Detection and quantitative analysis of polychlorinated biphenyls in tilapia from Hawaiian waters

The purpose of this study was to investigate polychlorinated biphenyls (PCBs) contamination in tilapia (Oreochromis mossambicus) collected from the Manna stream and Ala Wai Canal of O'ahu, an island of the geographically isolated Hawaiian archipelago. Our results show that the average concentrations of PCBs varied from 51.90 to 89.42 ng g(-1) lipid weight for the sampling sites. Relative toxic potencies (RTPs) and toxic equivalencies (TEQs) were determined to be 20.38-40.60 ng TCDD g(-1) lipid weight and 2.89-4.17 ng TEQ g(-1) lipid weight by 7-ethoxy-resorufin-O-deethylase (EROD) activity analysis and calculation of PCB concentrations based on toxic equivalency factors (TEFs), respectively. Penta-chlorinated congeners were found to be predominant, which revealed that Aroclor 1254 was a possible major source of PCBs in our fish samples. PCB 118, an indicator PCBs, constituted more than 55% and 30% of the total PCBs and TEQs, respectively. In addition, PCB 118 was found to have a linear correlation to the total PCBs (R = 0.975) and TEQs (R = 0.782). Detection of concentrated PCBs in Hawaiian waters suggests a potentially adverse impact of this pollutant on human health, as well as ecological systems, and suggests the necessity of environmental monitoring and hazard assessment of PCBs within the Hawaiian Islands. (c) 2008 Published by Elsevier Ltd.

Characterization of muscle-regulatory gene, MyoD, from flounder (Paralichthys olivaceus) and analysis of its expression patterns during embryogenesis

Specification and differentiation of skeletal muscle cells are driven by the activity of genes encoding members of the myogenic regulatory factors (MRFs). In vertebrates, the MRF family includes MyoD, Myf5, myogenin, and MRF4. The MRFs are capable of converting a variety of nonmuscle cells into myoblasts and myotubes. To better understand their roles in fish muscle development, we isolated the MyoD gene from flounder (Paralichthys olivaceus) and analyzed its structure and patterns of expression. Sequence analysis showed that flounder MyoD shared a structure similar to that of vertebrate MRFs with three exons and two introns, and its protein contained a highly conserved basic helix-loop-helix domain (bHLH). Comparison of sequences revealed that flounder MyoD was highly conserved with other fish MyoD genes. Sequence alignment and phylogenetic analysis indicated that flounder MyoD, seabream (Sparus aurata) MyoD1, takifugu (Takifugu rubripes) MyoD, and tilapia (Oreochromis aureus) MyoD were more likely to be homologous genes. Flounder MyoD expression was first detected as two rows of presomitic cells in the segmental plate. From somitogenesis, MyoD transcripts were present in the adaxial cells that give rise to slow muscles and the lateral somitic cells that give rise to fast muscles. After 30 somites formed, MyoD expression decreased in the somites except the caudal somites, coincident with somite maturation. In the hatching stage, MyoD was expressed in other muscle cells and caudal somites. It was detected only in muscle in the growing fish.

评价水产动物生长性能的生理生化指标和分子生物学指标

以奥利亚罗非鱼(Oreochromis aureus)为实验对象，设计了3种不同的摄食类型，分别是鲜活饵料组、饥饿3周后饱食投喂组和人工饲料组。鲜活饵料组投喂冰冻赤子爱胜蚓，利用蚯蚓体内丰富的营养成分和活性物质，以期获得奥利亚罗非鱼良好的生长状况；饥饿后饱食组是指饥饿3周后，以人工饲料饱食投喂2周，用于研究饥饿与补偿生长获得快速生长时血液理化指标的变化情况；人工饲料组作为对照组。纯淡水条件下养殖，水温25±2℃。测定了奥利亚罗非鱼在3种摄食类型饲喂下某些血液生理生化指标变化的情况，并将指标变化情况与增重率做相关性分析，试图找出能够反映奥利亚罗非鱼生长性能的血液生理生化指标。 研究结果表明，奥利亚罗非鱼在饥饿3周后获得了补偿生长，补偿生长时的增重率和特定生长率显著高于人工饲料组(P<0.05)，高于鲜活饵料组，但差别不显著；相关性分析研究表明血清总蛋白、胆固醇、四碘甲状腺原氨酸（T4）与增重率极显著相关(P<0.01)，血红蛋白显著相关(P<0.05)，红细胞、白细胞、碱性磷酸酶高度相关(相关系数为0.580、0.551和0.557)，因此，建议血清总蛋白、胆固醇和血红蛋白可作为能够反映罗非鱼生长性能的新指标。 根据序列设计引物，PCR反应条件：变性温度：95 ℃，3 min；退火温度：57℃，20 sec；延伸温度：72℃，5 min，共36个循环，从牙鲆、黑鲪和鲈鱼中克隆出胰岛素样生长因子（IGF-Ⅰ）部分序列，首次证实了IGF-Ⅰ在3种海水鱼中的存在。 利用蛋氨酸与ZnSO4•7H2O，在pH 5.5、80℃下，反应1小时，采用蛋氨酸与硫酸锌2：1的配料比，合成出了产物蛋氨酸螯合锌，蛋氨酸螯合锌外观白色，粉状，室温下微溶于水，不溶于乙醇，并用原子吸收光谱法测定其含锌量为15%，螯合率为88.2%。

