Academic literature on the topic 'Oreochromis niloticus Linnaeus'

AbstractOreochromis mossambicus (Peters 1852) and Oreochromis niloticus niloticus Linnaeus, 1758 are two popular freshwater fishes introduced from Africa to India. There are many records of different species of trichodinid ectoparasites infesting wild and cultured cichlids in Africa, but no such study has been conducted on this parasitic group in India. The fishes Oreochromis mossambicus and Oreochromis niloticus niloticus were investigated for the occurrence of trichodinid ciliophorans. Oreochromis mossambicus was found positive for two species, viz., Trichodina centrostrigeata Basson, Van As & Paperna, 1983 and Paratrichodina africana Kazubski & El-Tantawy, 1986. Oreochromis niloticus niloticus was found not to be infested with any species of trichodinid ciliophorans, although, interestingly, Paratrichodina africana was first discovered in this host fish. Comparative descriptions and prevalence of these two above-mentioned species are presented.

Individuals of the tilapia species Oreochromis niloticus niloticus(Linnaeus, 1758) were caught in Lesina Lagoon during experimental sampling for the shrimp Penaeus kerathurus using fyke net traps from December 1999 to September 2000. The species O. niloticusis not native in Italian coastal waters, although attempts of tilapia culture in land-based aquaculture farms were occasionally carried out in the past. The number of individuals captured in the samples suggests a colonization of the area of Lesina lagoon. The highest catches were observed during July. In July, the individuals caught represented the 22.3±4.1 % of the total catch weight. Such colonization of a marine environment byO. niloticusniloticus is the first case reported for Italy. The occurrence of the species in Lesina lagoon is attributed to fish which escaped from fish farms in the area and entered the lagoon through the numerous streams and irrigation-drainage channels that outflow along the south coastline.

The pattern of morphometric differentiation among three populations of Tilapia (Oreochromis niloticus) sited in Koka, Ziway, and Langano lakes in the Ethiopian rift valley was examined. Morphometric differentiation was examined, compared and quantified by the use of twelve different body measurements in 391 specimens to generate baseline information for conservation and product improvement plans. The result revealed that comparisons of mean values of morphometric measurements in the three studied tilapia populations statistically significant differences (P<0.05). The Fulton’s condition factor (K) of Oreochromi niloticus samples collected from Lakes Koka, Ziway, and Langano was 1.48, 1.2, and 0.66, respectively. The Discriminant Function Analysis performed on seven variables led to a correct classification in 90.5 % of cases. Differences observed between samples in this study indicated that there is important morphometric variation between the studied tilapia populations. Plotting the two significant canonical discriminant functions separated the Lake Langano population from the other two.

Avaliou-se o hemograma e a morfologia celular em amostras de sangue periférico obtidas de 10 peixes da espécie Oreochromis niloticus. Parte das mesmas foi utilizada para o estudo da hematimetria, isto é, contagem de eritrócitos (x = 2,35 x 106/mm3 ± 0,12), taxa de hemoglobina, (x = 7,04 g/dL ± 0,38), hematócrito (x = 27,85% ± 1,62), HCM (x = 30,31pg ± 1,64), VCM (x = 118,6p3 ± 3,53), CHCM (x = 25,78% ± 1,72), contagem global de leucócitos (x = 16,08 x 103/mm3 ± 1,28), contagem de trombócitos (x = 61,69 x 103/mm3 ± 5,96), sendo a avaliação da morfologia das células do sangue reallizada através do estudo de extensões sangüíneas submetidas à coloração de Wright. Os eritrócitos e trombócitos nucleados apresentaram-se elípticos; neutrófilos e eosinófilos esféricos de tamanho variável, com o núcleo também esférico, apresentaram citoplasmas abundantes, ligeiramente basófilo e altamente acidófilo, respectivamente. Não foram vistas as formas polimorfonucleares dessas células. Os basófilos apresentaram núcleo esférico e granuiações metacromáticas. Os monócitos e os linfócitos assemelharam-se morfologicamente aos dos mamíferos.

This study provides the first investigation on acquisition of parasites in invasive O. niloticus by parasite species of native Cichlidae from the Igarapé Fortaleza basin, Northern Brazil. There were examined 576 specimens of 16 species of native cichlids and invasive O. niloticus collected in the main channel and the floodplain area of this tributary of Amazon River. The invasive O. niloticus was poorly parasitized having only Ichthyophthirius multifiliis, Trichodina centrostrigeata, Paratrichodina africana, Trichodina nobilis (Protozoa) and Cichlidogyrus tilapiae (Monogenoidea), and this host has not acquired any parasite species common to the native ichthyofauna region. In contrast, species of native cichlids showed rich fauna of parasites with predominance of Monogenoidea species, larvae and adults of Nematoda, Digenea, Cestoidea and Acanthocephala, besides four species of Protozoa and four Crustacea. However, only T. nobilis was acquired by native fish, the Aequidens tetramerus, which is a new host for this exotic Trichodinidae. In O. niloticus, well established in the region, the small number of helminth species may be associated with its rusticity, good adaptation in the new environment and also the presence of native parasites with relative specificity, but without ability to complete its life cycle in this invasive host of this ecosystem.

This study was aimed to investigate the effect of Buchholcia coriacea on the masculinization of Oreochromis niloticus. Five days old mixed sex of O. niloticus (mean weight 0.2g, mean length 0.45mm) were subjected to powdered B. coriacea seeds meal (BSM) at 0, 2, 4, 6, 8, 10g/kg twice daily for 1 month in an indoor experimental plastic basin capacity (50cm in diameter and 30cm deep) in duplicates with a total of six treatments in a complete randomized design. After which there were later fed with a normal diet in an outdoor concrete tank of size 1m3 for another one month. One way ANOVA and LSD were used to analyze the experimental data. The result obtained in this study showed that fish fed with 4g/kg BSM powdered BSM had the highest number (83.33%) of males which was significantly higher (p<0.05) compared to all other treatments categories. The highest survival rate (100%) was recorded in fish fed with 6g/kg BSM. The highest mean length, mean weight and weight gain observed are 0.488mm, 4.68g, and 4.65g respectively. The result of the histology showed that B. coriacea altered the sex of O. niloticus due to the presence of a hormone called dopamine in the kola. Conclusively, B. coriacea showed potential reproduction control in Oreochromis niloticus.

