RESUMO
Strain T-12T, an orange, Gram-stain-negative, non-motile, rod-shaped strain, was isolated in November 2013 from water samples collected from an Atlantic salmon (Salmo salar) fry culturing system at a fish farm in Chile. Phylogenetic analysis based on 16S rRNA sequences (1394 bp) revealed that strain T-12T belonged to the genus Flavobacterium, showing close relationships to Flavobacterium bernardetii F-372T (99.48â%) and Flavobacterium terrigena DS-20T (98.50â%). The genome size of strain T-12T was 3.28 Mb, with a G+C content of 31.1âmol%. Genome comparisons aligned strain T-12T with Flavobacterium bernardetii F-372T (GCA_011305415) and Flavobacterium terrigena DSM 17934T (GCA_900108955). The highest digital DNA-DNA hybridization (dDDH) values were 42.6â% with F. bernardetii F-372T (GCA_011305415) and 33.9â% with F. terrigena DSM 17934T (GCA_900108955). Pairwise average nucleotide identity (ANI) calculations were below the species cutoff, with the best results with F. bernardetii F-372T being: ANIb, 90.33â%; ANIm, 91.85â%; and TETRA, 0.997â%. These dDDH and ANI results confirm that strain T-12T represents a new species. The major fatty acids were iso-C15â:â0 and C15â:â1ω6Ñ. Detected polar lipids included phospholipids (n=2), aminophospholipid (n=1), aminolipid (n=1) and unidentified lipids (n=2). The predominant respiratory quinone was menaquinone MK7 (80â%) followed by MK-6 (20â%). Phenotypic, chemotaxonomic, and genomic data support the classification of strain T-12T (=CECT 30410T=RGM 3222T) as representing a novel species of Flavobacterium, for which the name Flavobacterium facile sp. nov. is proposed.
Assuntos
Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano , Ácidos Graxos , Flavobacterium , Hibridização de Ácido Nucleico , Filogenia , RNA Ribossômico 16S , Salmo salar , Análise de Sequência de DNA , Vitamina K 2 , Animais , Flavobacterium/genética , Flavobacterium/isolamento & purificação , Flavobacterium/classificação , RNA Ribossômico 16S/genética , Ácidos Graxos/análise , Salmo salar/microbiologia , DNA Bacteriano/genética , Chile , Vitamina K 2/análogos & derivados , Vitamina K 2/análise , Microbiologia da Água , Fosfolipídeos/análiseRESUMO
The starch extracted from avocado (Persea americana L. cv. Hass) seeds was characterized and used in the preparation of an edible coating to reduce the oil uptake and acrylamide content in French fries. Starch characterization was carried out using Differential Scanning Calorimetry, Fourier transform infrared spectrophotometry, gelatinization, and scanning electron microscopy. Uncoated (UFF) and coated (CFF) French fries were compared and evaluated for moisture, water activity (Aw), fat, color, firmness, acrylamide content, and sensorial analysis. The extracted starch presented a high crystalline structure and good stability to mechanical work and heat treatments. The CFF French fries showed significantly higher Aw, color parameter a*, but lower luminosity and acrylamide content than UFF samples. Similarly, the CFF samples tended to decrease the fat content, although without statistical differences. Avocado seed starch can be an economical and technically feasible alternative to the food industry as an effective coating to reduce acrylamide content in French fries.