Identity of a Tilapia Pheromone Released by Dominant Males that Primes Females for Reproduction

Knowledge of the chemical identity and role of urinary pheromones in fish is scarce, yet it is necessary in order to understand the integration of multiple senses in adaptive responses and the evolution of chemical communication [1]. In nature, Mozambique tilapia (Oreochromis mossambicus) males form hierarchies, and females mate preferentially with dominant territorial males, which they visit in aggregations or leks [2]. Dominant males have thicker urinary bladder muscular walls than subordinates or females and store large volumes of urine, which they release at increased frequency in the presence of subordinate males or preovulatory, but not postspawned, females [3–5]. Females exposed to dominant-male urine augment their release of the oocyte maturation-inducing steroid 17α,20β-dihydroxypregn-4-en-3-one (17,20β-P) [6]. Here we isolate and identify a male Mozambique tilapia urinary sex pheromone as two epimeric (20α- and 20β-) pregnanetriol 3-glucuronates. We show that both males and females have high olfactory sensitivity to the two steroids, which cross-adapt upon stimulation. Females exposed to both steroids show a rapid, 10-fold increase in production of 17,20β-P. Thus, the identified urinary steroids prime the female endocrine system to accelerate oocyte maturation and possibly promote spawning synchrony. Tilapia are globally important as a food source but are also invasive species, with devastating impact on local freshwater ecosystems [7, 8]. Identifying the chemical cues that mediate reproduction may lead to the development of tools for population control [9–11].

Endocrine regulation of extracellular matrix proteins in calcified tissue in teleost fish

Tese dout., Biologia, Universidade do Algarve, 2005

The social brain : how social stimuli are translated into neuroendocrine signals

Tese de doutoramento, Biologia (Ecofisiologia), Universidade de Lisboa, Faculdade de Ciências, 2014

The combined effect of copper and low pH on antioxidant defenses and biochemical parameters in neotropical fish pacu, Piaractus mesopotamicus (Holmberg, 1887)

Copper sulfate is widely used in aquaculture. Exposure to this compound can be harmful to fish, resulting in oxidative metabolism alterations and gill tissue damage. Pacu, Piaractus mesopotamicus, (wt = 43.4 +/- A 3.35 g) were distributed in experimental tanks (n = 10; 180 l) and exposed for 48 h to control (without copper addition), 0.4Cu (0.4 mg l(-1)), 0CupH (without copper addition, pH = 5.0) and 0.4CupH (0.4 mg l(-1), pH = 5.0). In liver and red muscle, the superoxide dismutase (SOD) was responsive to the increases in the aquatic copper. The plasmatic intermediary metabolites and hematological variables in the fish of group 0.4Cu were similar to those of the control group. Conversely, the exposure to 0.4CupH caused an increase in the plasmatic lactate, number of red blood cells (RBC) and hemoglobin (Hb). Plasmatic copper concentration [Cu(p)] increased in group 0.4Cu and 0.4CupH, which is higher in group 0.4CupH, suggests an effect of water pH on the absorbed copper. Exposure to 0.4Cu and 0.4CupH resulted in a reduction in the Na(+)/K(+)-ATPase activity and an increase in metallothionein (MT) in the gills. Exposure to 0CupH caused a decrease in glucose and pyruvate concentrations and an increase in RBC, Hb, and the branchial Na(+)/K(+)-ATPase activity. These responses suggest that the fish triggered mechanisms to revert the blood acidosis, save energy and increase the oxygen uptake. MT was an effective biomarker, responding to copper in different pHs and dissolved oxygen. Combined-factors caused more significant disturbance in the biomarkers than single-factors.

