Avaliaram-se os efeitos da administração do extrato seco de maracujá (Passiflora incarnata), veiculado na dieta, sobre a morfologia dos hepatócitos de juvenis de tilápias do Nilo (Oreochromis niloticus). Peixes isolados (86,50 &plusmn; 10,17 g) receberam durante 28 dias ração comercial extrusada (32% PB - 2% biomassa) contendo o extrato diluído em alginato de sódio nas doses 0 (controle), 50, 100 e 200 mg/Kg, (n = 6 peixes/tratamento), registrando-se diariamente o consumo. No início e ao final do experimento cada indivíduo foi exposto (30 minutos) à reflexão da própria imagem em espelho (presença virtual de um coespecífico - estresse social), sendo a seguir anestesiado (2-fenoxietanol 0,5 mL/L) para realização de biometria e coleta de sangue (veia caudal) para determinação dos níveis plasmáticos de glicose e cortisol. Após 28 dias todos os animais foram sacrificados para remoção do fígado e obtenção de fragmentos utilizados na contagem de células e avaliação da morfometria do citoplasma dos hepatócitos (H/E), observando-se também as reservas de glicogênio hepático (PAS). Visando a comparação dos efeitos do estresse social natural com aquele empregado no experimento, seis peixes provenientes de um grupo de 30 indivíduos foram também sacrificados e utilizados como referência (valores basais) para avaliação dos parâmetros histológicos. Os dados foram submetidos a ANOVA, utilizando-se o proc mixed SAS 8.0 (p<0,05) para os parâmetros consumo de alimento, ganho em peso e bioquímica sangüínea (cortisol e glicose) e GLM SAS 8.0 (p<0,01) para a contagem de células e morfometria dos hepatócitos. Verificou-se que os pesos e os comprimentos iniciais não diferiram, que o consumo de alimento não foi alterado pela adição do extrato e que todos os peixes, independentemente do tratamento, cresceram significativamente. Os níveis de cortisol e de glicose também não diferiram inicialmente entre os grupos e não foram alterados pela presença do agente ou pela adição do extrato. Porém, observou-se um aumento significativo da glicose e redução dos níveis de cortisol em todos os peixes. A adição do extrato nas diferentes doses provocou aumento crescente e significativo da área citoplasmática e redução do número de células em todos os animais, com destaque para a dose 100 mg/Kg. O mesmo não ocorreu nos peixes do grupo controle, cujas áreas citoplasmáticas foram significativamente menores, em decorrência de um menor acúmulo de glicogênio hepático. Embora os efeitos do agente estressor empregado não tenham sido detectados pela análise dos parâmetros bioquímicos sangüíneos, verificou-se que este procedimento provocou alterações metabólicas que contribuíram para a depleção dos estoques de glicogênio no fígado. Este efeito parece ter sido revertido nos peixes que receberam a dieta contendo o extrato de maracujá que, por meio de mecanismos não elucidados neste trabalho, contribuiu para a manutenção ou aumento dos estoques de glicogênio hepático. Concluiu-se que o extrato de maracujá veiculado na dieta, na dose de 100 mg/Kg, protege juvenis de tilápia da depleção dos estoques de glicogênio hepático causada pelo estresse social. / Effects of Passion fruit (Passiflora incarnata) dry extract administration on hepatocyte morphometry of juveniles Nile tilapias (Oreochromis niloticus) were investigated. Male isolated fish (86,50 &plusmn; 10,17 g) were daily fed (28 days) with extruded commercial ration (32% crude protein - 2% biomass) containing the extract diluted in sodium alginate in graded doses 0 (control), 50, 100 and 200 mg/Kg (n= 6 animals/treatment), registering daily consumption. At the start and after 28 days of experiment each fish was displayed to the reflection of own mirror image (30 minutes) in order to simulate the virtual presence of a coespecific (social stress). Then the animals were anesthetized (2-fenoxietanol) for biometric measures and blood collection (caudal vein) for determination of the plasmatic levels of glucose and cortisol. After 28 days the animals were sacrificed for removal of liver fragments samples used to histological examination (cytoplasmic area and number of cells - HE stained; hepatic glycogen supplies - PAS stained). Aiming the comparison of the natural social stress with that utilized in this experiment, six fish from a group of 30 individuals were also sacrificed and used as reference (basal values) for the histological parameters evaluation. Food consumption, weight gain and sanguine biochemist parameters (cortisol and glucose) were submitted