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The objective was proportional an analysis in the processing of Nile tilapia in different weight ranges. A total of 200 tilapias were used, separated into four weight groups: P1 (180 to 220 g); P2 (280-320 g); P3 (380-420 g) and P4 (480-520 g), derived from a farmers association of fish in net-tank from the hydroelectric Governor José Richa-Salto Caxias, Pr. The fish were processed in an industrial environment . For statistical analysis, we used the analysis of variance, followed by F test at 5% significance level, and when significant Tukey test. The found average weights were P1 (206g), P2 (297g); P3 (382g) and P4 (491g). A clean trunk proceeds analysis was significant for P2 weight ranges (51.15%), P3 (51.36%) and P4 (53.01%). Proximate analysis for clean trunks were used, and the weight ranges P3 and P4 were significant for protein and fat. As the production cost and manufacturing proceeds for the clean trunk, the weight range is indicated P2
O objetivo do trabalho foi o de proporcionar uma análise no processamento da tilápia do Nilo em diferentes faixas de peso. Foram utilizados um total de 200 tilápias, separadas em quatro grupos de pesos: P1 (180 a 220 g); P2 (280 a 320 g); P3 (380 a 420 g) e P4 (480 a 520 g), oriundos de uma associação de aquicultores de peixes em tanques-rede do reservatório da Usina Hidrelétrica Governador José Richa-Salto Caxias, PR. Os peixes foram processados em um ambiente industrial. Para a análise estatística, foi utilizada a análise de variância, seguido do teste F em 5 % de significância, e o teste de Tukey quando significativo. Os pesos médios encontrados foram P1 (206g), P2 (297g); P3 (382g) e P4 (491g). A análise de rendimento de tronco limpo mostrou-se significativa para as faixas de peso P2 (51,15%), P3 (51,36%) e P4 (53,01%). Para análise centesimal foram utilizados os troncos limpos, e as faixas de peso P3 e P4 foram significativas para proteína e gordura. Quanto ao custo de produção e rendimento industrial para obter o tronco limpo, a faixa de peso indicada é o P2

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A finalidade do presente trabalho foi realizar estudos citogenético, morfológico, metabólico, hormonal, composição corporal e produção aquícola em tilápia do Nilo, Oreochromis niloticus revertida sexualmente. Em uma primeira etapa, estudou-se o desempenho produtivo das tilápias. Tilápias sexo revertidas foram comparadas com tilápias machos e fêmeas durante as fases de reversão, alevinagem e cultivo de juvenis e com tilápias sexadas na fase de engorda. As larvas, ao início da fase de reversão, apresentavam comprimento inferior a 11 mm e foram alimentadas por 28 dias com uma dieta contendo o hormônio 17-α-metiltestosterona, na dose de 60 mg/ kg de ração. A análise histológica das gônadas revelou uma taxa de reversão para machos de 93,33 %. O hormônio, 17-α- metiltestosterona, incorporado à dieta, não resultou em aumento de taxa de mortalidade que durante as fases de reversão, alevinagem, cultivo de juvenis e engorda foi baixa e variou de 2,5 % a 10,2 %. O incremento em peso e comprimento dos peixes revertidos sexualmente, apesar de não ser estatisticamente significativo, foi superior ao do grupo controle nas 4 fases. Durante a fase de reversão sexual o grupo experimental apresentou maior incremento de peso do que de comprimento (b: 2,98) quando comparado ao grupo controle (b: 3,69). Os resultados obtidos de fator de condição alométrico sugerem que o estado fisiológico do grupo controle foi similar ao revertido. Na segunda etapa da pesquisa foram comparadas tilápias do Nilo, machos e fêmeas em reprodução com tilápias revertidas sexualmente em fase final de engorda. Através da análise das metáfases mitóticas foi possível a adoção de um método capaz de identificar o sexo genotípico das tilápias sexo revertidas. Foram identificados o grupo macho controle (MC), o grupo fêmea controle (FC), o grupo macho que após o tratamento hormonal se mantém macho (MM) e...

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Resumo: A finalidade do presente trabalho foi realizar estudos citogenético, morfológico, metabólico, hormonal, composição corporal e produção aquícola em tilápia do Nilo, Oreochromis niloticus revertida sexualmente. Em uma primeira etapa, estudou-se o desempenho produtivo das tilápias. Tilápias sexo revertidas foram comparadas com tilápias machos e fêmeas durante as fases de reversão, alevinagem e cultivo de juvenis e com tilápias sexadas na fase de engorda. As larvas, ao início da fase de reversão, apresentavam comprimento inferior a 11 mm e foram alimentadas por 28 dias com uma dieta contendo o hormônio 17-α-metiltestosterona, na dose de 60 mg/ kg de ração. A análise histológica das gônadas revelou uma taxa de reversão para machos de 93,33 %. O hormônio, 17-α- metiltestosterona, incorporado à dieta, não resultou em aumento de taxa de mortalidade que durante as fases de reversão, alevinagem, cultivo de juvenis e engorda foi baixa e variou de 2,5 % a 10,2 %. O incremento em peso e comprimento dos peixes revertidos sexualmente, apesar de não ser estatisticamente significativo, foi superior ao do grupo controle nas 4 fases. Durante a fase de reversão sexual o grupo experimental apresentou maior incremento de peso do que de comprimento (b: 2,98) quando comparado ao grupo controle (b: 3,69). Os resultados obtidos de fator de condição alométrico sugerem que o estado fisiológico do grupo controle foi similar ao revertido. Na segunda etapa da pesquisa foram comparadas tilápias do Nilo, machos e fêmeas em reprodução com tilápias revertidas sexualmente em fase final de engorda. Através da análise das metáfases mitóticas foi possível a adoção de um método capaz de identificar o sexo genotípico das tilápias sexo revertidas. Foram identificados o grupo macho controle (MC), o grupo fêmea controle (FC), o grupo macho que após o tratamento hormonal se mantém macho (MM) e...
Abstract: Not available
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The toxocariasis is a disease of worldwide distribution, caused by nematodes Toxocara canis and T. cati, parasites whose definitive hosts are dogs and cats, respectively. These agents can also infect humans, and their larvae can migrate through the body, causing the syndrome of visceral larva migrans (visceral toxocariasis) or ocular (ocular toxocariasis). Consumption of raw or undercooked meat of animals such as ruminants and poultry has been considered as one of the routes of transmission of the disease to humans. Evaluation of the migration of larvae Toxocara spp. in fish is scarce in the literature. This study aimed to evaluate the ability of Toxocara canis to infect and migrate through the tissues of experimentally infected fish. Forty-nine Nile tilapia (Oreochromis niloticus, Linnaeus 1757) were evaluated. Two groups were formed for the assessment of infection. Group I consisted of 35 animals infected by oral gavage with 1,000 T. canis-embryonated eggs (IG). The second group contained 14 animals that received 1.0 ml PBS by oral gavage and served as a control group (CG). To recover the larvae, 5 animals from IG and two animals from CG were euthanised at 1, 2, 5, 10, 15, 30 and 60 days post-infection. Samples of the liver, brain, gills, muscle and intestinal content were collected and subjected to acid digestion and the modified Baermann method. There were no T. canis larvae detected at any time point during this experiment, but embryonated eggs were found in the intestinal contents. Our findings suggest that tilapia could serve as a disseminating vehicle of Toxocara spp. in aquatic environments.
