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Antecedentes: Algunos aditivos alimentarios se han vuelto en la actualidad alternativas a discrepancias tales como la búsqueda de mejores rendimientos manteniéndose dentro de los márgenes productivamente sustentables, orgánicos y ecológicos. De esta manera se incorporan nutrientes y microorganismos a la dieta como una forma alternativa de mejorar la inmunidad de los peces, aprovechando los nutrientes en el alimento y actuando positivamente en el desempeño de los animales. El objetivo del presente trabajo fue recopilar información referente al uso de aditivos inmunoestimulantes en Tilapias (Oreochromis ssp.) y su desempeño fisiológico en el organismo. Desarrollo: Muchos de estos inmunoestimulantes existentes son microorganismos o nutrientes habituales de la dieta como son los polisacáridos, proteínas o lípidos, que suministrados en concentraciones elevadas tienen la capacidad producir un efecto estimulante acelerando la resistencia a las enfermedades mediante mecanismos específicos o inespecíficos de la respuesta inmunológica, convirtiéndose en agentes primarios profilácticos. Conclusiones: El empleo de aditivos inmunoestimulantes posibilita la prevención de enfermedades comunes en el cultivo de tilapias por medio de la modulación del ambiente intestinal en las diferentes especies del género Oreochromis mejorando la respuesta inmune inespecífica y a su vez se favorecen algunos procesos tales como el crecimiento individual, la eficiencia alimenticia y la tolerancia al estrés.

Background: Some diet additives have become alternatives to achieve higher yields within the productively sustainable, organic, and ecological margins. Hence, nutrients and microorganisms can be added to the diet for fish immunity improvements, by using the nutrients in the feed, which lead to a positive animal performance. Accordingly, the aim of this paper was to gather information related to the utilization of additives as immunostimulant in tilapia (Oreochromis ssp.), and their physiological performance in the body. Development: Many of these immunostimulants are microorganisms or habitual nutrients in the diet, such as polysaccharides, proteins or lipids, which at high concentrations are capable of creating a stimulating effect, speeding disease resistance through specific or unspecific mechanisms of immunological response, thus becoming primary prophylactic agents. Conclusions: The use of additives as immunostimulants helps prevent the occurrence of common diseases in tilapia culture, by modulating the intestinal system in the different species of genus Oreochromis, thus enhancing the unspecific immune response, and, in turn, some processes like individual growth, feeding efficiency, and stress tolerance can be favored. [ABSTRACT FROM AUTHOR]

Reproduction involves multiple complex behaviours, and the effects of familiarity on such social interactions are seldom described in fish. This is particularly true for sound production and communication within aggressive or non-aggressive context. This study explores the effects of a common garden rearing without parental care of two closely related cichlid species (Nile tilapia Oreochromis niloticus and blackchinned tilapia Sarotherodon melanotheron) on their sound production features and social interactions. After 9 months in common garden rearing, from embryonic stage to first maturity, sound production and associated behaviours were recorded on specimens of the two species in intraspecific and interspecific pairings. The authors found that fish were able to produce the same kind of sounds as those recorded in similar context for their parents. Drum sounds were associated to chasing, lateral attack and courtship in O. niloticus and only to fleeing or avoidance in S. melanotheron. Specific grunts were produced in chasing, after biting and in nest building by O. niloticus, and specific rolling sounds were associated to courtship in S. melanotheron. Sound production and behaviours were not correlated to sex steroid levels, but the number of sounds recorded in aggressive context was correlated to dominance in O. niloticus. The authors conclude that one generation of common garden rearing does not modify sound features, which remain specific and innate in the two cichlids. Despite the familiarity, O. niloticus remained dominant on S. melanotheron, but the aggressiveness between the two species decreased. [ABSTRACT FROM AUTHOR]