to ANOVA, SAS 8.0 proc mixed (p<0,05) and data of cells counting and hepatocyte morfometry to the same test, using SAS 8.0 GLM (p<0,01). The initial weights and lengths were similar, the food consumption was not modified by the addition of the extract and all the fish grew significantly during the experiment. Initial levels of cortisol and glucose were also similar between groups and did not modify by the stressor agent or treatments with the extract. However, a significant increase of glucose and reduction of cortisol levels were observed for all the fish. The addition of different extract doses provoked significant and noticeable increase of the cytoplasmic area and reduction of the cells number, mainly for 100 mg/Kg dose. In the control group cytoplasmatic area was significantly minor due to lesser hepatic glycogen accumulation. The stressor agent did not affect sanguine biochemists parameters but seems to lead metabolic alterations that had collaborated with the depletion of liver glycogen supplies. This effect seems to have been reverted in the fish that received the diet contend Passion fruit extract that, by means of a mechanism not elucidated in this experiment, contributed for the maintenance or increase of hepatic glycogen supplies. It was conclude that Passion fruit extract diet inclusion at 100 mg/Kg dose protects the tilapia against the hepatic glycogen depletion caused by social stress.

Este estudo teve por objetivos conhecer aspectos da toxicidade de Cu e Cd, separadamente e em combinacao (Cu+Cd) em tilapias (Oreochromis niloticus), verificando possiveis efeitos sinergicos ou antagonicos. Determinou-se nessas situacoes, a bioacumulacao dos metais no tecido muscular, branquias e figado dos especimes, enfase ao potencial bioindicador da especie. Para tanto, ensaios de toxicidade aguda na forma estatica foram conduzidos por um periodo de 96 horas. Previamente a esses, foram realizados testes preliminares com as referidas especies quimicas em concentracoes logaritmicas, com o intuito de se determinar os intervalos onde 100% de mortalidade e 100% de sobrevivencia eram observados para a especie. Atraves desta etapa estabeleceram-se para os ensaios de toxicidade aguda, as concentracoes de 0,0, 0,5, 1,0, 2,5, 5,0 e 10,0 mg L-1 para Cu e Cu+Cd e de 0,0, 1,0, 5,0, 10,0, 25,0 e 50,0 mg L-1 para Cd. As variaveis temperatura, pH, amonia, oxigenio dissolvido e metais dissolvidos foram aferidas no inicio e a cada 24 horas. A dureza total foi monitorada apenas para os tratamentos controle, no inicio e termino dos experimentos para fins de verificar a qualidade da agua. Para os ensaios cronicos, conduzidos na forma semi-estatica e com duracao de 21 dias, duas concentracoes de cada metal foram utilizadas, onde o criterio de estabelecimento dos valores foi a CL50/10 e a media dos logaritmos das CL50/10 e CL50/100. Amostragens para verificacao da bioacumulacao foram realizadas em 24 e 96 horas, 07, 14 e 21 dias, sendo que durante essas amostragens, as variaveis pH, temperatura, oxigenio dissolvido, amonia e teores de metais nas solucoes foram determinadas. Como nos ensaios anteriores, a dureza total foi determinada no primeiro e ultimo dia para controle de qualidade da agua. As CL50-96h para o cobre, cadmio e cobre+cadmio foram respectivamente 3,53 mg L-1, 20,13 mg L-1 e 1,36 mg L-1 Pode-se observar durante os ensaios preliminar e agudo, uma acentuada precipitacao do Cu principalmente nas maiores concentracoes, isso em decorrencia do produto de solubilidade do hidroxido de cobre formado nas cubas experimentais. 8 Nessas concentracoes, observou-se que o Cd apresentou reducao quando em combinacao, atribuido a co-precipitacao ocorrida com o Cu. No que diz respeito a bioacumulacao dos metais nos orgaos e tecidos, pode-se observar, com algumas excecoes, que o figado, devido as suas funcoes metabolicas, apresentou uma maior acumulacao, seguido das branquias e tecido muscular. A tilapia apresentou maior resistencia ao CdCl2.H2O do que ao CuCl2 tendo a combinacao das duas especies quimicas potencializado a toxicidade de forma sinergica. Esse estudo possibilitou concluir que a afericao das concentracoes efetivas dos elementos de interesse durante ensaios de toxicidade e de relevante importancia, pois a concentracao esperada para as especies quimicas dissolvidas podem diferir daquelas esperadas, em funcao do elemento analisado e do tempo de duracao do experimento / The aim of this work was to assess for the toxicity of Cu and Cd, separately and in combination (Cu+Cd) in tilapias (Oreochromis niloticus), checking for the possible synergical or antagonic effects. In these situations, the bioaccumulation of metals in muscle tissue, gill and liver were determinated, emphasizing the potential bioindicator of the specie. Acute toxicity test in static mode were carried out for a period of 96 hours. Prior to these, preliminary tests were performed with such chemical species in logarithmic concentration, in order to establish the range of concentrations in which 100% mortality and 100% survival were observed for the specie. Through this step, concentrations of 0.0, 0.5, 1.0, 2.5, 5.0 and 10.0 mg L-1 for Cu and Cu+Cd and of 0.0, 1.0, 5.0, 10.0, 25.0 and 50.0 mgL-1 for Cd were defined in acute toxicity assays. Temperature, pH, ammonia, dissolved oxygen and dissolved metals were measured at the beginning and every 24 hours. Total hardness was monitored only for the control treatments, in the beginning and at the end of the experiments to check the water quality. Semi-static chronic assays, were conducted during 21 days, by using two concentrations of each metal. Concentrations were calculated as CL50/10 and average of logarithms of CL50/10 and CL50/100. Samplings for assessing the metals bioaccumulation were performed at 24 and 96 hours, 07, 14 and 21 days. In a mean time, pH, temperature, dissolved oxygen, ammonia and dissolved metals were also determinated. Like in previous assays, total hardness was determined in the first and in the last day. The LC50 for copper, cadmium and copper+cadmium were respectively 3.53 mg L-1, 20.13 mg L-1 and 1.36 mg L-1. A precipitation of copper hydroxide, moreover for the higher concentrations were observed in both, preliminary and acute assays. On these situations, Cd concentration was decreased when combined, assigned to the co-precipitation occurred with Cu. Liver, due to it metabolic functions, showed higher metals accumulation, followed by gills and musclular tissue. It can be concluded that tilapia showed greater resistance to CdCl2.H2O, than to CuCl2 and with the combination of the two chemical species, potentiated the toxicity of synergic form. This study also enabled to conclud that measurement of effective concentrations of the elements of interest during test of toxicity is relevant, because the concentrations obtained may differ to those expected, according to the element and the duration of the experiment

Les ressources génétiques naturelles du Tilapia du Nil (Oreochromis niloticus) se trouvent en Afrique. Ces ressources sont menacées en raison de modifications des habitats naturels des poissons et des introductions incontrôlées d'espèces ou de souches exotiques. Les populations de tilapia du Nil qui vivent dans des habitats extrêmes sont emblématiques de cette situation. Elles représentent des ressources génétiques originales et potentiellement utiles pour l'aquaculture. Cependant, les populations sont menacées soit par des modifications fortes de l'environnement soit par l'introduction d'espèces exotiques dans leur habitat. La caractérisation de ces populations constitue la première étape de leur protection et par conséquent leur utilisation en aquaculture. Dans notre étude, nous nous sommes concentré sur deux populations différentes de tilapia du Nil. L'une d'entre elles vit dans le lac alcalin ‘Crocodile Lake' (10 590 S / cm, pH 10) qui est un lac de cratère situé dans Central Island, au milieu du lac Turkana. La deuxième population (ou groupe de population) vit dans les sources chaudes (Hot Springs) du marais de loboi (Loboi Swamp) près du lac Bogoria au Kenya. Ces poissons vivent dans une eau caractérisée par des températures élevées, autour de 36 ° c. Toutes les populations ci-dessus (Crocodile Lake et Loboi swamp Hot Springs) ont connu ou connaissent un certain nombre de pressions sélectives de la part de leurs environnements difficiles. Pour le lac Crocodile, les poissons ont certainement dû trouver un moyen d'excréter leurs déchets azotés car à pH 10, l'excrétion n'est pas possible par simple diffusion. Pour les populations de sources chaudes, la plupart des individus devraient être des mâles car les hautes températures sont connues pour induire une masculinisation chez O. niloticus. Cette population doit avoir accumulé des mutations nécessaires pour lui permettre de surmonter les effets masculinisants des températures élevées.Pour étudier ces populations, nous avons utilisé la morphométrie géométrique et des marqueurs génétiques (microsatellites et 16 