A toxocaríase é uma doença de distribuição mundial, causada pelos nematódeos Toxocara canis e T. cati, parasitos cujos hospedeiros definitivos são os cães e os gatos, respectivamente. Esses agentes podem também infectar seres humanos, e suas larvas podem migrar pelo organismo, ocasionando a síndrome de larva migrans visceral (toxocaríase visceral) ou ocular (toxocaríase ocular). O consumo de carne crua ou mal cozida de animais, como ruminantes e aves, tem sido considerado como uma das vias de transmissão da doença para o ser humano. A avaliação da migração de larvas de Toxocara spp. em peixes é escasso na literatura. Com objetivo de criar um modelo experimental e avaliar a viabilidade da infecção e migração tecidual de Toxocara canis em peixes, foram utilizadas 49 tilápias (Oreochromis niloticus), com peso aproximado de 100 a 150 g, obtidas de uma central de piscicultura. Dois grupos foram formados para avaliação da infecção. O Grupo I (GI) composto por 35 animais infectados oralmente, por gavagem, com 1000 ovos larvados de T. canis diluídos em 1,0 mL de solução salina tamponada (PBS pH 7,0). O segundo grupo (GII) constituído por 14 animais, que receberam, pela mesma via, 1,0 mL de PBS, e serviram como controle. Os peixes foram mantidos em caixas plásticas, com fluxo de água contínuo, e alimentados com ração comercial para peixes duas vezes/dia. Nos dias 1, 2, 5, 10, 15, 30 e 60 pós-infecção, cinco animais do GI e dois do GII foram sacrificados, e amostras de fígado, sistema nervoso central, arcos branquiais, musculatura (filé) e o conteúdo intestinal foram coletados e submetidos ao processo de digestão em ácido clorídrico 0,5% e ao método de Baermann, modificado, para recuperação das larvas. Não foram encontradas larvas de T. canis em nenhum dos momentos deste experimento. No conteúdo intestinal, foram encontrados ovos larvados (5 ovos em média), em todas as tilápias infectadas. Os ovos de T. canis podem ser dispersados no ambiente aquático pela tilápia.

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The canning industry in Brazil has been facing serious problems of supply, since the extractive fishery of the main prime-materia that is the fishing doesn’t supply the demand of the seccion, which has done a high degree of idleness and/or the necessity to import fish from other countries, which suggests the search of new products. The aim was to develop the kept by canning tilapia, using tilapias with medium weight of 100,02 ±19,89 g which, the kept, were called as “charuto” (trunk without head, paddles, gutteds and flakes). The “charutos” were put into brine, pre-boiled and then added sauce of covering. Cans were closed in semiautomatic and autoclaved “recravadeira”, three termic treatments of 15, 20 and 30 minutes, using constant temperature of 121° C. The choice of the best portion of pickle was done by sensorial analysis by color, aroma, flavor, texture and general quality. To qualify e classifying the pickles were carried out nutritional, phisical-chemical analyses, test of esterility and test of paired preference. At the acceptability analysis of the pickle of tilapia, all the termics treatments were approved in the test, but there was not diference between the treatments (P < 0,05). Nevertheless, the treatments of 15 and 20 minutes showed inferior grade to 7 for flavor, what made possible the choice of the 30 minute-treatment as the best, being chosen to be valuated in the test of preference, with commercial conservation. The phisical-chemical traits of the pickles showed the following results: 74,72% humidity, 18,31% proteins, 4,78% ashes, 2,31% lipids, 94,03 Kcal total caloric value, 726,32 mg calcium, 0,90 mg ferro and 333,75 mg sodium. The nutricional information for one portion of 60g of the product was: caloric value 60 Kcal, carbohidrats 0 g, proteins 11 g, total fat 1,5 g, satured fat 0,5 g, cholesterol 36 mg, feed fiber 0 g, calcium 435,8 mg, ferro 0,54 mg and sodium 200 mg. The incubation test accused no contamination of the product and in the paired preference test there was no diference (P < 0,05) between the tilapia conservation and the conservation of commercial fish. Conclude that the consevation of tilapia shows phisical-chemicals, nutricional e sensorial compatibility with the similar commercial products, which confirm the viability of the product for the market of pickles.
A indústria de conserva no Brasil vem passando por problemas graves de abastecimento, visto que a pesca extrativa da sua principal matéria-prima que é a sardinha, não atende a demanda do setor, o que tem provocado um alto grau de ociosidade e/ou a necessidade de importar pescado de outros países, o que sugere a busca de novos produtos. Objetivou-se desenvolver uma conserva mediante o enlatamento de tilápia, utilizando exemplares com peso médio de 100,0 ±19,8 g que, após tratadas, foram denominadas de “charuto” (tronco sem cabeça, sem nadadeiras, evisceradas e escamadas). Os “charutos” foram colocados em salmoura, na lata, pré-cozido e em seguida adicionado o molho de cobertura. As latas foram fechadas em recravadeira semi-automática e autoclavadas em três tratamentos térmicos de 15, 20 e 30 minutos, utilizando temperatura constante de 121° C. A escolha do melhor lote de conserva foi feita pelo teste de aceitabilidade em relação aos atributos: cor, aroma, sabor, textura e qualidade geral. Para qualificar e classificar a conserva foram realizadas análises físico-químicas, nutricional e teste de esterilidade. Foi ainda realizado teste de preferência entre a conserva em estudo e uma já existente no comércio com outro tipo de peixe. Todos os tratamentos térmicos foram aprovados não havendo diferença entre os tratamentos (P < 0,05). No entanto, os tratamentos de 15 e 20 minutos apresentaram nota inferior a 7 no atributo sabor, o que possibilitou a eleição do tratamento de 30 minutos como o melhor, sendo a escolhida para ser avaliada no teste de preferência. A composição físico-química da conserva apresentou os seguintes resultados: 74,72% de umidade, 18,31% de proteínas, 4,78% de cinzas, 2,31% de lipídeos, 94,03 Kcal de valor calórico total, 726,32 mg de cálcio, 0,90 mg de ferro e 333,75 mg de sódio. A informação nutricional para uma porção de 60g do produto foi: valor calórico 60 Kcal, carboidratos 0 g, proteínas 11 g, gordura total 1,5 g, gordura saturada 0,5 g, colesterol 36 mg, fibra alimentar 0 g, cálcio 435,8 mg, ferro 0,54 mg e sódio 200 mg. No teste de esterilidade não foi constatada nenhuma alteração do produto e no teste de preferência pareada não houve diferença (P < 0,05) entre a conserva de tilápia e a conserva de peixe comercial. Concluiu-se que a conserva de tilápia apresenta condições físico-químicas, nutricionais e sensoriais compatíveis com os produtos comerciais similares, o que confirma a viabilidade do produto para o mercado de conservas.