Copyright of Compendium of Veterinary Sciences / Compendio de Ciencias Veterinarias is the property of Facultad de Ciencias Veterinarias de la Universidad Nacional de Asuncion and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Fish species assemblage and selected environmental variables were monitored in Lake Volta from September 2014 to August 2016 to determine seasonal variability in species composition, catch and environmental variables that determine the structure of the fish community. A total of 1,557 individual fish belonging to 41 species, 25 genera and 13 families were recorded. The important fish species with respect to frequency of occurrence, abundance and weight, respectively, were as follows: Chrysichthys (100%; 43.03%; 17.93%), tilapias (100%; 28.97%; 17.86%), Alestes (100%; 14.13%; 32.10%) and Bagrus (91.67%; 5.65%; 12.80%) in that order. The composition of fish species and their temporal variation in experimental catches were similar to that of commercial catches. There were no significant differences (p > 0.05) in species abundance, weight and diversity indices between the dry and wet seasons. The modal class of length frequency distribution of the dominant species in the catch, Chrysichthys, reduced from 125 mm in 2006 to 95 mm in the current study indicating overfishing. Environmental variables considered showed little variation and within optimal ranges for fish survival and did not differ significantly between seasons. Canonical Correspondence Analysis showed that environmental variables explained 43.30% of the variation in species abundance with Lake water level, nitrite‐nitrogen and total dissolved solids being the main environmental factors influencing the structure of the fish community. [ABSTRACT FROM AUTHOR]

Copyright of Parasite (1252607X) is the property of EDP Sciences and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

We have investigated gross pathology, physiological (steroid precursors) and toxicological responses (oxidative stress and phase II biotransformation) in relation to tissue contaminant burden in Tilapia species along the entire length (320 km) of Ogun River, Nigeria. The Ogun River is the longest and largest river in Southwestern Nigeria located along heavily industrialized cities and receives complex mixtures of effluents. A total of 1074 tilapias were collected from three sampling points (Abeokuta, Isheri and Ikorodu) and from an upstream control point (Igboho) and evaluated for gross pathological changes, hepatic transcript levels for oxidative stress and phase II biotransformation responses. Trace metal concentrations and POPs in muscle samples were analyzed using ICP-MS and GC-MS respectively. Evaluation of gross pathological changes showed a 50-, 33-, 17 and 0% prevalence of hepatic tumors at the Ikorodu, Abeokuta, Isheri and Igboho sites, respectively. Plasma concentrations of cholesterol and pregnenolone showed apparent significant decreases at downstream sites of the control point in both male and female fish (except for pregnenolone levels of male fish at Ikorodu). Inversely, gst, ugt -1, ZuCu-sod and sod significantly increased in fish collected from downstream sites, compared with the control site and these increases paralleled the significant increase in trace metal and POPs concentrations at these sites. PCA revealed a site related association between measured toxicological responses and contaminant burden, indicating a potential cause-and-effect relationship. Thus, the possible adaptation of Ogun River Tilapia species to contaminants may have significant consequences on cellular, physiological and biochemical processes regulating metabolism, growth, development and reproduction, and also have serious human health consequences, since the Ogun River is used for fisheries and domestic water supply for surrounding neighborhoods. [ABSTRACT FROM AUTHOR]

Copyright of Revista Cientifica de la Facultade de Veterinaria is the property of Universidad del Zulia, Facultad de Ciencias Veterinarias and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Veterinaria Brasilica is the property of Acta Veterinaria Brasilica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