ADNmt) et nous les avons comparés à d'autres populations proches de la région. En outre, trois gènes liés au sexe (Cyp19a, Wt1b, AMH) ont été analysés en utilisant des marqueurs SNP dans trois populations de tilapia du Nil habitant les sources chaudes du marais de Loboi, et nous les avons comparés à ceux que l'on observe chez huit autres populations de l'Afrique de l'Est, la région soudano-sahélienne et éthiopiennes . Des différences morphologiques significatives ont été observées entre toutes les populations étudiées, y compris entre les trois populations voisines du marais Loboi, et entre les deux populations génétiquement liées du Crocodile Lake et du lac Turkana. Nous concluons de cette analyse que les différences morphologiques observées peuvent avoir comme origine pour une part des différences génétiques et pour une autre part des facteurs environnementaux. De même, toutes les populations étudiées sont génétiquement différenciées, et nous avons montré que les populations du marais Loboi et celle du lac Baringo ont été introgresséess par des gèes de O. leucostictus. Les analyses des gènes liés au sexe ont révélé que le gène AMH est un gène candidat pour la détermination du sexe chez le tilapia du Nil, avec 12 SNPs montrant de fortes associations avec le sexe phénotypique des individus. Néanmoins, il n'existe pas de modèle général de la détermination du sexe, il semble plutôt que les mécanismes de détermination du sexe sont différents suivant les populations de cette espèce et qu'il n'existe pas de mécanisme unique pour l'espèce entière. / Nile tilapia (Oreochromis niloticus) natural genetic resources are found in Africa. These resources are threatened due to modifications of the natural habitats of fishes and uncontrolled introductions of alien species or strains. Nile tilapia populations living in extreme habitats are emblematic of this situation. They represent original and potentially useful genetic resources for Aquaculture. However, the populations are threatened either by strong modifications or introduction of alien species in their habitats. Characterizing these populations constitutes the very first step of their protection and consequently their utilization in aquaculture. In our study we concentrated on two different populations of Nile Tilapia. One living in the alkaline Crocodile Lake (10,590 µS/cm, 10 pH) which is a Crater Lake located in the central Island of Lake Turkana. The second group of population inhabit the hot springs of Loboi Swamp near Lake Bogoria in Kenya. These fish are living in water characterized by high temperatures, around 36°c. All above populations (Crocodile Lake and Loboi Swamp Hot springs) may have experienced some selective pressures to cope with their challenging environments. For Crocodile Lake, fish may have found a way to excrete their nitrogenous wastes because at pH 10, excretion is not possible by simple diffusion. For the hot spring populations, most individuals should have been males as high temperature is known to induce masculinization in O. niloticus. This population may have accumulated adequate mutations to enable them overcome masculinizing effects of high water temperature. To study these populations we used geometric morphometrics and genetic markers (16 microsatellites and mtDNA) and compared them with other related populations from the region. In addition, three sex-linked genes (Cyp19a, Wt1b, amh) were analysed using SNP markers in three populations of Nile tilapia inhabiting hot springs of Loboi Swamp, and compared them to eight other populations from East Africa, Sudano-Sahelian and Ethiopian regions. Significant morphological differences were observed in all populations studied, including three closely related populations of Loboi Swamp, and two genetically related populations from Lake Turkana basin. Both genetic differences and environmental factors were responsible for the observed morphological differences. Similarly, all studied populations were genetically differentiated, and we demonstrated that populations from Loboi Swamp and Lake Baringo have been introgressed by O. leucostictus genes. Analyses of the sex-linked clustered revealed that amh gene is a candidate gene for sex determination in Nile tilapia, with 12 SNPs showing strong associations to phenotypic sex. Nevertheless there is no general pattern of sex determination, rather it seems that sex determination mechanisms are different with respect to populations, but is not characteristic or unique for the entire species.