Dans ce travail de thèse de doctorat, deux objectifs ont été poursuivis à savoir : i) évaluer la structure génétique des populations du tilapia du Nil (Oreochromis niloticus, Linnaeus, 1758) pour orienter les mesures de gestion à l’échelle de la sous-région du bassin du Congo; ii) et évaluer l’héritabilité des traits de croissance afin d’envisager une amélioration génétique de ladite espèce. Dans la perspective de déterminer la structuration génétique du tilapia du Nil dans le bassin du Congo à l'aide de récents outils génomiques de type GBS, 13,792 SNPs neutres étaient identifiés à partir de 438 tilapias du Nil collectés au Cameroun, en République Centrafricaine et en République Démocratique de Congo. La présence de groupements génétiques distincts a été élucidée par la méthode de regroupement bayésien implémentée dans le programme Admixture exécuté en utilisant 2000 bootstraps avec un nombre de groupes (K) variant de 1 à 14. L’estimation du flux génique potentiel, entre les sites, a été réalisée à l’aide du logiciel Treemix et l’évaluation de degré d’apparentement par paire entre deux individus d’un même site ou écosystème (utilisant les indices de relation de parenté ou relatedness, AJK), par vcftools. L’estimation de l’héritabilité des traits de croissance du tilapia du Nil a été réalisée en utilisant les données de 660 poissons cultivés dans les hapas placés en étang entre 185 et 209 jours d’expérience. Les mesures de masse corporelle et de longueur standard ont été prises in situ tandis que le facteur de condition a été déduit en utilisant la formule de Fulton. La détermination de données liées à la morphologie a été obtenue par analyse Procruste généralisée. Une analyse utilisant le modèle animal mixte a été appliquée à ces traits morphométriques pour estimer les différentes composantes de variance génétique et environnementale à partir desquelles l'héritabilité de chaque caractère, les effets des facteurs environnementaux et les corrélations génétiques entre les traits ont été déduits. Les résultats de l’analyse de structure sur les 13,792 marqueurs neutres ont révélé l’existence d'une structuration génétique mise en évidence avec l’identification de 5 populations génétiquement différentes (moyenne Fst = 0.079; CI: 0.073 à 0.086, P-valeur = 0.001). Il ressort de cette étude qu’il y a eu flux de gènes entre certains sites et qu’il y a moins d’individus apparentés dans les rivières et lacs par rapport aux piscicultures.
Dans ce travail de thèse de doctorat, deux objectifs ont été poursuivis à savoir : i) évaluer la structure génétique des populations du tilapia du Nil (Oreochromis niloticus, Linnaeus, 1758) pour orienter les mesures de gestion à l’échelle de la sous-région du bassin du Congo; ii) et évaluer l’héritabilité des traits de croissance afin d’envisager une amélioration génétique de ladite espèce. Dans la perspective de déterminer la structuration génétique du tilapia du Nil dans le bassin du Congo à l'aide de récents outils génomiques de type GBS, 13,792 SNPs neutres étaient identifiés à partir de 438 tilapias du Nil collectés au Cameroun, en République Centrafricaine et en République Démocratique de Congo. La présence de groupements génétiques distincts a été élucidée par la méthode de regroupement bayésien implémentée dans le programme Admixture exécuté en utilisant 2000 bootstraps avec un nombre de groupes (K) variant de 1 à 14. L’estimation du flux génique potentiel, entre les sites, a été réalisée à l’aide du logiciel Treemix et l’évaluation de degré d’apparentement par paire entre deux individus d’un même site ou écosystème (utilisant les indices de relation de parenté ou relatedness, AJK), par vcftools. L’estimation de l’héritabilité des traits de croissance du tilapia du Nil a été réalisée en utilisant les données de 660 poissons cultivés dans les hapas placés en étang entre 185 et 209 jours d’expérience. Les mesures de masse corporelle et de longueur standard ont été prises in situ tandis que le facteur de condition a été déduit en utilisant la formule de Fulton. La détermination de données liées à la morphologie a été obtenue par analyse Procruste généralisée. Une analyse utilisant le modèle animal mixte a été appliquée à ces traits morphométriques pour estimer les différentes composantes de variance génétique et environnementale à partir desquelles l'héritabilité de chaque caractère, les effets des facteurs environnementaux et les corrélations génétiques entre les traits ont été déduits. Les résultats de l’analyse de structure sur les 13,792 marqueurs neutres ont révélé l’existence d'une structuration génétique mise en évidence avec l’identification de 5 populations génétiquement différentes (moyenne Fst = 0.079; CI: 0.073 à 0.086, P-valeur = 0.001). Il ressort de cette étude qu’il y a eu flux de gènes entre certains sites et qu’il y a moins d’individus apparentés dans les rivières et lacs par rapport aux piscicultures.
On a démontré que l’héritabilité au sens strict (h²) de la masse corporelle était élevée (0.67±0.30), modérée pour la morphologie (0.30 ± 0.12), faible pour la longueur standard (0.10 ± 0.10) et le facteur de condition (0.03 ± 0.04). L’héritabilité au sens large (H²) a varié de 0.22 ± 0.13 à 0.93 ± 0.10 pour tous les traits. La corrélation génétique entre la masse corporelle et la morphologie (0.91) était élevée mais moyenne entre la longueur standard et la morphologie (0.21) ainsi qu’entre la masse corporelle et la longueur standard (0.20). La corrélation phénotypique entre la masse corporelle et la longueur standard (0.95) était élevée tandis qu’elle était moyenne entre la longueur standard et la morphologie (0.21) ainsi qu’entre la masse corporelle et la morphologie (0.27). Au vu de ces résultats, on peut conclure qu’il y a existence d'une structuration génétique pouvant permettre une gestion et utilisation durables de l’espèce tilapia du Nil dans le cadre des activités piscicoles et d’ensemencement. L’existence d’une bonne diversité́ génétique associée à l’héritabilité des caractères de croissance augure de bonnes perspectives pour des programmes d’amélioration génétique de l’espèce dans la sous-région du bassin du Congo.
