Bacillus circulans, Lactococcus lactis subsp. lactis e Bacillus firmus. O maior halo de inibição observado no teste de antagonismo foi produzido por B. circulans frente ao V. vulnificus. Algumas espécies potenciais probióticas identificadas já foram caracterizadas por outros autores, porém isoladas de intestino de outras espécies de peixes. Sugere-se a realização de testes de antagonismo in vivo para que seja comprovada a efetividade das bactérias como probióticas para o beijupirá.

Cobia fish cage is the most popular marine culture species raised in Phu Quoc Island, Vietnam. For its sustainable development, there is a need to determine the carrying capacity to avoid nega-tive marine environmental impact in the future. This study was carried out to collect water samples each two months at the lowest and highest tides at four points around the farming area in Rach Vem, Phu Quoc Island, Kien Giang Province from February to October 2011. Water quality in cobia cage culture was surveyed to assess the environmental status of coastal aquaculture areas including seven parameters such as DO, COD, BOD, TSS, TN, TP and Chlorophyll-a. These parameters are suitable to rear cobia fish cage in this area. Nitrogen and phosphorus are considered as the principal nutrients produced by the cobia fish farm and affecting water environment. This study found that the carrying capacity for fish cage farming in the area is 290.96 to 727.81 tons (based on total nitrogen) and 428.64 to 1,383.88 tons (based on total phosphorus) from February to Au-gust 2011. The maximum number of cobia cages should be, based on total nitrogen, from 64 to 266 and, based on total phosphorus, from 94 to 253. Moreover, this study examined the possibility of remote sensing and geographic information system (GIS) technique based on Object-based Image Analysis (OBIA) method by THEOS imagery for mapping of cage culture facilities and detect the location for cobia cage culture in study area. / Cá bớp nuôi lồng bè là một trong những loài cá nuôi phổ biến khu vực ven biển Phú Quốc, Việt nam. Nhằm phát triển bền vững vùng ven biển, đề tài thực hiện đã xác định và đánh giá hiện trạng môi trường nước và sức tải môi trường của nghề nuôi cá bớp lồng bè ở đảo Phú Quốc. Nghiên cứu này được thực hiện thông qua việc thu mẫu môi trường nước mỗi 2 tháng theo mức nước triều cao nhất và thấp nhất tại 4 điểm quanh khu vực nuôi tại ấp Rạch Vẹm, huyện Phú Quốc, tỉnh Kiên Giang từ tháng 02-10/2011. Chất lượng nước khu vực nuôi thủy sản cũng được khảo sát với 7 chỉ tiêu gồm DO, COD, BOD, TSS, TN, TP, Chlorophyll-a. Các thông số chất lượng môi trường này phù hợp nuôi cá bớp tại khu vực nghiên cứu dựa trên tiêu chuẩn chất lượng môi trường. Trong nghiên cứu này, đạm và lân là 2 thông số được sử dụng để tính toán sức tải môi trường. Sức tải môi trường được tính toán cho khu vực nuôi cá bớp dao động khoảng từ 290.96 tấn đến 727.81 tấn (tính trên hàm lượng đạm tổng số) và từ 428,64 tấn đến 1.383,88 tấn (tính trên hàm lượng lân tổng số) trong thời gian từ tháng 2 đến tháng 10 năm 2011. Số lượng tối đa lồng bè nuôi cá bớp khoảng từ 64 đến 266 (đạm tổng số) và từ 94 đến 253 (lân tổng số) dựa vào phân tích hồi quy tương quan. Bên cạnh đó, công nghệ viễn thám và hệ thống thông tin địa lý (GIS) đã được ứng dụng bằng cách sử dụng ảnh THEOS để xác định vị trí và phân bố không gian khu vực nuôi cá lồng bè dựa trên phương pháp phân tích đối tượng theo hướng (OBIA).

Cobia fish cage is the most popular marine culture species raised in Phu Quoc Island, Vietnam. For its sustainable development, there is a need to determine the carrying capacity to avoid nega-tive marine environmental impact in the future. This study was carried out to collect water samples each two months at the lowest and highest tides at four points around the farming area in Rach Vem, Phu Quoc Island, Kien Giang Province from February to October 2011. Water quality in cobia cage culture was surveyed to assess the environmental status of coastal aquaculture areas including seven parameters such as DO, COD, BOD, TSS, TN, TP and Chlorophyll-a. These parameters are suitable to rear cobia fish cage in this area. Nitrogen and phosphorus are considered as the principal nutrients produced by the cobia fish farm and affecting water environment. This study found that the carrying capacity for fish cage farming in the area is 290.96 to 727.81 tons (based on total nitrogen) and 428.64 to 1,383.88 tons (based on total phosphorus) from February to Au-gust 2011. The maximum number of cobia cages should be, based on total nitrogen, from 64 to 266 and, based on total phosphorus, from 94 to 253. Moreover, this study examined the possibility of remote sensing and geographic information system (GIS) technique based on Object-based Image Analysis (OBIA) method by THEOS imagery for mapping of cage culture facilities and detect the location for cobia cage culture in study area. / Cá bớp nuôi lồng bè là một trong những loài cá nuôi phổ biến khu vực ven biển Phú Quốc, Việt nam. Nhằm phát triển bền vững vùng ven biển, đề tài thực hiện đã xác định và đánh giá hiện trạng môi trường nước và sức tải môi trường của nghề nuôi cá bớp lồng bè ở đảo Phú Quốc. Nghiên cứu này được thực hiện thông qua việc thu mẫu môi trường nước mỗi 2 tháng theo mức nước triều cao nhất và thấp nhất tại 4 điểm quanh khu vực nuôi tại ấp Rạch Vẹm, huyện Phú Quốc, tỉnh Kiên Giang từ tháng 02-10/2011. Chất lượng nước khu vực nuôi thủy sản cũng được khảo sát với 7 chỉ tiêu gồm DO, COD, BOD, TSS, TN, TP, Chlorophyll-a. Các thông số chất lượng môi trường này phù hợp nuôi cá bớp tại khu vực nghiên cứu dựa trên tiêu chuẩn chất lượng môi trường. Trong nghiên cứu này, đạm và lân là 2 thông số được sử dụng để tính toán sức tải môi trường. Sức tải môi trường được tính toán cho khu vực nuôi cá bớp dao động khoảng từ 290.96 tấn đến 727.81 tấn (tính trên hàm lượng đạm tổng số) và từ 428,64 tấn đến 1.383,88 tấn (tính trên hàm lượng lân tổng số) trong thời gian từ tháng 2 đến tháng 10 năm 2011. Số lượng tối đa lồng bè nuôi cá bớp khoảng từ 64 đến 266 (đạm tổng số) và từ 94 đến 253 (lân tổng số) dựa vào phân tích hồi quy tương quan. Bên cạnh đó, công nghệ viễn thám và hệ thống thông tin địa lý (GIS) đã được ứng dụng bằng cách sử dụng ảnh THEOS để xác định vị trí và phân bố không gian khu vực nuôi cá lồng bè dựa trên phương pháp phân tích đối tượng theo hướng (OBIA).