RESUMO
This work evaluated the performance of potato clones for some agronomic and processing traits, in subtropical and high-altitude tropical regions, under conventional and organic production systems. Experiments were conducted in spring of 2017 and 2018 in Canoinhas-SC (subtropical), under the conventional system, and in winter of 2018 and 2019 in Brasília-DF (tropical), Brazil, under conventional and organic systems. Eleven advanced clones and cultivars Agata (fresh), Atlantic (chipping) and Asterix (French fry) were evaluated. RCBD with tree replications was used, and tuber yield and processing traits, plant vigor and cycle were evaluated. It was not possible to select high yielding and good processing quality clones with short cycle and less vigorous plants. It because higher yield and larger tuber size were attained by longer cycle genotypes, which had higher specific gravity, but darker frying color. The most outstanding clones differed with region and production system. For chipping, in the subtropical region, no clone had adequate quality, but in tropical F177-11-20 presented similar processing traits and higher or similar yield to 'Atlantic' in both systems, and also ORG7785 in organic. Comparing with Asterix, for French fry, in the subtropical region, superior or similar to the standard this cultiva rwere F129-10-06 and F163-11-01; while in the tropical region and conventional system, were the clones ORG7785, F129-10-06, F163-11-01, F177-11-20, ORG6464, ORG 6377, F05-11-03, Odone 80-02 and F174-11-01; and in organic system, the best clones were F54-11-03, ORG7785, F129-10-06, F163-11-01, F177-11-20 and ORG6464.(AU)
Neste trabalho foi avaliado o desempenho de clones de batata para caracteres agronômicos e de qualidade de processamento, em regiões subtropical e tropical de altitude, sob sistema convencional e orgânico de produção. Os experimentos foram conduzidos na primavera de 2017 e 2018 em Canoinhas-SC (subtropical), sobre sistema convencional, e nos invernos de 2018 e 2019 em Brasília-DF (tropical), Brasil, sob sistemas convencional e orgânico. Foram avaliados onze clones avançados e as cultivares Agata (mercado fresco), Atlantic (chips) e Asterix (palitos fritos). Foi utilizado delineamento em blocos casualisados com três repetições. Foram avaliados caracteres relacionados ao rendimento de tubérculos, qualidade de fritura, vigor de planta e ciclo vegetativo. Foi verificado que não foi possível selecionar clones com elevado rendimento de tubérculos e boa qualidade de fritura e com ciclo vegetativo precoce e com plantas menos vigorosas. Isso porque maior rendimento e maiores tamanhos de tubérculos foram associados com ciclo vegetativo mais longo, maior peso específico de tubérculos, porém cor mais escura de fritura. Os melhores clones diferiram com a região e sistemas de produção. Para chips, n aregião subtropical, nenhum clone apresentou bom desempenho, porém no ecossistema tropical, F177-11-20 apresentou similares qualidades industriais e maior ou superior produtividade em comparação com 'Atlantic' em ambos os sistemas de cultivo, também o clone ORG7785 no sistema orgânico. Para o mercado de fritura de palitos, portanto comparando com Asterix, na região subtropical, os clones F129-10-06 eF163-11-01foram superiores ou equivalentes a esta cultivar; enquanto que na região tropical em sistema convencional destacam-se os clonesORG7785, F129-10-06, F163-11-01, F177-11-20, ORG6464, ORG 6377, F05-11-03, Odone 80-02 eF174-11-01; e nos sistema orgânico os clonesF54-11-03, ORG7785, F129-10-06, F163-11-01, F177-11-20 eORG6464.(AU)
Assuntos
Solanum tuberosum/genética , Células Clonais , Melhoramento Vegetal , Brasil , Zona TropicalRESUMO
This work evaluated the performance of potato clones for some agronomic and processing traits, in subtropical and high-altitude tropical regions, under conventional and organic production systems. Experiments were conducted in spring of 2017 and 2018 in Canoinhas-SC (subtropical), under the conventional system, and in winter of 2018 and 2019 in Brasília-DF (tropical), Brazil, under conventional and organic systems. Eleven advanced clones and cultivars Agata (fresh), Atlantic (chipping) and Asterix (French fry) were evaluated. RCBD with tree replications was used, and tuber yield and processing traits, plant vigor and cycle were evaluated. It was not possible to select high yielding and good processing quality clones with short cycle and less vigorous plants. It because higher yield and larger tuber size were attained by longer cycle genotypes, which had higher specific gravity, but darker frying color. The most outstanding clones differed with region and production system. For chipping, in the subtropical region, no clone had adequate quality, but in tropical F177-11-20 presented similar processing traits and higher or similar yield to 'Atlantic' in both systems, and also ORG7785 in organic. Comparing with Asterix, for French fry, in the subtropical region, superior or similar to the standard this cultiva rwere F129-10-06 and F163-11-01; while in the tropical region and conventional system, were the clones ORG7785, F129-10-06, F163-11-01, F177-11-20, ORG6464, ORG 6377, F05-11-03, Odone 80-02 and F174-11-01; and in organic system, the best clones were F54-11-03, ORG7785, F129-10-06, F163-11-01, F177-11-20 and ORG6464.