On a démontré que l’héritabilité au sens strict (h²) de la masse corporelle était élevée (0.67±0.30), modérée pour la morphologie (0.30 ± 0.12), faible pour la longueur standard (0.10 ± 0.10) et le facteur de condition (0.03 ± 0.04). L’héritabilité au sens large (H²) a varié de 0.22 ± 0.13 à 0.93 ± 0.10 pour tous les traits. La corrélation génétique entre la masse corporelle et la morphologie (0.91) était élevée mais moyenne entre la longueur standard et la morphologie (0.21) ainsi qu’entre la masse corporelle et la longueur standard (0.20). La corrélation phénotypique entre la masse corporelle et la longueur standard (0.95) était élevée tandis qu’elle était moyenne entre la longueur standard et la morphologie (0.21) ainsi qu’entre la masse corporelle et la morphologie (0.27). Au vu de ces résultats, on peut conclure qu’il y a existence d'une structuration génétique pouvant permettre une gestion et utilisation durables de l’espèce tilapia du Nil dans le cadre des activités piscicoles et d’ensemencement. L’existence d’une bonne diversité́ génétique associée à l’héritabilité des caractères de croissance augure de bonnes perspectives pour des programmes d’amélioration génétique de l’espèce dans la sous-région du bassin du Congo.
Strict heritability (h²) of body mass was shown to be high (0.67 ± 0.30), moderate for morphology (0.30 ± 0.12), low for standard length (0.10 ± 0.10), and condition factor (0.03 ± 0.04). Heritability in the broad sense (H²) ranged from 0.22 ± 0.13 to 0.93 ± 0.10 for all traits. The genetic correlation between body mass and morphology (0.91) was high but average between standard length and morphology (0.21) and between body weight and standard length (0.20). The phenotypic correlation between body mass and standard length (0.95) was high while it was average between standard length and morphology (0.21) as well as between body mass and morphology (0.27). In view of these results, it can be concluded that there is a genetic structure that can allow sustainable management and use of the Nile tilapia species in the context of fish farming and fish seed production. The existence of a good genetic diversity associated with the heritability of growth traits is promising for the development of genetic improvement programs of the of Nile tilapia species in the Congo Basin sub region
Strict heritability (h²) of body mass was shown to be high (0.67 ± 0.30), moderate for morphology (0.30 ± 0.12), low for standard length (0.10 ± 0.10), and condition factor (0.03 ± 0.04). Heritability in the broad sense (H²) ranged from 0.22 ± 0.13 to 0.93 ± 0.10 for all traits. The genetic correlation between body mass and morphology (0.91) was high but average between standard length and morphology (0.21) and between body weight and standard length (0.20). The phenotypic correlation between body mass and standard length (0.95) was high while it was average between standard length and morphology (0.21) as well as between body mass and morphology (0.27). In view of these results, it can be concluded that there is a genetic structure that can allow sustainable management and use of the Nile tilapia species in the context of fish farming and fish seed production. The existence of a good genetic diversity associated with the heritability of growth traits is promising for the development of genetic improvement programs of the of Nile tilapia species in the Congo Basin sub region
In this PhD thesis work, two objectives were pursued: i) to assess the genetic structure of Nile tilapia populations (Oreochromis niloticus, Linnaeus, 1758) in order to guide management strategies at the sub-regional scale; region; ii) and assess the heritability of the growth traits in order to consider a genetic improvement of the species. In order to determine the genetic structuring of Nile tilapia in the Congo Basin using recent GBS-type genomic tools, 13,792 neutral SNPs were identified from 438 Nile tilapias collected in Cameroon, Central African Republic and Democratic Republic of Congo. The presence of distinct genetic groupings was elucidated by the Bayesian clustering method implemented in the Admixture program run using 2000 bootstraps with a number of groups (K) ranging from 1 to 14. The estimation of potential gene flow between sites, was performed using Treemix software and peer paired degree evaluation between two individuals from the same site or ecosystem (using kinship or relatedness indices, AJK), by vcftools. The assesment of the heritability of Nile tilapia growth traits was performed using data from 660 fish grown in hapas placed in a pond between 185 and 209 days of experience. The body mass and standard-length measurements were taken in situ while the condition factor was deduced using the Fulton formula. Determining morphology-related data was obtained by generalized Procrustes analysis. An analysis using the mixed animal model was applied to these morphometric traits to estimate the different components of genetic and environmental variances from which the heritability of each trait, the effects of environmental factors and the genetic correlations between traits were derived. The results of the structural analysis on the 13,792 neutral markers revealed the existence of a genetic structure highlighted with the identification of 5 genetically different populations (average Fst = 0.079, CI: 0.073 to 0.086, P-value = 0.001). This study shows that there has been gene flow between some sites and that there are fewer inbred individuals in the rivers and lakes while fish farmers have been more consanguineous.
In this PhD thesis work, two objectives were pursued: i) to assess the genetic structure of Nile tilapia populations (Oreochromis niloticus, Linnaeus, 1758) in order to guide management strategies at the sub-regional scale; region; ii) and assess the heritability of the growth traits in order to consider a genetic improvement of the species. In order to determine the genetic structuring of Nile tilapia in the Congo Basin using recent GBS-type genomic tools, 13,792 neutral SNPs were identified from 438 Nile tilapias collected in Cameroon, Central African Republic and Democratic Republic of Congo. The presence of distinct genetic groupings was elucidated by the Bayesian clustering method implemented in the Admixture program run using 2000 bootstraps with a number of groups (K) ranging from 1 to 14. The estimation of potential gene flow between sites, was performed using Treemix software and peer paired degree evaluation between two individuals from the same site or ecosystem (using kinship or relatedness indices, AJK), by vcftools. The assesment of the heritability of Nile tilapia growth traits was performed using data from 660 fish grown in hapas placed in a pond between 185 and 209 days of experience. The body mass and standard-length measurements were taken in situ while the condition factor was deduced using the Fulton formula. Determining morphology-related data was obtained by generalized Procrustes analysis. An analysis using the mixed animal model was applied to these morphometric traits to estimate the different components of genetic and environmental variances from which the heritability of each trait, the effects of environmental factors and the genetic correlations between traits were derived. The results of the structural analysis on the 13,792 neutral markers revealed the existence of a genetic structure highlighted with the identification of 5 genetically different populations (average Fst = 0.079, CI: 0.073 to 0.086, P-value = 0.001). This study shows that there has been gene flow between some sites and that there are fewer inbred individuals in the rivers and lakes while fish farmers have been more consanguineous.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
With the growth of the aquaculture even small mortality rates take big losses, so this study was goal to evaluate possible causes of death in fish at industrial scale in transportation. So eight abiotic variables of water quality were examined: water temperature, dissolved oxygen, ammonia, nitrate, nitrite, pH, conductivity and turbidity, as well transportation time and density and gradient difference of the variables from the catch to the end transport. For this ten samplings between setembro/2013 and fevereiro/2014 were performed in western Paraná. The water sampling were performed at three different times during the transport process, because it was necessary to subdivide them for obtain the difference in gradient of environmental variables and identify which is the most critical step of the process. To characterize the quality of water, the abiotic variables were summarized using Principal Component Analysis (PCA). The combined variation of variables was summarized in an index called variation in environmental gradient (ΔG). Further, to verify which variables were associated with mortality, the Probit model was used in the linear regressions. Both analyzes were evaluated at a significance level of five percent. APC in three main axes, which indicated high concentrations of nitrite for time pond, in loading the variables analyzed were satisfactory and unloading time had water with high levels of nitrate, electrical conductivity and ammonia. In linear regressions nitrite was significant for mortality in pond time, water temperature and electrical conductivity for loading and ammonia and dissolved oxygen for unloading time. Abrupt changes in gradient of the variables did not cause fish mortality and nitrogenous waste found in large concentrations at the end of the transport interfered in fish mortality. With that suggest that fish are subjected to stress before the transport process due to bad quality of water pond.