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. / 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.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / This study consisted of two experiments. The first objective was to demonstrate the technical feasibility of separate BFT tank technology in juvenile cultivation of Nile tilapia, for monitoring quality variables of water and productive performance. The fish were fed different combinations of artificial food (balanced diet) and natural food (bioflocs biomass). As the supply of food decreased the tanks increased the biomass supply bioflocs. Bioflocs biomass was produced in an external tank 500 L, separately from the cultivation system (separate tank BFT). You can reduce the regular feeding rates of juvenile Nile tilapia, with artificial diets, 25 %, without losses, if bioflocs to provide wet grown animals, as a food supplement, in equal proportion. The second objective was determine the effects of the provision of dried bioflocs biomass to Nile tilapia juveniles, stocked in experimental rearing tanks for 8 weeks, upon selected variables of water quality, growth performance and effluents quality. Fish was fed with different combinations of artificial diets and bioflocs biomass, in the wet form (in natura) or dried. As the supply of artificial diet was decreased, the provision of bioflocs biomass was increased in the same proportion. The bioflocs biomass was produced in two extra 500-L tanks. The growth performance of fish that were partially fed with dried bioflocs biomass has remained below what was observed in the tanks supplied with the wet bioflocs biomass. Due to the lacking of positive results, there is not any rationale to dry the bacterial bioflocs aiming at the delivery of it as a dried biomass to the cultured fish. / O presente estudo foi constituÃdo por dois experimentos completos e consecutivos. No primeiro, objetivou-se demonstrar a viabilidade tÃcnica da tecnologia do tanque BFT (c/bioflocos) avulso no cultivo de juvenis de tilÃpia do Nilo, pelo monitoramento de variÃveis de qualidade de Ãgua e de desempenho produtivo. Os peixes foram alimentados com diferentes combinaÃÃes de alimento artificial (raÃÃo balanceada) e de alimento natural (biomassa de bioflocos). à medida que diminuÃa o aporte de raÃÃo aos tanques, aumentava o fornecimento de biomassa de bioflocos. A biomassa de bioflocos foi produzida em um tanque externo de 500 L, em separado do sistema de cultivo (tanque BFT avulso). Os tanques de cultivo que receberam aplicaÃÃes diÃrias de bioflocos apresentaram concentraÃÃes de nitrito na Ãgua significativamente menores do que as observadas nos tanques nos quais a Ãnica fonte de alimentaÃÃo dos peixes foi a raÃÃo comercial. Concluiu-se que à possÃvel reduzir as taxas regulares de arraÃoamento de juvenis de tilÃpia do Nilo, com raÃÃes artificiais, em 25%, sem prejuÃzo zootÃcnico, caso se forneÃa bioflocos Ãmidos aos animais cultivados, como suplemento alimentar, em igual proporÃÃo. O segundo experimento teve como objetivo determinar os efeitos do fornecimento de biomassa seca de bioflocos a juvenis de tilÃpia do Nilo, mantidos em tanques experimentais de cultivo por oito semanas, sobre variÃveis selecionadas de qualidade de Ãgua, desempenho zootÃcnico e qualidade de efluentes. Os peixes foram alimentados com diferentes combinaÃÃes de raÃÃo balanceada e biomassa de bioflocos, na forma Ãmida (in natura) ou seca. à medida o aporte de raÃÃo aos tanques foi menor, o fornecimento de biomassa de bioflocos foi proporcionalmente maior. A biomassa de bioflocos foi produzida em dois tanques avulsos de 500 L. O desempenho zootÃcnico dos peixes nos tanques que receberam a suplementaÃÃo de biomassa seca de bioflocos ficou abaixo do observado nos tanques com biomassa Ãmida. Pela ausÃncia de resultados positivos, concluiu-se que nÃo hà justificativa tÃcnica para a secagem dos bioflocos bacterianos com o objetivo de fornecer a biomassa seca aos peixes cultivados

Sexual differentiation is divided into gonadal sexual differentiation and brain sexual differentiation in the teleosts. Gonadal sexual differentiation is regulated by brain sexual differentiation. Brain sexual differentiation is resulted from the neural development, which lead to the sexual dimorphism of both structure and functions of brain. The neural development is influenced by the genetic factors and the external environmental factors. The lower temperature induces a higher proportion of female while the elevated temperature induces a higher proportion of male in tilapia. In addition, there is sexual difference in effects of temperature on the activity of brain neurochemicals. Water temperature plays an important role on the development of central neurotransmitter systems and sexual differentiation during the developing period. In the present study, the primary neural culture cloned from the female and male tilapia¡AOreochromis mossambicus was used. The difference of the physiological characteristics between the neural cells derived from the females and males, were investigated. These results show that the elevated temperature has an effect to enhance the proliferation in both primary neural culture of females and males.