O trabalho foi realizado com objetivo de determinar os coeficientes de digestibilidade aparente (CD) da matéria seca (MS), proteína bruta (PB), energia bruta (EB) e a disponibilidade dos aminoácidos (AA), fósforo (P) e cálcio (Ca) da farinha de resíduos da indústria de filetagem de tilápias (FT) para a tilápia do Nilo. Foram utilizadas 60 tilápias com peso e comprimento médio de 80,69±15,97g e 15,97±1,87cm, respectivamente. Os animais foram submetidos à metodologia de coleta de fezes por sedimentação em tanques afunilados. A MS, PB e EB da FT apresentaram CD de 83,55, 88,13 e 84,74%, respectivamente. Apresentando valores de proteína e energia digestíveis de 44,39% e 3799,02Kcal de ED kg-1. A FT apresenta CDa médio dos AA de 91,60% com CDas variando de 67,90% para a Fen até 100% para a Arg e a Cis. O CD do P foi de 70,44% apresentando 1,94% de P disponível, o CDa do Ca da FT é de 51,10% apresentando 4,02% de Ca disponível. A FT é um alimento protéico com bons índices de disponibilidade aparente de seus nutrientes e pode ser utilizado na alimentação de tilápias com a aplicação destes índices visando formular rações de custo mínimo que atendam às exigências da espécie.Coefficients of apparent digestibility (CD) of dry matter (DM), crude protein (CP), crude energy (CE) and the availability of amino-acids (AA), phosphorus (P) and calcium (Ca) of meals from tilapia filleting industrial waste (FT) for the Nile tilapia were determined. Sixty tilapias, mean weight and length 80.69±15.97g and 15.97±1.87cm respectively, underwent feces collection by sedimentation in cone-bottom tanks. DM, CP and BE of FT had a CD of 83.55; 88.13 and 84.74% respectively, with digestible protein and energy rates equivalent to 44.39% and 3799.02 Kcal of ED kg-1. FT had average CD of AA of 91.60%, with CD varying from 67.90% for Fen up to 100% for Arg and Cis. Whereas CD of P was 70.44% with 1.94% of available P, CD of Ca of FT amounts to 51.10% with 4.02% of Ca available. FT is a protein feed with a good index of apparent availability of its nutrients and may be used in feed of tilapia. Above indexes will produce low cost feeds that also meet the requirements of the fish.

A produção de tilápias vem se destacando como uma atividade capaz de propiciar oportunidades aos produtores familiares de regiões semi-áridas, visto a produção de peixes em açudes, poços e lagoas, sendo esta fundamental à sobrevivência das comunidades e produtores familiares da região. O objetivo geral deste trabalho é avaliar o desempenho das organizações familiares produtoras de tilápias, representantes da realidade produtiva na região semi-árida no Rio Grande do Norte. A metodologia utilizada foi o estudo de caso, com amostragem intencional de organizações de produção familiar, representantes da realidade produtiva de tilápias na região semi-árida potiguar. Para análise do desempenho foi utilizado o ferramental de "Escala de Likert", identificando indicadores de competitividade para os diferentes segmentos da cadeia produtiva, podendo influenciar o desempenho global da cadeia produtiva. Em complemento, utilizou-se a matriz de importância e desempenho de Slack, visando ordenar os graus de importância e de influência destes no desempenho geral. Por fim, este trabalho mostra a possibilidade de se utilizar as ferramentas de análises, normalmente utilizadas para grandes sistemas agroindustriais, para a produção familiar, visando destacar suas condições e dificuldades. Ainda, indica itens relevantes para pesquisas específicas a cadeia produtiva de tilápias, no âmbito de produção familiar.The Tilápia’s production has detached like a activity wich confer chances for famlily’s producers of semi-árida region, with a production of fishes in dams, wells and lakes, basic for surviver of communities and producers, of semi-árida region. The general objective this paper was evaluate the performance of family’s organization producers of tilápias, representantive of the productive reality in the semi-árida region of Rio Grande do Norte. The methodology was the case study with intentional sampling of familie’s organizations, representative of reality tilápia’s of family’s production in the region potiguar’s semi-árido. For analise of performance it used the tool of "Escala de Likert", identifying competitive’s pointers to differents segments of suply chain, and influencing the global preformance of suply chain. It used the matrix of importance and performance os Slack, in complement, to command the degrees of importance and these influence in the general performance. Finally, this research show the possibility to use the analysis tools, normally use for biggers agroindustrials sistems, for family production, detaching its conditions and dificulties. Also, it indicates itens excellent for specifies research for tilápia’s suply chain, in the scope of family’s production.