Neste trabalho foi avaliado o desempenho de clones de batata para caracteres agronômicos e de qualidade de processamento, em regiões subtropical e tropical de altitude, sob sistema convencional e orgânico de produção. Os experimentos foram conduzidos na primavera de 2017 e 2018 em Canoinhas-SC (subtropical), sobre sistema convencional, e nos invernos de 2018 e 2019 em Brasília-DF (tropical), Brasil, sob sistemas convencional e orgânico. Foram avaliados onze clones avançados e as cultivares Agata (mercado fresco), Atlantic (chips) e Asterix (palitos fritos). Foi utilizado delineamento em blocos casualisados com três repetições. Foram avaliados caracteres relacionados ao rendimento de tubérculos, qualidade de fritura, vigor de planta e ciclo vegetativo. Foi verificado que não foi possível selecionar clones com elevado rendimento de tubérculos e boa qualidade de fritura e com ciclo vegetativo precoce e com plantas menos vigorosas. Isso porque maior rendimento e maiores tamanhos de tubérculos foram associados com ciclo vegetativo mais longo, maior peso específico de tubérculos, porém cor mais escura de fritura. Os melhores clones diferiram com a região e sistemas de produção. Para chips, n aregião subtropical, nenhum clone apresentou bom desempenho, porém no ecossistema tropical, F177-11-20 apresentou similares qualidades industriais e maior ou superior produtividade em comparação com 'Atlantic' em ambos os sistemas de cultivo, também o clone ORG7785 no sistema orgânico. Para o mercado de fritura de palitos, portanto comparando com Asterix, na região subtropical, os clones F129-10-06 eF163-11-01foram superiores ou equivalentes a esta cultivar; enquanto que na região tropical em sistema convencional destacam-se os clonesORG7785, F129-10-06, F163-11-01, F177-11-20, ORG6464, ORG 6377, F05-11-03, Odone 80-02 eF174-11-01; e nos sistema orgânico os clonesF54-11-03, ORG7785, F129-10-06, F163-11-01, F177-11-20 eORG6464.
Assuntos
Células Clonais , Melhoramento Vegetal , Solanum tuberosum/genética , Brasil , Zona TropicalRESUMO
Flavobacterium psychrophilum is the causative agent of bacterial cold-water disease and rainbow trout syndrome in freshwater salmonid fish worldwide, generating injuries and high mortality rates. Despite several studies on this bacterium, the infection mechanism remains unknown due to limitations in the employed animal models. In this work, we propose using zebrafish (Danio rerio) as a model for studying bacterial pathogenicity. To substantiate this proposal, zebrafish infection by F. psychrophilum strain JIP 02/86 was characterized. Zebrafish larvae were infected using the bath method, and morphological changes and innate immune system activation were monitored using transgenic fish. Salmonid-like infection phenotypes were observed in 4.74% of treated larvae, as manifested by fin, muscle and caudal peduncle damage. Symptomatic and dead larvae accounted for 1.35% of all challenged larvae. Interestingly, infected larvae with no infection phenotypes showed stronger innate immune system activation than specimens with phenotypes. A failure of function assay for myeloid factor pu.1 resulted in more infected larvae (up to 43.5%), suggesting that low infection rates by F. psychrophilum would be due to the protective actions of the innate immune system against this bacterium in zebrafish larvae. Our results support the use of zebrafish as an infection model for studying F. psychrophilum. Furthermore, the percentage of infected fish can be modulated by disturbing, to varying extents, the differentiation of myeloid cells. Using this evidence as a starting point, different aspects of the infection mechanism of F. psychrophilum could be studied in vivo.