Mémoire (M.Sc.B.)--Université du Québec à Chicoutimi, 1990. / Document électronique également accessible en format PDF. CaQCU

Made available in DSpace on 2014-06-11T19:30:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-03-17Bitstream added on 2014-06-13T19:40:11Z : No. of bitstreams: 1 favaro_egp_dr_jabo.pdf: 983800 bytes, checksum: 05601fed4d94756e0a8cf4f21dc4f9c0 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Universidade Estadual Paulista (UNESP) / O presente estudo apresenta o papel do sedimento na qualidade da água durante as estações de chuva (fluxo contínuo) e seca (fluxo não contínuo) e balanço parcial de massa do nitrogênio e fósforo nos viveiros de criação extensiva de (Oreochromis niloticus) fertilizados com resíduos de alface. No fluxo contínuo, os valores de NH4, NO2 e NO3 aumentaram (p<0,05). Similarmente, os valores da matéria orgânica, nitrogênio e fósforo no sedimento aumentaram (p<0,05). No fluxo não contínuo, os valores do PO4, clorofila-a, pH, alcalinidade e oxigênio dissolvido aumentaram (p<0,05). O fluxo contínuo da água nos meses chuvosos aumentou a carga de partículas suspensas nos viveiros, reduziu a penetração de luz e promoveu a resuspensão do sedimento e a nitrificação na coluna da água. A re-suspensão prejudicou os processos de mineralização no sedimento, contudo a nitrificação causou o aumento do NO3 e redução do NO2. A menor sedimentação das partículas limitou o desenvolvimento fitoplanctônico. O fluxo não contínuo da água nos meses secos promoveu a sedimentação das partículas suspensas e mineralização da matéria orgânica no sedimento com correspondente liberação de nutrientes para a água. Adicionalmente, a aplicação dos resíduos de alface na taxa de 0,8 kg peso seco semana-1 favoreceu os processos de mineralização no sedimento e enriquecendo a atividade microbiana. Em média, as concentrações do nitrogênio inorgânico e fósforo total foram reduzidas 48,5% e 43,7% através dos viveiros (entrada-saída)... / The role of the sediment in water quality during the rainy (continuous flow) and dry (non-continuous flow) periods and partial equilibrium of nitrogen and phosphorus mass in extensive breeding pools for tilapia (Oreochromis niloticus), manured by lettuce wastes, is provided. NH4, NO2 and NO3 rates increased (p<0.05) during the continuous flow from 119.6 μg L-1, 12.8 μg L-1 1, from 132 μg L-1 to 120.5 μg L-1 , 15.7 μg L-1 ,174 μg L-1 Organic matter, nitrogen and phosphorus rates in the sediment increased similarly (p<0.05) from 105 μg L-1, 5%, 107 μg L-1 to 108 μg L-1, 7%, 108 μg L-1. In the case of non-continuous flow, PO4, chlorophyll-a, pH, alkalinity and dissolved oxygen rates increased (p<0.05) from 166 μg L-1; 359 mg L-1; 7; 82 mg L-1 and 5 mg L-1 to 178 μg L-1; 391 mg L-1; 7; 84 mg L-1 and 5 mg L-1, respectively. Water continuous flow during the rainy months increased the number of suspended particles in the breeding pools, decreased light penetration and triggered the re-suspension of sediment and nitrification in the water column. Although re-suspension jeopardized the mineralization processes in the sediment, nitrification caused an increase in NO3 and a decrease in NO2. Less sedimentation of particles restricted phytoplankton development. Intermittent water flow during the dry months caused sedimentation of suspended particles and the mineralization of organic matter in the sediment, coupled to a corresponding release of nutrients in the water. Further, the application of lettuce wastes at the rate employed were an asset to the mineralization processes in the sediment and enriched microbial activity. Concentrations of inorganic nitrogen and total phosphorus were at an average reduced by 48.5% and by 43.7% through the breeding pools (entrance-exit), respectively. Further, 82% of Nitrogen and 48% of Phosphorus provided to the fertilizer... (Complete abstract click electronic access below)

Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-11-17T13:48:48Z No. of bitstreams: 2 eglerson_duarte.pdf: 707090 bytes, checksum: 4f4380e4c6b75fa584a38534f80e0a54 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-11-17T13:49:29Z (GMT) No. of bitstreams: 2 eglerson_duarte.pdf: 707090 bytes, checksum: 4f4380e4c6b75fa584a38534f80e0a54 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2015-11-17T13:49:29Z (GMT). No. of bitstreams: 2 eglerson_duarte.pdf: 707090 bytes, checksum: 4f4380e4c6b75fa584a38534f80e0a54 (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2011-11-25 / Funda??o de Amparo ? Pesquisa do estado de Minas Gerais (FAPEMIG) / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Banco do Nordeste do Brasil (BNB) / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Objetivou-se com esse trabalho, avaliar a propor??o ideal de concha calc?ria/brita em biofiltro, no cultivo de p?s-larvas de til?pia do Nilo. O experimento foi realizado no Laborat?rio de Aquicultura da UFVJM, entre os dias 21 de julho e 3 de agosto de 2011. P?s-larvas de til?pia do Nilo na densidade de 13,3 p?s-larvas/L foram cultivadas em aqu?rios contendo biofiltros com 100% concha calc?rias; 70% concha calc?ria/30% brita; 50% concha calc?ria/50% brita; 30% concha calc?ria/70% brita; 10% concha calc?ria/90% brita; 100% brita e como controle, aqu?rio sem biofiltro, em DIC, totalizando sete tratamentos com tr?s repeti??es. Os dados limnol?gicos e biom?tricos foram submetidos ? ANOVA e as m?dias foram comparadas pelo teste de Duncan com p?0,05. Para comparar os tratamentos que evolveram uma propor??o concha calc?ria/brita, foi feita uma an?lise de regress?o considerando n?vel de signific?ncia de 5%. Todas as concentra??es de concha calc?ria/brita apesar de n?o influenciarem nos par?metros morfol?gicos, mantiveram as condi??es da ?gua adequadas para o cultivo de til?pia do Nilo, com exce??o dos n?veis de am?nia, que em sua grande maioria, apresentaram-se acima da concentra??o recomendada para til?pias. Entretanto a n?o toxicidade aparente da am?nia, no presente trabalho, pode estar relacionada aos valores de pH, que se mantiveram pr?ximos do neutro possibilitando uma menor toxicidade do ?on am?nio. A propor??o 30% de concha calc?ria e 70% de brita ? recomendada como substrato de biofiltro, por apresentar a melhor taxa de nitrifica??o ao longo do experimento. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2011. / ABSTRACT The objective of this study was to evaluate the optimal ratio of calcareous shell /gravel in biofilter, in the cultivation of post-larvae of Nile tilapia. The experiment was conducted at the UFVJM?s Laboratory of Aquaculture, between July 21 and August 3, 2011. Post-larvae of Nile tilapia in the density of 13.3 post larvae/L were grown in aquariums containing biofilters with 100% calcareous shell, 70% calcareous shell/30% gravel, 50% calcareous shell/50% gravel, 30% calcareous shell/70% gravel, 10% calcareous shell/90% gravel and 100% gravel; and as control sample, a aquarium without biofilter in DIC, summing seven treatments with three replications. Limnological and biometric data were submitted to ANOVA and measurements were compared by Duncan test at p?0.05. To compare the treatments that have evolved a proportion of calcareous shell/gravel, there has been carried out a regression analysis considering a significance level of 5%. All concentrations of calcareous shell/gravel did not influence negatively on morphological parameters and kept water conditions suitable for the cultivation of Nile tilapia, except for the observed levels of ammonia, which were mostly above the recommended for tilapia. However, the apparent non-toxicity of ammonia in the present study may be related to pH values, which remained close to neutral allowing a lower toxicity of the ammonium ion. The proportion of 30% calcareous shell and 70% gravel substrate is recommended as biofilter for presenting the best rate of nitrification during the experiment.