A major development in fishery science has been the Fulton's condition factor (CF) as a reliable physiological index of fish growth and health status (Fulton 1902). As a general rule, CF-value greater than 1 (> 1) should be regarded as an indicator for good growth and health. Therefore, exposure of fish to contaminants in the environment will be expected to produce a reduction in scope for growth, since energy for growth will be allocated to overcome stressful conditions. In the present study, we hypothesized that tilapia species from Ogun River (Nigeria) are experiencing severe contaminant-induced obesogen effects leading to high CF (≥ 2) in fish with pathological alterations. The environmental obesogen hypothesis has related the interaction between environmental pollutants and PPAR isoform activation In this respect, peroxisome proliferator-activated receptors (PPARs) and biotransformation responses in relation to contaminant burden were investigated in a total of 1074 specimens of Tilapias species ( Tilapia guineensis , Sarotherodon galileaus and Oreochromis niloticus ) collected from three areas with different degrees of anthropogenic contamination and from a putative control site along the Ogun River. Liver mRNA expression of cytochrome cyp1 isoforms (cyp1a, 1b and 1c) and PPAR isoforms ( ppar -α, β and γ) were analyzed using validated real-time PCR. Fish were also analyzed for CF and muscle contaminant burden (aliphatic and polycyclic aromatic hydrocarbons, organochlorine pesticides, and polychlorinated biphenyls). A significant increase in mRNA expression of cyp 1- and ppar isoforms was observed in fish from polluted areas, and these results paralleled data on PCBs and PAHs tissue concentrations. Further, cyp 1 isoforms showed clear sex-related differences, with higher mRNA expression in male fish than in females. Principal component analysis revealed a relationship between cyp 1 isoforms, ppar -α, β, PCBs and PAHs and these interactions may suggest a crosstalk between AhR- and PPARs mediated pathways on metabolic and energetic processes. The PCA biplot also highlighted a positive relationship between ppar -γ, body weight, total length and PAHs. The CF for fish from all the sites was ≥ 2 indicating that this parameter may not be a reliable index for evaluating fish growth and health condition, especially in wild fish population exposed to complex cocktails of environmental pollutants. [ABSTRACT FROM AUTHOR]

Foi avaliada a composição química de vísceras de tilápias (Oreochromis niloticus) criadas em cativeiro Os teores de umidade, cinza, proteína bruta e lipídios totais foram de 64,4%; 1,3%; 6,3% e 18,0%, respectivamente, caracterizando alta concentração de lipídios totais em relação a outros resíduos de peixes. Foram identificados 49 ácidos graxos, sendo majoritários os ácidos: oléico, (32,8%), seguido do palmítico, (19,9%) e linoléico, (18,2%). As razões entre n-6/n-3 e ácidos poliinsaturados/saturados foram de 5,5 e 0,9, respectivamente. As quantificações dos ácidos graxos alfa-linolênico, eicosapentaenóico e docosahexaenóico, em mg/g de lipídios totais, foram de 10,4, 1,4 e 9,3, respectivamente. O elevado teor de lipídios totais das vísceras contribuiu significativamente para as quantidades de ácidos graxos n-3. Todos os parâmetros analisados foram satisfatórios sob o ponto de vista nutricional e neste sentido as vísceras de tilápias poderão ser utilizadaa para alimentar peixes ou outros animais.

Foi avaliada a composição química de vísceras de tilápias (Oreochromis niloticus) criadas em cativeiro Os teores de umidade, cinza, proteína bruta e lipídios totais foram de 64,4%; 1,3%; 6,3% e 18,0%, respectivamente, caracterizando alta concentração de lipídiostotais em relação a outros resíduos de peixes. Foram identificados 49 ácidos graxos, sendo majoritários os ácidos: oléico, (32,8%), seguido do palmítico, (19,9%) e linoléico, (18,2%). As razões entre n-6/n-3 e ácidos poliinsaturados/saturados foram de 5,5 e 0,9, respectivamente. As quantificações dos ácidos graxos alfa-linolênico, eicosapentaenóico e docosahexaenóico, em mg/g de lipídios totais, foram de 10,4, 1,4 e 9,3, respectivamente. O elevado teor de lipídios totais das vísceras contribuiu significativamente para as quantidadesde ácidos graxos n-3. Todos os parâmetros analisados foram satisfatórios sob o ponto de vista nutricional e neste sentido as vísceras de tilápias poderão ser utilizadaa para alimentar peixes ou outros animais.The chemical composition was evaluated in visceras of tilapias raised in captivity. The moisture, ash, crude protein and total lipids contents were 64.4%; 1.3%; 6.3% and 18.0%, respectively, characterizing high total lipids concentration in relation other residues of fish. Forty nine fatty acids were detected, the major fatty acids were oleic (32.8%), palmitic (19.9%) and linoleic-1 (18.2%) and oleic (9.4%). The ratio n-6/n-3 and polyunsaturated/saturated fatty acids, showed the values 5.5 and 0.9, respectively. The quantifications of alfa-linolenic, eicosapentaenoic and docosahexaenoic acids (in mg/g of total lipids), were 10.4, 1.4 and 0.3, respectively. The higher contents of total lipids in visceras contributed significantly for amounts of n-3 fatty acids. All the parameters analyzed were shown nutritional value satisfactory in this sense visceras of tilapias can be used in the feed of fish and other animal.