Com o crescimento da aquicultura até mesmo pequenas taxas de mortalidade assumem grandes prejuízos, logo, este estudo teve o objetivo de avaliar possíveis causas de óbitos em peixes no transporte em escala industrial. Assim, foram examinadas oito variáveis abióticas de qualidade de água: temperatura da água, oxigênio dissolvido, amônia, nitrato, nitrito, pH, condutividade elétrica e turbidez, além de tempo e densidade de transporte e diferença de gradiente das variáveis desde a captura até o final do transporte. Para isto foram realizadas dez amostragens entre setembro/2013 e fevereiro/2014, na região oeste do Paraná. As coletas de água foram realizadas em três momentos diferentes durante o processo de transporte, pois foi necessário subdividi-las para obter a diferença de gradiente das variáveis ambientais assim como identificar qual a etapa mais crítica do processo. Para caracterizar a qualidade da água, as variáveis abióticas foram sumarizadas através de Análise de Componentes Principais (ACP). A amplitude conjunta das variáveis foi sumarizada num índice denominado variação no gradiente ambiental (∆G). Na sequência, para verificar quais variáveis estiveram associadas às mortalidades, foi utilizado o modelo Probito nas regressões lineares. Ambas as análises foram avaliadas ao nível de significância de cinco por cento. Na APC foram retidos três eixos principais, os quais indicaram altas concentrações de nitrito para o tempo viveiro, no momento carregamento as variáveis analisadas apresentaram-se satisfatórias e o momento descarregamento apresentou água com elevados índices de nitrato, condutividade elétrica e amônia. Nas regressões lineares o nitrito mostrou-se significante para mortalidade no tempo viveiro, temperatura da água e condutividade elétrica para o carregamento e oxigênio dissolvido e amônia no momento descarregamento. Mudanças abruptas de gradiente das variáveis não ocasionaram mortalidade dos peixes e os resíduos nitrogenados encontrados em grandes concentrações ao final do transporte interferem na mortalidade dos peixes. Com isso pode-se sugerir que os peixes estão submetidos à estresse antes do processo de transporte devido má qualidade da água no momento viveiro.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
The objective of this study was to evaluate the efficiency of ozonated water as an antimicrobial agent in the Nile tilapia (O. niloticus) processing. Samples of whole tilapia and fillets were washed with cold water (11 ° C), without ozone (0 ppm - control) and with ozone (0.5; 1.0; 1.5 ppm) for 0; 5; 10; and 15 minutes. Microbiological parameters (total count of mesophilic, Staphylococcus aureus positive coagulase counts, fecal coliforms and the presence of Salmonella sp.) and physicochemical parameters (pH, color, TBA) were evaluated in order to check the microbiological load reduction and possible changes on pH, color and lipid oxidation (TBA) of fillets. The most effective ozone concentration on reducing the microbial load of the surface of tilapia was 1.5 ppm, reducing the initial populations of mesophilic bacteria in 91.78%. At this concentration (1.5 ppm), it was effective within the first 5 min., reducing the microbial load of 71.23%. In fillet washing, 1.5 ppm ozone concentration also showed the greatest reduction of mesophilic bacteria 70.19%. The treatment with ozonated water of fillets showed no influence on the pH and color of the fillets, however, there was an increase in the TBA value (1.5 ppm of O3 for 15 min.), showing that lipid oxidation occurred, but below the thresholds that make them unfit for consumption. The results showed that the ozonated water has been effective in reducing the microbial load of the fish during processing. The cost of electricity consumption used for ozone generation demonstrated its feasibility of use
O objetivo com o presente trabalho foi avaliar a eficiência da água ozonizada como agente antimicrobiano no processamento da tilápia do Nilo (O. niloticus). Amostras de tilápia inteira e filés foram imersas em água gelada (11°C) sem ozônio (0 ppm - controle) e com ozônio (0,5; 1,0; 1,5 ppm) durante 0; 5; 10; e 15 minutos. Parâmetros microbiológicos (contagem total de mesófilos, contagem de Staphylococcus aureus coagulase positivo, coliformes termotolerantes e presença de Salmonella sp.) e físico-químicos (pH, cor, TBA) foram avaliados a fim de verificar diminuição da carga microbiológica e possíveis alterações de pH, cor do filé, e oxidação lipídica (TBA). A concentração de ozônio mais efetiva sobre a diminuição da carga microbiana da superfície da tilápia foi a de 1,5 ppm, reduzindo as populações inicias de bactérias mesófilas em 91,78%. Nesta concentração (1,5 ppm), a eficácia foi nos primeiros 5 min., reduzindo a carga microbiana em 71,23%. Na imersão do filé, a concentração de ozônio de 1,5 ppm também apresentou a maior redução de bactérias mesófilas 70,19%. O tratamento dos filés com água ozonizada não demonstrou influência sobre o pH e cor dos filés, no entanto, observou-se um aumento dos valores de TBA (1,5 ppm de O3 por 15 min.), demonstrando que ocorreu oxidação lipídica, mas inferior aos limites que os deixam impróprios para o consumo. Os resultados demonstraram que a água ozonizada foi eficiente na redução da carga microbiana do pescado durante o processamento. O custo do consumo de energia elétrica utilizada para geração do ozônio demostrou sua viabilidade de uso
2017-09-01

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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