Diversidade Ictiofaunística e Ecologia reprodutiva de uma espécie nativa de peixe da Bacia Piranhas-Assu, RN

The Caatinga biome is rich in endemic fish species fauna. The present study the results of fish faunal surveys conducted in the hydrographic basin of Piranhas-Assu of the Brazilian Caatinga biome. The fish samples collected were distributed in four orders (Characiformes, Perciformes, Siluriformes and Synbranchiformes), 11 families (Characidae, Curimatidae, Auchenipteridae, Anostomidae, Prochilodontidae, Erythrinidae, Cichlidae, Sciaenidae, Heptapteridae, Loricariidae, Synbranchidae) and 22 species, of which 17 are endemic and five have been introduced from other basins. The order Characiformes was the most representative in number of species (46,35% ) followed by Perciformes (35,38%), Siluriformes (17,44%) and Synbranchiformes (0,5%). The Nile tilapia, Oreochomis niloticus, the only exotic species, was most expressive in number of individuals (24.92%) followed by the native species piau preto, Leporinus piau (18,77 %). Considering the relative frequency of occurrence of the 22 species, 13 were constant, five were accessory and four were occasional. This study investigated the reproductive ecology of an endemic fish black piau, Leporinus piau from the Marechal Dutra reservoir, Acari, Rio Grande do Norte. Samplings were done on a monthly basis from January to December 2009, and a total of 211 specimens were captured. The environmental parameters such as rainfall, temperature, pH, electrical conductivity and dissolved oxygen of water were recorded. The sampled population showed a slight predominance of males (55%), however females were larger and heavier. Both sexes of L. piau showed positive allometric growth, indicating a higher increase of weight than length. The first sexual maturation of males occurred at smaller size, with 16.5 cm in total length than females (20.5 cm). During the reproductive period, the condition factor and gonadosomatic index (GSI) of L. piau were negatively correlated. This species has large oocytes with a high mean fecundity of 54.966 with synchronous oocyte development and total spawning

Testes físico-mecânicos e físico-químicos do couro da tilápia vermelha

Realizaram-se testes físico-mecânicos e físico-químicos em couro de tilápia vermelha (Oreochromis spp.) a fim de testar a sua resistência. As amostras foram distribuídas em delineamento inteiramente ao acaso com dois tratamentos: no T1, procedeu-se à retirada do corpo-de-prova no sentido longitudinal e, no T2, à retirada do corpo-de-prova no sentido transversal. Para os testes de determinação da resistência à tração, alongamento e rasgamento progressivo, foi utilizado o dinamômetro EMIC, com velocidade de afastamento entre as cargas de 100 ± 20mm/min, em ambiente climatizado (± 23ºC e UR do ar de 50%), por 24 horas. A espessura do couro variou de 0,61 a 0,75mm, mas não houve diferença entre os sentidos analisados. O couro apresentou maior resistência à tração no sentido transversal, 25,89N/mm², (P<0,01), comparado ao sentido longitudinal, 14,20 N/mm². O alongamento foi significativamente (P<0,05) maior no sentido longitudinal, 80,8%, em relação ao transversal, 62,6%. Não houve diferença para o rasgamento progressivo entre os tratamentos. O couro apresentou teor de óxido de cromo de 3,8%, graxa de 15,1% e pH e cifra diferencial de 3,5 e 0,5, respectivamente. Os valores nos testes de resistência e físico-químicos apresentados pelo couro indicam que ele pode ser utilizado para a confecção de vestuário e artefatos de couro em geral.

Relação hepatosomática e esplenosomática em peixes teleósteos de cultivo intensivo

The mean values of hepatosomatic relation (HSR), splenosomatic relation (SSR) and relative condition factor (Kn) in Nile tilapia (Oreochromis nilolicus Trewavas, 1983); pacu (Piaractus mesopolamicus Holmberg, 1887); piauçu (Lepori-nus macrocephalus Garavello & Britski, 1988) and tambacu hybrid (P. mesopotamicus male x Colossoma macropomum Cuvier, 1818 female) are described. The experiment was carried out from feefishing farm situated in Franca, São Paulo State, Brazil. Nile tilapia showed the greatest HSR compared to pacu, piauçu and tambacu. Although, in the last three fishes the relation was similar. The SSR between tilapia and piausu was similar, but smaller than observed in pacu and tambacu. Nevertheless, SSR in pacu and tambacu was different. The hepatic weight/body weigth relation and hepatic weight/body length relation presented positive correlation in ali studied fishes. The splenic weight/body weigth relation and splenic weight/body length relation were not significam (P>0.05) in Nile tilapia, pacu and tambacu, but highly significant in piauçu (PO.01).

Chromosome Evolution in African Cichlid Fish: Contributions from the Physical Mapping of Repeated DNAs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Monitoramento de características físico-químicas da água e taxas de sedimentação de tripton no Córrego da Arribada (Baixo Tietê-SP) relacionadas à piscicultura em tanques-rede

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Influência da adição in vivo de vitamina E e de métodos de abate nos atributos de qualidade de filés de tilápia

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Tilapicultura em ecossistemas aquáticos abertos: desenvolvimento sustentável ou degradação ambiental ? Estudo de caso em represa oligotrófica

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Suplementação de zinco em dietas: desempenho produtivo e resposta hemática e imunológica da tilápia-do-nilo submetida a desafio bacteriano

Pós-graduação em Zootecnia - FMVZ