Se hace un llamado de alerta ante la posible introducción de la tilapia roja (Oreochromis sp.) a Chile, con fines de cultivo. Se analizan los llamados cultivos monosexuales (solo machos), señalados como la solución para impedir la reproducción no deseada, que evitaría riesgos para la biodiversidad y se demuestra la falsedad de este argumento. Énfasis especial se da a los cultivos de tilapia en áreas marinas. Los peligros para la biodiversidad, son resaltadosA call of attention is made over the possible introduction of red tilapia (Oreochromis sp.) for aquaculture in Chile. The so-called monosex (all male) culture, considered by some as the solution for unwanted reproduction and for avoiding risks for biodiversity, are analyzed, and the falsehood of this argument is demonstrated. Special emphasis is given to the tilapia culture in marine areas. Threats to biodiversity are stressed

Edwardsiella tarda causes fish disease and great economic loss. However, metabolic strategy against the pathogen remains unexplored. In the present study, GC–MS based metabolomics was used to investigate the metabolic profile from tilapias infected by sublethal dose of E. tarda . The metabolic differences between the dying group and survival group allow the identification of key pathways and crucial metabolites during infections. More importantly, those metabolites may modulate the survival-related metabolome to enhance the anti-infective ability. Our data showed that tilapias generated two different strategies, survival-metabolome and death-metabolome, to encounter EIB202 infection, leading to differential outputs of the survival and dying. Glucose was the most crucial biomarker, which was upregulated and downregulated in the survival and dying groups, respectively. Exogenous glucose by injection or oral administration enhanced hosts' ability against EIB202 infection and increased the chances of survival. These findings highlight that host mounts the metabolic strategy to cope with bacterial infection, from which crucial biomarkers may be identified to enhance the metabolic strategy. [ABSTRACT FROM AUTHOR]

Cage culture of tilapia ( Oreochromis niloticus ) in large reservoirs is an emergent aquaculture practice in Brazil. Due to the availability of large amounts of suitable quality waters in hydroelectric dams, there is a large but still undetermined potential for cage aquaculture in the upper Paraná River basin. Sustainable aquaculture production should consider assessment of ecological carrying capacity for rational use of natural resources such as water bodies. The present survey estimates the ecological carrying capacity for tilapia cage culture in several sites on a large reservoir of “Ilha Solteira” upper Paraná River basin, Southeastern Brazil. Ecological carrying capacity was estimated based on the Dillon and Rigler (1975) mass balance model, considering limnological and farming field data to evaluate area-specific Phosphorus loads that can be assimilated in these environments. Using average farming data of feed composition, tilapia ( O. niloticus ) whole body composition and Feed Conversion Rate (FCR), the estimated emission of Phosphorus per ton of fish produced was 14.8 kg P ton −1 . Modeling provided evidence for the importance of feed Phosphorus content and availability for determination of total allowable production, as well as the relevance of proper inputs of limnological field data. When field data was collected, only two sites (Ponte Pensa and Dourados) had aquaculture activities; as aquaculture is expanding, limnological information provided in the present study is a registry of conditions found before the massive aquaculture development. Production estimated to the reservoir as a whole (156,000 ton) is more than fivefold the pooled production (30,000 ton) of the fifteen selected sites; if production estimated to the reservoir as a whole cluster around a few best sites, than effects on water quality is expected to be even more drastic. The limit of 1% occupancy by aquaculture posed by Brazilian government is not an effective safeguard against excessive eutrophication, and detailed limnological studies are demanded for each inlet assigned for cage aquaculture. The impact of cage fish farming on the aquatic environment by the release of nutrients that affect water quality can not only bring about conflict with multiple users, but also primarily exert a negative feedback effect in the cage operations themselves. [ABSTRACT FROM AUTHOR]