Assuntos
Modelos Animais de Doenças , Doenças dos Peixes/microbiologia , Infecções por Flavobacteriaceae/veterinária , Flavobacterium/fisiologia , Peixe-Zebra , Animais , Infecções por Flavobacteriaceae/microbiologiaRESUMO
The aim of this study was to evaluate the effects of a probiotic, composed of Bacillus subtilis and Lactobacillus plantarum in Nile tilapia fry during the sex reversal phase under stress conditions caused by high stocking density. This experiment was conducted in the Fisheries Institute of São Paulo. The experiment design was completely randomized with four treatments: 1) probiotic added feed, 2) probiotic added to water, 3) probiotic added to feed and water and 4) control diet; with three replicates. The variables analyzed were: final weight, total length, specific growth rate, survival, intestinal microbiology and gene expression of TNF-α and HSP-70. The results of the zootechnical performance of growth and gene expression did not show significant differences between treatments in the parameters evaluated (P>0.05). In the intestinal tract of fry raised in water with added probiotic, log(10) CFU (7.72 ± 0.51) count of Bacillus spp. was higher than with other treatments which themselves did not differ significantly. It was concluded that the addition of a probiotic of Bacillus subtilis and Lactobacillus plantarum in the feed or water of Nile tilapia fry during the sex reversal phase did not affect the zootechnical performance of growth or expression the genes studied, but modified the intestinal microbiota.(AU)
Objetivou-se com este trabalho avaliar os efeitos da administração do probiótico composto de Bacillus subtilis e Lactobacillus plantarum em pós-larvas de tilápia-do-nilo, durante a fase de reversão sexual, em condições de estresse pela alta densidade de estocagem. O experimento foi realizado no Instituto de Pesca de São Paulo, e foi inteiramente casualizado com quatro tratamentos e cinco repetições. Sendo: 1) probiótico na ração; 2) probiótico na água; 3) probiótico na ração e água; 4) controle. As variáveis analisadas foram: peso final, comprimento total, taxa de crescimento específico, sobrevivência, microbiologia do trato intestinal e expressão dos genes TNF-α e HSP-70. Os resultados de desempenho zootécnico de crescimento e expressão gênica não apresentaram diferenças significativas entre os tratamentos nos parâmetros avaliados (P>0,05). No trato intestinal dos alevinos do tratamento com adição de probiótico na água, foi observado log(10) (7,72±0,51) UFC, superior à contagem de Bacillus spp. em comparação aos demais tratamentos, e estes não apresentaram diferenças estatísticas entre si. Conclui-se que a adição dos probióticos Bacillus subtilis e Lactobacillus plantarum, na dieta ou na água de criação das pós-larvas de tilápia-do-nilo, durante fase de reversão sexual não causaram melhora no desempenho zootécnico de crescimento e expressão gênica, mas modificou a composição bacteriana intestinal.(AU)
Assuntos
Animais , Probióticos/efeitos adversos , Ciclídeos/crescimento & desenvolvimento , Ciclídeos/microbiologia , Expressão Gênica , Bacillus subtilis , Lactobacillus plantarumRESUMO
The aim of this study was to evaluate the effects of a probiotic, composed of Bacillus subtilis and Lactobacillus plantarum in Nile tilapia fry during the sex reversal phase under stress conditions caused by high stocking density. This experiment was conducted in the Fisheries Institute of São Paulo. The experiment design was completely randomized with four treatments: 1) probiotic added feed, 2) probiotic added to water, 3) probiotic added to feed and water and 4) control diet; with three replicates. The variables analyzed were: final weight, total length, specific growth rate, survival, intestinal microbiology and gene expression of TNF-α and HSP-70. The results of the zootechnical performance of growth and gene expression did not show significant differences between treatments in the parameters evaluated (P>0.05). In the intestinal tract of fry raised in water with added probiotic, log(10) CFU (7.72 ± 0.51) count of Bacillus spp. was higher than with other treatments which themselves did not differ significantly. It was concluded that the addition of a probiotic of Bacillus subtilis and Lactobacillus plantarum in the feed or water of Nile tilapia fry during the sex reversal phase did not affect the zootechnical performance of growth or expression the genes studied, but modified the intestinal microbiota.
Objetivou-se com este trabalho avaliar os efeitos da administração do probiótico composto de Bacillus subtilis e Lactobacillus plantarum em pós-larvas de tilápia-do-nilo, durante a fase de reversão sexual, em condições de estresse pela alta densidade de estocagem. O experimento foi realizado no Instituto de Pesca de São Paulo, e foi inteiramente casualizado com quatro tratamentos e cinco repetições. Sendo: 1) probiótico na ração; 2) probiótico na água; 3) probiótico na ração e água; 4) controle. As variáveis analisadas foram: peso final, comprimento total, taxa de crescimento específico, sobrevivência, microbiologia do trato intestinal e expressão dos genes TNF-α e HSP-70. Os resultados de desempenho zootécnico de crescimento e expressão gênica não apresentaram diferenças significativas entre os tratamentos nos parâmetros avaliados (P>0,05). No trato intestinal dos alevinos do tratamento com adição de probiótico na água, foi observado log(10) (7,72±0,51) UFC, superior à contagem de Bacillus spp. em comparação aos demais tratamentos, e estes não apresentaram diferenças estatísticas entre si. Conclui-se que a adição dos probióticos Bacillus subtilis e Lactobacillus plantarum, na dieta ou na água de criação das pós-larvas de tilápia-do-nilo, durante fase de reversão sexual não causaram melhora no desempenho zootécnico de crescimento e expressão gênica, mas modificou a composição bacteriana intestinal.