In Brazil, it is considered that the annual production of tilapias overcomes 100 thousand tons, mainly due to the productive potential of the Northeast area that answered for 41% of the total production of 70.000 tons in 2004, generating income of US$ 200.000.000,00, due to your climatic conditions, technology readiness and consumption market, regional and national in expansion. The intensification of cultivations has as consequence the increase of organic matter, that it favors the multiplication of microorganisms, making possible him/it supplies of diseases in the occurrence of adverse situations to the fish. Tilapia (Oerochromis niloticus) of cultivations of the state of Pernambuco they were appraised with objective of determining the frequency of bacterial diseases. For so much, samples of several farms were analyzed, in the several aspects, with relevance for the bacterial agents. The tilapia were examined with relationship to the streptococcus presence, víbrios, coliform, pseudomonas and aeromonas. Clinical exams and autopsy were accomplished, for microscopic analysis of the lesions and better definition of the probable agent etiological. The analyses were accomplished at the Laboratory of Sanity of Aquatic Animals (LASAq) of the Rural Federal University of Pernambuco (UFRPE) and in the Center of Development and Diffusion of Technology in Aquaculture of the State University of Bahia (UNEB). The principal pathological agents were víbrios and aeromonas, that are pathogens responsible opportunists for significant losses, being identified the following species in 46 isolated: V. natriegens (1/46), V. metschnikovii (2/46), V. halioticoli (1/46), V. fischeri (2/46), V. mimicus (23/46), V. diabolicus (1/46), V. furnissi (1/46), V. cholerae o1 (1/46), V. scophthalmi (4/46), V. proteolyticus (3/46), V. argarivorans (1/46), V. ordalii (2/46) and Vibrio spp. ( 3/46). The isolated vibrios presented larger sensibility to the antimicrobianos enrofloxacina (100%) and florfenicol (98,18%) and in decreasing order, gentamicina (90,91%), cotrimoxazol (sulfametoxazol+trimetroprim) (76,36%), tetraciclin (67,27%), eritromicin (30,91%) and amoxilina (3,64%). The isolated ones tested they came 100% resistant the penicillin. In this study, 96,4% (53/55) of the víbrios they presented index multiple resistance to antibiotics (MAR), superior to 0,22, characterizing multiple resistance. In 35 isolated the identified aeromonas were: A.caviae (1/35), A. shubertii (11/35), A. media (4/35), A. popoffii (1/35), A. sobria (3/35), A. encheleia (4/35), A. veronii (4/35) e A. jandaei (4/35) Forty were tested isolated of aeromonas with relationship to the sensibility to 08 antimicrobial, of these they showed larger sensibility the florfenicol (100,0%), enrofloxacina(95,0%), gentamicina (95,0%) and in decreasing order, cotrimoxazol (sulfametoxazol+trimetroprima) (67,5%), tetraciclina (65,0%). There was smaller sensibility the eritromicina (20,0%), penicillin (5,0%) and the amoxilina (2,5%), confirming the resistance existence. The index of multiple resistance to antibiotics (MAR) for the isolated of aeromonas it varied in an interval from 0,12 to 0,62, of these 95% (38/40) they came superior to 0,22 characterizing multiple resistance. Most of the species of isolated víbrios is not considered pathogenic for the fish (environmental), but nevertheless they can represent risk for the health of the tilapia for subject of opportunism and of the consumer, mainly if consumed raw. The isolated and identified movable aeromonas in this study are commonly considered as environmental, however many of the analyzed fish presented compatible symptomatology with the illness caused by these agents opportunists.
No Brasil, estima-se que a produção anual de tilápias supere 100 mil toneladas, principalmente devido ao potencial produtivo da região Nordeste que em 2004 respondeu por 41 % da produção total de 70.000 toneladas, gerando renda de US$ 200.000.000,00, decorrente de suas condições climáticas, disponibilidade de tecnologia e mercado de consumo, regional e nacional em expansão. A intensificação de cultivos tem como conseqüência o aumento de matéria orgânica, que favorece a multiplicação de microrganismos, possibilitando o surto de doenças na ocorrência de situações adversas aos peixes. Tilápias (Oerochromis niloticus) de cultivos do estado de Pernambuco foram avaliadas com objetivo de determinar a freqüência de doenças bacterianas. Para tanto, analisaram-se amostras de diversas fazendas, nos diversos aspectos, com relevância para os agentes bacterianos. As tilápias foram examinadas quanto à presença de estreptococos, víbrios, coliformes, pseudomonas e aeromonas. Foram realizados exames clínicos e necropsias, para análise microscópica das lesões e melhor definição do provável agente etiológico. As análises foram realizadas no Laboratório de Sanidade de Animais Aquáticos (LASAq) da Universidade Federal Rural de Pernambuco (UFRPE) e no Centro de Desenvolvimento e Difusão de Tecnologia em Aqüicultura da Universidade Estadual da Bahia (UNEB). Os principais agentes patológicos foram víbrios e aeromonas, que são patógenos oportunistas responsáveis por perdas significantes, sendo identificadas as seguintes espécies em 46 isolados: Vibrio natriegens (1/46), V. metschnikovii (2/46), V. halioticoli (1/46), V. fischeri (2/46), V. mimicus (23/46), V. diabolicus (1/46), V. furnissi (1/46), V. cholerae O1 (1/46), V. scophthalmi (4/46), V. proteolyticus (3/46), V. argarivorans (1/46), V. ordalii (2/46) e Vibrio spp.(3/46). Os vibrios isolados apresentaram maior sensibilidade aos antimicrobianos enrofloxacina (100%) e florfenicol (98,18%) e em ordem decrescente, gentamicina (90,91%), cotrimoxazol (sulfametoxazol+trimetroprima) (76,36%), tetraciclina (67,27%), eritromicina (30,91%) e amoxilina (3,64%). Os isolados testados apresentaram-se 100% resistentes a penicilina. Neste estudo, 96,4% (53/55) dos víbrios apresentaram índice múltipla resistência a antibióticos (MAR), superior a 0,22, caracterizando múltipla resistência. Em 35 isolados as aeromonas identificadas foram: Aeromonas caviae (1/35), A. shubertii (11/35), A. media (4/35), A. popoffii (1/35), A. sobria (3/35), A. encheleia (4/35), A. veronii (4/35) e A. jandaei (4/35). Foram testados 40 isolados de aeromonas quanto à sensibilidade a oito antimicrobianos, tendo mostrado maior sensibilidade a florfenicol (100,0%), enrofloxacina(95,0%), gentamicina (95,0%), cotrimoxazol (sulfametoxazol+trimetroprima) (67,5%), tetraciclina (65,0%). Houve menor sensibilidade a eritromicina (20,0%), penicilina (5,0%) e a amoxilina (2,5%), confirmando a existência de resistência. O índice MAR para os isolados de aeromonas variou de 0,12 a 0,62, dos quais 95% (38/40) apresentaram índices superiores a 0,22, caracterizando multiresistência. A maioria das espécies de víbrios isoladas não é considerada patogênica para os peixes (ambientais), mas ainda assim podem representar risco para a saúde das tilápias por questão de oportunismo e do consumidor, principalmente se consumido cru. As aeromonas móveis isoladas e identificadas neste estudo são comumente consideradas como ambientais, porém muitos dos peixes analisados apresentaram sintomatologia compatível com a enfermidade causada por estes agentes oportunistas.