By using freshwater fish stocking information from the Mexican government, this work described the current situation of the national stocking and its associated fishery policy. There is a lack of effective freshwater stocking programmes as a result of limited fisheries management, unharmonized fisheries regulations and institutional performance. The fry production has decreased from 140 to 20 million in the past 11 years. [ABSTRACT FROM AUTHOR]

Plesiomonas shigelloides es un bacilo Gram negativo, anaerobio facultativo, móvil, que pertenece a la familia Enterobactereaceae. No forma parte de la flora normal del humano, mientras que los peces dulceacuícolas como las tilapias se tienen como su reservorio primario. Considerando: a) La implicación cada vez más frecuente de este microorganismo como agente causal de enfermedades intra y extra intestinales, b) El incremento de la comercialización de tilapias silvestres y de cultivo a nivel nacional y c) La necesidad de métodos de detección e identificación rápidos y efectivos de patógenos, se aplicó el método biomolecular de la Reacción en Cadena de la Polimerasa (PCR). Se procesaron mediante la PCR, cepas de P. shigelloides y homogeneizados de pools de bazo, riñón y cerebro, y de intestino de tilapias, utilizándose oligonucleótidos iniciadores específicos para el gen 23S ARNr de P. shigelloides. Se obtuvo el reconocimiento del 75% de las 20 cepas identificadas por pruebas fenotípicas convencionales, detectándose además en 27% de los homogeneizados frescos y en 18% de los congelados. Estos resultados confirman la especificidad del método para la identificación de diversas bacterias potencialmente patógenas, su utilidad en el mejoramiento del sistema de control de calidad de granjas dulceacuícolas y en el estudio de casos clínicos, aumentando la efectividad del sistema de salud relacionado con estas áreas.

The fisheries sector in the course of the last three decades have been transformed from a developed country to a developing country dominance. Aquaculture, the farming of waters, though a millennia old tradition during this period has become a significant contributor to food fish production, currently accounting for nearly 50 % of global food fish consumption; in effect transforming our dependence from a hunted to a farmed supply as for all our staple food types. Aquaculture and indeed the fisheries sector as a whole is predominated in the developing countries, and accordingly the development strategies adopted by the sector are influenced by this. Aquaculture also being a newly emerged food production sector has being subjected to an increased level of public scrutiny, and one of the most contentious aspects has been its impacts on biodiversity. In this synthesis an attempt is made to assess the impacts of aquaculture on biodiversity. Instances of major impacts on biodiversity conservation arising from aquaculture, such as land use, effluent discharge, effects on wild populations, alien species among others are highlighted and critically examined. The influence of paradigm changes in development strategies and modern day market forces have begun to impact on aquaculture developments. Consequently, improvements in practices and adoption of more environmentally friendly approaches that have a decreasing negative influence on biodiversity conservation are highlighted. An attempt is also made to demonstrate direct and or indirect benefits of aquaculture, such as through being a substitute to meet human needs for food, particularly over-exploited and vulnerable fish stocks, and for other purposes (e.g. medicinal ingredients), on biodiversity conservation, often a neglected entity. [ABSTRACT FROM AUTHOR]