Assuntos
Animais , Ciclídeos/crescimento & desenvolvimento , Ciclídeos/microbiologia , Expressão Gênica , Probióticos/efeitos adversos , Bacillus subtilis , Lactobacillus plantarumRESUMO
Resumen Este experimento tuvo como objetivo evaluar el desempeño productivo de alevinos de Piaractus brachypomus, al ser alimentados con dietas isoproteicas (34%) con siete niveles de energía bruta (EB) (3750, 3865, 3980, 4095, 4210, 4325, 4440 (Kcal/kg) con las siguientes relaciones de energía / proteína: 11,03; 11,37; 11,74; 12,04; 12,38; 12,72 y 13,06 Kcal EB/g PB. El diseño experimental fue completamente aleatorizado, con cuatro repeticiones. El experimento tuvo una duración de 60 días. Se usó un lote de 280 alevinos (peso medio inicial de 1,89 ± 0,14 g), en número de 10 peces por acuario. Se evalúo el efecto de las dietas en cuanto a peso final (PF), ganancia de peso (GP), consumo de alimento (CA), tasa de conversión alimenticia (TCA), tasa de crecimiento específica (TCE), consumo de proteína (CP), tasa de eficiencia proteica (TEP), consumo de energía (CE), tasa de eficiencia energética (TEE) y un análisis de carcasas del 10% de la población al día 60 del experimento. Finalmente, los datos fueron sometidos a un análisis de varianza (ANOVA). Se concluyó que el nivel mínimo de energía que atiende los requerimientos de esta especie es de 3980 Kcal/Kg, con una relación de EB: PB de 11,74 Kcal de EB/g de PB, siendo semejante estadísticamente (P>0,05) con los niveles superiores probados.
Abstract The purpose of this experiment was to evaluate the productive performance of Piaractus brachypomus fry, fed with isoproteic diets (34%) with seven levels of gross energy (EB) (3750, 3865, 3980, 4095, 4210, 4325,4440 Kcal / kg) with the next relations of gross energy / crude protein: 11,03; 11,37; 11,74; 12,04; 12,38; 12,72 and 13,06 Kcal EB / g PB. The experimental design was completely random, with four repetitions. The experiment lasted 60 days. A batch of 280 fry were used (initial average weight 1,89 ± 0,14 g) in number of 10 fishes per aquarium. The effect of the diets was evaluated in terms of final weight (PF), weight gain (GP), feed intake (CA), feed conversion rate (TCA), specific growth rate (TCE), protein consumption (CP), protein efficiency ratio (TEP), energy consumption (CE), energy efficiency rate (TEE) and an analysis carcasses of 10% of the population on day 60 of the experiment. Finally, the data were subjected in a variance analysis (ANOVA). It concluded that the minimum level of energy that meets the requirements of this specie is 3980 Kcal/ kg with a ratio of EB: PB 11,74 EB kcal / g of PB being statistically (P>0,05) similar to higher levels tested.
Resumo Esse experimento teve por objetivo avaliar o desempenho produtivo de alevinos de Piaractus brachypomus, sendo arraçoados com dietas isoproteicas (34%) com sete níveis de energia bruta (EB) (3750, 3865, 3980, 4095, 4210, 4325 e 4440 Kcal/kg) com as seguintes relações de energia bruta / proteína bruta: 11,03; 11,37; 11,74; 12,04; 12,38; 12,72 e 13,06 Kcal EB/g PB. O delineamento experimental foi inteiramente casualiado, com quatro repetições. O experimento teve duração de 60 dias. Empregou-se um lote de 280 alevinos (peso médio de 1,89 ±0,14 g) em número de dez peixes por aquário. Avaliou-se o efeito das dietas quanto ao peso final (PF), o ganho de peso (GP), o consumo de alimento (CA), a conversão alimentar (TCA), a taxa de crescimento específica (TCE), consumo de proteína (CP), taxa de eficiência proteica (TEP), consumo de energia (CE), taxa de eficiência energética (TEE) e uma análise das carcaças de 10% da população no dia 60 do experimento. Finalmente os dados foram submetidos a uma análise de variância (ANOVA). Concluiu-se que o nível de mínimo energia que atende as exigências da espécie é de 3980 Kcal/Kg, com uma relação de EB:PB de 11,74 Kcal de EB/g de PB, sendo estatisticamente semelhantes (P>0,05) com os níveis superiores testados.