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior
Nile tilapia, Oreochromis niloticus (Linnaeus, 1758), is one of the most cultivated species in our country. The fish processing industries generate large amounts of waste. In the tilapia processing waste materials represent more than 60%. Collagen is the main protein of connective tissue and is the most abundant protein in mammals, birds and fish. A commercial use of the collagen is gelatin, obtained by partial hydrolysis of collagen. Edible coatings and films are types of protection that can be applied in a food. The proteins are among the major macromolecules found in edible films. Seafood is very susceptible to deterioration process mainly because there are some specific factors. Any skin as mechanically separated meat residues (CMS) tilapia have been used for the extraction of gelatin, as well the scale was also used for this allocation. Closing a production cycle with the full use of fish and product innovation. The objective of this work is to extract gelatin from the scales of Nile tilapia (Oreochromis niloticus) and applied as a coating on cold fish fillet to evaluate their performance as the deterioration process. For the extraction of gelatin were performed essentially five steps (demineralization, acid and alkali treatments alternately and extraction in distilled water under heating). The extracted gelatin was characterized as the chemical composition, minerals, water activity (Aw), pH, gel strength, color, extraction yield, differential scanning calorimetry (DSC), thermogravimetric (TGA), infrared spectroscopy (FTIR) and electrophoresis. We were prepared two coating solutions of gelatin (1% and 1.5%) both with 0.2% (v / v) glycerol. The steaks were subjected to spray application of coating solution, placed in plastic bags and stored in refrigerator at temperature 2.6 Â C Â 0.8 for 18 days. Physical and chemical analysis (Determination of pH, volatile nitrogenous bases (TVB-N), Determination of reactive substances tiobabitÃrico acid) and microbiological (psychrotrophic bacteria) of fillets coated every three days during the 18 days of storage . The extraction of gelatin from this residue may be a new alternative, since it presents a favorable caracterisiticas gelatin quality, mainly due to good gel strength (461.640 g); low water activity (Aw 0.461); Low moisture and ash content (15.16% and 5.39%, respectively), high protein content (86.86%); next to the white color (L =; 88.711; a = -0.295 b = 2.851) and good thermal properties for uses up to 200 Â C. The application of gelatin as coating tilapia fillet to a possible inhibition in the deterioration process not proved to be completely effective. This result can probably be attributed to initial quality of the fillet which showed initial bacterial count of 6.0 log CFU / g.
A tilÃpia do Nilo, Oreochromis niloticus (LINNAEUS,1758), à uma das espÃcies mais cultivadas no nosso paÃs. As indÃstrias de beneficiamento de pescado geram grandes quantidades de resÃduos. No beneficiamento de tilÃpias seus resÃduos representam mais de 60%. O colÃgeno à a principal proteÃna do tecido conjuntivo, sendo a proteÃna mais abundante em mamÃferos, aves e peixes. Uma utilizaÃÃo comercial do colÃgeno à a gelatina, obtida pela hidrÃlise parcial do colÃgeno. Revestimentos e filmes comestÃveis sÃo tipos de proteÃÃo que podem ser aplicadas em um alimento. As proteÃnas estÃo entre as principais macromolÃculas encontradas em filmes comestÃveis. O pescado à muito susceptÃvel ao processo de deterioraÃÃo principalmente devido hà alguns fatores prÃprios. Tanto a pele como o resÃduo de carne mecanicamente separada (CMS) de tilÃpia jà foram utilizados para a extraÃÃo de gelatina, assim a escama tambÃm foi utilizada para essa destinaÃÃo. Fechando um ciclo de produÃÃo com o aproveitamento integral do pescado e inovaÃÃo de produtos. O objetivo desse trabalho à extrair gelatina a partir das escamas de tilÃpia do Nilo (Oreochromis niloticus) e aplicar como revestimento em filà de peixe resfriado para avaliar seu desempenho quanto ao processo de deterioraÃÃo. Para a extraÃÃo da gelatina foram realizadas basicamente cinco etapas (desmineralizaÃÃo, tratamentos Ãcidos e alcalinos alternadamente e extraÃÃo em Ãgua destilada sob aquecimento). A gelatina extraÃda foi caracterizada quanto a composiÃÃo centesimal, minerais, atividade de Ãgua (Aw), pH, forÃa de gel, cor, rendimento de extraÃÃo, calorimetria diferencial de varredura (DSC), termogravimÃtrica (TGA), espectroscopia no infravermelho (FTIR) e eletroforese. Foram preparadas duas soluÃÃes de revestimento a base de gelatina (1% e 1,5%), ambas com 0,2% (v/v) de glicerol. Os filÃs foram submetidos à aplicaÃÃo da soluÃÃo de revestimento por aspersÃo, acondicionados em sacos plÃsticos e armazenados em refrigerador a temperatura 2,6ÂC  0,8 durante 18 dias. Foram realizadas anÃlises fÃsico-quÃmicas (DeterminaÃÃo do pH, Bases nitrogenadas volÃteis totais (BVT-N), DeterminaÃÃo de substÃncias reativas ao Ãcido tiobabitÃrico) e microbiolÃgicas (bactÃrias psicrotrÃficas) dos filÃs revestido a cada trÃs dias durante o perÃodo de 18 dias de armazenamento. A extraÃÃo de gelatina a partir desse resÃduo pode ser uma nova alternativa, jà que a mesma apresenta caracterisiticas favorÃveis a uma gelatina de boa qualidade, principalmente devido a boa forÃa de gel (461,640 g); baixa atividade de Ãgua (Aw 0,461); Baixos teores de umidade e cinzas (15,16% e 5,39%, respectivamente), alto teor de proteÃnas (86,86%); cor prÃxima ao branco (L =;88,711; a= -0,295; b= 2,851) e boas propriedades tÃrmicas para usos atà 200ÂC. A aplicaÃÃo da gelatina como revestimento em filà de tilÃpia para uma possÃvel inibiÃÃo no processo de deterioraÃÃo nÃo mostrou-se completamente efetiva. Esse resultado provavelmente pode-se atribuir a qualidade inicial do filà que apresentou contagem bacteriana inicial de 6,0 log UFC/g.