Copyright of Revista Luna Azul is the property of Universidad de Caldas and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Revista de Economia e Sociologia Rural is the property of Sociedade Brasileira de Economia e Sociologia Rural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Asia dominates global aquaculture production accounting for over 80% of the total and the mainstay in Asian aquaculture is finfish. Over the years, Asia has experienced a number of inter-continental and intra-continental transfers/introductions/translocation of finfish species, between nations and watersheds, beyond their natural range of distribution, primarily for aquaculture development. In this article all such species are referred to as alien species. An attempt is made to evaluate the importance of the production of alien species in selected Asian nations, using statistics of the Food and Agriculture Organization. Also, negative effects, if any, based on literature surveys, of alien species in relation to displacement of indigenous species, and on biodiversity and/or genetic diversity together with associated pathogen transfers are evaluated. The major alien species, based on their significance to Asian inland aquaculture considered, are the tilapias, catfish, Chinese and Indian major carps and common carp. It is estimated that currently alien species account for nearly 12% of the cultured finfish production (2.6 million tonnes) in Asia, valued at US$ 2.59 billion, and the contribution exceeds 40% when Asian countries excluding China are taken into consideration. Inland finfish aquaculture in some Asian nations, such as Indonesia and the Philippines, is predominated by alien species, and in some others, e.g. Bangladesh and India, the contribution from alien species has been increasing steadily. It is suggested that overall alien finfish species have done little ecological harm to native flora and fauna. However, in the wake of increasing anthropogenic development taking place in watersheds the resulting environments are often made unconducive to indigenous species but not to some alien species, thereby potentially and indirectly making the latter invasive. [ABSTRACT FROM AUTHOR]

Abstract: Lipids extracted from three tilapia species (Oreochromis niloticus, O. macrochir and Tilapia rendalli) of mean weight 100–250 g collected in Itasy lake of Madagascar highlands during three seasons, were analyzed for their fatty acid compositions. The muscle fishes contained less than 1.4% lipid by weight. Gas chromatography (GC) and gas chromatography–mass spectrometry (GC–MS), allowed identification of more than 40 fatty acids and 30 of them were quantified in muscle tissue lipids of fishes. Among them, those occurring in the highest proportions were palmitic, stearic, oleic, palmitoleic and linoleic acids. The main polyunsaturated fatty acids were arachidonic acid, eicosa-5,8,11,14,17-pentaenoic acid (EPA) and docosa-4,7,10,13,16,19-hexaenoic acid (DHA). The relative amount of these acids changed significantly between species and season of collect, in particular DHA which decreased from 11.4% to 6.0% for O. macrochir during the spring to autumn period. For O. niloticus and T. rendalli, DHA decreased from 9.8% to 4.9% and to 10.1% to 4.4%, respectively during the same period. Therefore the ∑n−3/∑n−6 ratios vary, for each species according to season of collect, being lower in autumn (0.5–0.6) and raising up to 0.7–1.6 in winter. Multivariate statistical analyses, starting from the fatty acid composition, lipid percentage and biometric ratio (weight/size) data of 113 samples, reveals significative differences between species and season of collect. Furthermore differences in fatty acid profiles are higher within season than species. The results show that wild tilapias from tropical lakes of the Madagascar highlands possess beneficial properties and therefore contribute significantly of the n−3 fatty acids intake of the local population diet. [Copyright &y& Elsevier]

Within the tilapiines, a major African cichlid lineage, quite limited genetic informations are available on phylogenetic interrelationships and phylogeographical patterns at both macro- and micro-evolutionary scales. The present study examines the genetic diversity of the black-chinned tilapia complex from coastal areas in West Africa (Senegal to Congo-Brazzaville) based on mtDNA control region sequences. Phylogenetic inferences provide support for the monophyly of both taxa involved. It is suggested that Sarotherodon melanotheron and Sarotherodon nigripinnis have diverged probably since the early Pleistocene. The occurrence of the main intraspecific lineages could be dated back to about 500,000–900,000 years. Our data suggest that West African Pleistocene refuge zones may have strongly influenced the degree and level of genetic differentiation among populations and thus the observed phylogeographic patterns. The spatial distribution of mtDNA lineages and the centres of intrapopulational genetic diversity clearly correspond to proposed lowland refuge zones and core areas of Central Africa. Moreover, this study genetically supports the existence of Sarotherodon melanotheron leonensis for the first time and further confirms the validity of the most recently introduced subspecies, e.g., Sarotherodon nigripinnis dolloi. [Copyright &y& Elsevier]