RESUMO
Resumo Procurando desenvolver a perspectiva da bicha, empreende-se uma leitura crítica da obra de Peter Fry relativa à antropologia da homossexualidade como um meio para promover questionamentos à formação identitária do gay, que é base das políticas de diversidade sexual no Brasil. O paradigma cultural que Fry ajuda a estabelecer, contestando a abordagem naturalista da homossexualidade, possibilita um lugar para a bicha nas tramas do saber científico. Mas o impasse representacional em relação ao devir marca a obra de Fry. O resultado da reviravolta é a redução da bicha ao negativo, como o contrário da homossexualidade. Extemporânea e involuída, contudo, não seria a bicha produzida no seio da modernidade uma ruptura na ordem da evolução e do progresso, signo de um desvio histórico?
Resumen Buscando desarrollar la perspectiva de la bicha (el maricón), se emprende una lectura crítica de la obra de Peter Fry en la antropología de la homosexualidad como un medio para promover el cuestionamiento de la formación de la identidad de la comunidad gay, que es la base de las políticas de diversidad sexual en Brasil. El paradigma cultural que Fry ayuda a establecer, desafiando el enfoque naturalista de la homosexualidad, proporciona un lugar para la bicha en las parcelas del conocimiento científico. Pero un atolladero representacional en relación con el devenir marca el trabajo de Fry. El resultado de la voltereta es la reducción de la bicha a la negativa, como lo contrario de la homosexualidad. Extemporánea e involutiva, sin embargo, no sería la bicha producida dentro de la modernidad una ruptura en el orden de la evolución y del progreso, ¿signo de un desvío histórico?
Abstract In order to develop abichaperspective, a critical reading of Peter Fry's work on the anthropology of homosexuality functions as a means to promote questions about the identity construction of gays, which is the basis of sexual diversity policies in Brazil. The cultural paradigm that Fry helps to establish by challenging the naturalistic approach to homosexuality provides a place for the bicha in the scientific knowledge. However, a representational impasse in relation to its development marks Fry's work. It results on the reduction of thebichato a negative, as being the opposite of homosexuality. Being seen as extemporaneous and "un-evolved", however, wouldn't thebichaproduced within modernity be a rupture in the order of evolution and progress, and therefore a sign of historical deviation?
Assuntos
Identificação Social , Homossexualidade Masculina , Antropologia Cultural , BrasilRESUMO
Flavobacterium psychrophilum is the etiological agent of bacterial coldwater disease and the rainbow trout fry syndrome in salmonid aquaculture worldwide. However, there have been few studies into the capacity of F. psychrophilum to form biofilms and how these cellular accretions differ from planktonic cells or how they affect potential virulence. We evaluated the biofilm formation by three Chilean isolates of F. psychrophilum (LM-02-Fp, LM-06-Fp, and LM-13-Fp) and two non-Chilean strains (JIP02/86 and NCMB1947T), and compared biofilm and planktonic states to obtain insights into expression differences of virulence- and biofilm-related genes (VBRGs). Our findings are based on scanning confocal laser microscopy (SCLM) and LIVE/DEAD staining, enzymatic reactions, reverse transcription-quantitative PCR (RT-qPCR) of genes encoding putative virulence factors, and transcriptomes (RNA-Seq). The LM-02-Fp and NCMB1947T strains were the strongest and weakest biofilm producers, respectively. The strong-biofilm producer showed different physiological cell states distributed in different layers of mature biofilms, whereas the NCMB1947T biofilms consisted of cells arranged in a monolayer. WGA-binding exopolysaccharides would be the main components of their corresponding extracellular matrices. Transcriptomes of F. psychrophilum NCMB1947T and LM-02-Fp were clustered by state (biofilm vs. planktonic) rather than by strain, indicating important state-dependent differences in gene expression. Analysis of differentially expressed genes between states identified putative VBRGs involved in polysaccharide biosynthesis, lateral gene transfer, membrane transport (e.g., for drugs and Fe3+), sensory mechanisms, and adhesion, and indicated that about 60-100% of VBRGs involved in these processes was significantly upregulated in the biofilm state. Conversely, upregulated motility-related genes in the biofilm state were not identified, whereas a lower fraction of proteolysis-related genes (33%) was upregulated in biofilms. In summary, F. psychrophilum strains that produce different biofilm phenotypes show global transcriptional activity in the mature biofilm state that differs significantly from their planktonic counterparts. Also, different biofilm phenotypes share a genetic potential for virulence that is transcriptionally enhanced with respect to free-living cells. Our results suggest that the F. psychrophilum biofilm lifestyle acts as a reservoir for a given set of putative virulence factors, and recommend a deeper understanding of which could help prevent recurring infections in salmonid farms.