Submitted by Daniela Bezerra de Amorim (amorimdaniela@outlook.com) on 2018-08-24T16:38:34Z No. of bitstreams: 1 DISSERTAÇÃO - FINAL.pdf: 1647617 bytes, checksum: 08393fe468ede9ba31a13bda1e61d582 (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-08-24T19:27:07Z (GMT) No. of bitstreams: 1 amorim_db_me_jabo.pdf: 1647617 bytes, checksum: 08393fe468ede9ba31a13bda1e61d582 (MD5) / Made available in DSpace on 2018-08-24T19:27:07Z (GMT). No. of bitstreams: 1 amorim_db_me_jabo.pdf: 1647617 bytes, checksum: 08393fe468ede9ba31a13bda1e61d582 (MD5) Previous issue date: 2018-06-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O objetivo do presente estudo foi determinado o impacto da inclusão crescente de um blend comercial de ácidos orgânicos (BAO) (0,0%, 1,0%, 2,0% e 3,0%) em três dietas contendo diferentes teores de proteína digestível (PD) (24,30%; 26,81% e 29,32%) sobre o desempenho produtivo, composição corporal, digestibilidade de nutrientes, taxa de eficiência proteica, índices fisiológicos e sobre histomorfometria intestinal de revertidos de tilápia do Nilo. Foram utilizados 468 juvenis de tilápia do Nilo, com peso médio inicial de 16,20 ± 8,03 g, distribuídos em 36 tanques. O delineamento experimental foi inteiramente casualizado com doze tratamentos e três repetições, em esquema fatorial 4x3. Os peixes foram alimentados quatro vezes ao dia até saciedade aparente por 95 dias. Não houve efeito da interação entre os teores de inclusão do BAO e os teores proteicos das dietas sobre as médias de: conversão alimentar (CA), taxa de eficiência proteica (TEP), eficiência de retenção de proteína bruta (ERPB), eficiência de retenção de energia bruta (EREB), extrato etéreo no ganho de peso (EEGP), proteína bruta no ganho de peso (PBGP), largura de vilosidades (LV), túnica muscular (TM) e sobre os índices fisiológicos. Houve efeito da interação entre os fatores estudados sobre as médias de ganho de peso (GP), consumo de ração (CR), taxa de crescimento específico (TCE), fósforo na carcaça (P) e coeficientes de digestibilidade aparente (CDAPB, CDAEB e CDAMM), sendo as maiores médias obtidas com o uso de 1% de BAO juntamente com o teor de 29,32% de PD. Para a histomorfometria intestinal, houve interação entre os fatores. As melhores médias para o número de células caliciformes (CC) e a altura das vilosidades (AV) foram obtidos nas dietas com 29,32% de PD e a inclusão de 3% do BAO. / The subject of this trial was to determine the impact of the inclusion of a commercial organic acids blend (BAO) (0.0%, 1.0%, 2.0% and 3.0%) on three diets containing different levels of digestible protein (DP) (24.30%, 26.81% and 29.32%) on the productive performance, body composition, nutrient digestibility, protein efficiency, physiological indices and intestinal histomorphometry of Nile tilapia. A total of 468 Nile tilapia juveniles were used, with initial mean weight of 16.20 ± 8.03 g, distributed in 36 tanks. The experimental design was completely randomized with twelve treatments and three replicates, in a 4x3 factorial scheme. Fish were fed four times daily until apparent satiety for 95 days. There was no effect of the interaction between the OAB inclusion levels and the protein contents of the diets on the means of: feed conversion (FC), protein efficiency rate (PER), crude protein retention efficiency (CPRE), gross energy retention efficiency (GERE), ethereal extract in weight gain (EEWG), crude protein in weight gain (CPWG), villus width (VW), muscle tunica (MT) and physiological indices. There was an effect of the interaction between the factors studied on mean weight gain (WG), feed intake (FI), specific growth rate (SGR), carcass phosphorus (P) and apparent digestibility coefficients (ADCCP, ADCGE and ADCMM). The highest means were obtained with the use of 1% OAB together with the 29.32% DP content. For intestinal histomorphometry, there was interaction between the factors. The best means for the number of goblet cells (GC) and villous height (VH) were obtained in diets with 29.32% of CP and the inclusion of 3% of OAB.