Simple Summary: This study presents in silico models of neurokinin B receptor tiTac3Ra (tilapia Tachykinin 3 receptor a) and its potential binding sites, as well as docking native tilapia Neurokinin F (tiNKF) and tilapia Neurokinin B (tiNKB) to theses orthosteric binding sites. For a better understanding of the binding confirmation and interaction of the structures, we compared the conformation between peptide docking and induced fit docking results. We have tried to analyze the affinity of binding and binding site interactions parallel to in-vitro results of receptor activity. NKB antagonists inhibit male tilapia gonadal development and gonadotropin release. We further verified the in-vivo effect of the antagonists on gonadal development in males. Studying the receptor activity of variants with alanine mutations at Phe2516.44 and Met2897.43 respectively, we found that, while both variants completely underperformed, there was no direct interaction with the ligand in the binding process indicating their role in post binding receptor activation rather than the binding process itself. NKB (Neurokinin B) is already known to play a crucial role in fish reproduction, but little is known about the structure and function of NKB receptors. Based on an in silico model of the tilapia NKB receptor Tachykinin 3 receptor a (tiTac3Ra) found in the current study, we determined the key residues involved in binding to tilapia NKB and its functional homologue NKF (Neurokinin F). Despite studies in humans suggesting the crucial role of F2516.44 and M2897.43 in NKB binding, no direct peptide interaction was observed in tilapia homologs. In-silico, Ala mutations on residues F2516.44 and M2897.43 did not influence binding affinity, but significantly affected the stability of tiTac3Ra. Moreover, in vitro studies indicated them to be critical to tiNKB/tiNKF-induced receptor activity. The binding of NKB antagonists to tiTac3Ra both in-vitro and in vivo inhibits FSH (follicle stimulating hormone) and LH (luteinizing hormone) release and sperm production in mature tilapia males. Non-peptide NKB antagonist SB - 222200 had a strong inhibitory effect on the Tac3Ra activation. SB - 222200 also decreased LH plasma levels; two hours post intraperitoneal injection, changed sperm volume and the ratios of the different stages along the spermatogenesis in tilapia testes. [ABSTRACT FROM AUTHOR]

Haemoglobins of five tilapiine species of the genera Oreochromis and Sarotherodon were investigated. By gel filtration chromatography a molecular weight of 67–69 kDa was determined for the tetrameric molecules which remained stable between pH 5.0 and pH 9.1. When subjected to sodium dodecyl sulphate-Urea-polyacrylamide gel electrophoresis (PAGE), haemoglobins of all species each were split into monomers of three different molecular weights ranging between 16.3 kDA and 17.6 kDa. Subsequently, isoelectric focusing separated haemolysates into about 23 differently charged tetrameric haemoglobins that were arranged in species-specific patterns. This diversity was shown to result from the occurrence of different types of globin chains. By acidic urea PAGE a total of seven major α-globins and five major β-globins were detected and species-characteristic chain variants were identified. To determine the globin chain composition of particular haemoglobin tetramers, 26 bands were isolated by isoelectric focusing and analysed by acidic urea PAGE. Tetramers consisted of doublets of identical α- and identical β-chains (α2β2, symmetric tetramers), or combinations of three (α2ββ*; αα*β2) or four (αα*ββ*) distinct chains (asymmetric tetramers). Finally, globin chains of Oreochromis niloticus were subjected to partial N-terminal amino acid sequencing. Differences in the composition of the three major β-chains could be shown, whereas the α-chains were N-terminally blocked. [ABSTRACT FROM AUTHOR]

Abstract: We developed a high throughput DNA extraction protocol from tilapia fin tissue that enables the use of 96-well plates using a fluid micro-dispenser robot, thus effectively decreasing the time, cost and handling error of the DNA preparation stage. The method is based on the DNA salting out procedure and all fluid transfers are designed for use with a micro dispenser robot. The criterion of success was defined as extraction of at least 2 μg of DNA, which enables at least 100 PCR reactions. A total of 3163 samples met this criterion (98%). The cost of the proposed in-house protocol is approximately ten-fold lower than the commercial alternatives. The suggested high-throughput extraction protocol may be adjusted by slight modifications to handle other tissues. [Copyright &y& Elsevier]