Assuntos
Biofilmes/crescimento & desenvolvimento , Flavobacterium/fisiologia , Flavobacterium/genética , Flavobacterium/crescimento & desenvolvimento , Perfilação da Expressão Gênica , Fenótipo , VirulênciaRESUMO
With the purpose of carrying out a diagnosis of the different pathologies that affect the salmon fry stage (Salmo salar) and analyze the regeneration phases of the organizational centers and subjacent tissue in case of an amputation, we realized a study that allowed identifying the temporary and spatial location of the Sonic Hedgehog (Shh) morphogen in hatched fry stage. Fifteen salmon fry (Salmo salar) were used. They were anesthetized with 5 % benzocaine (BZ-20®, Veterquímica), fixed in 10 % buffered formalin, and embedded in paraffin, Shh polyclonal antibody (Santa Cruz H-160, rabbit) was used diluted at 1/100. They were subsequently rinsed in PBS-1 % Triton and incubated with anti-rabbit conjugated polymer antibody and HRP for 10-15 min. The development was done with DAB (Vector) for 1-5 min. The negative control was incubated without primary antibody. As an internal positive control the notochord was considered. Serial sagittal sections were analyzed consigning tissues and organs marked positively and were described morphologically. The objective of recognizing the spatial and temporal location of Shh was achieved. The notochord, spinal cord neurons and ganglia, the basal layer of the skin and also the lepidotriquias escleroblastos were positively identified for Shh. Finally positivity was also observed in the intestine and renal tubules. The heterogeneity observed in the location of the Shh morphogen suggests its potential use as a marker of regulatory centers in Salmo salar, and a potential advantage in the diagnosis of malformations of salmon fry stage, in addition to a better understanding of tissue regeneration.
Con el fin de llevar a cabo un diagnóstico de las diferentes patologías que afectan a la etapa de alevín de salmón (Salmo salar) y analizar las fases de regeneración de los centros de organización y el tejido subyacente en caso de una amputación, se realizó un estudio que permitió identificar la ubicación temporal y espacial del morfógeno Sonic hedgehog (Shh) en la etapa de alevines eclosionados. Se utilizaron quince alevines de salmón (Salmo salar). Fueron anestesiados con benzocaína al 5% (BZ-20®, Veterquímica), se fijaron en formalina tamponada al 10%, e incluidos en paraplast. Se utilizó Shh anticuerpo policlonal (Santa Cruz H-160, conejo) dilución 1/100. Se enjuagaron posteriormente en PBS-1% Triton y se incubaron con anticuerpo conjugado con polímero anti-conejo y HRP durante 10-15 minutos. Se utilizó como sustrato DAB (Vector) durante 1-5 minutos. El control negativo se incubó sin anticuerpo primario. Como un control positivo interno se consideró la notocorda. Se analizaron secciones sagitales en serie consignando los tejidos y órganos marcados positivamente y se describieron morfológicamente. Se logró el objetivo de reconocer la localización espacial y temporal de Shh. La notocorda, las neuronas de la médula espinal y los ganglios, la capa basal de la piel y también los escleroblastos de las lepidotriquias fueron identificados positivamente para Shh. También se observó positivo el intestino y los túbulos renales. La heterogeneidad observada en la ubicación del morfógeno Shh sugiere su uso potencial como un marcador de los centros de regulación en Salmo salar, y una ventaja potencial en el diagnóstico de las malformaciones de la etapa de alevines de salmón, además de una mejor comprensión de la regeneración de tejidos.
Assuntos
Animais , Doenças dos Peixes/metabolismo , Doenças dos Peixes/patologia , Proteínas Hedgehog , Salmo salar , Imuno-HistoquímicaRESUMO
The infectious pancreatic necrosis (IPNV) is the causative agent of an acute illness well characterized in salmonids worldwide. Clinical signs and mortality rates are dependent on several factors such as the viral dose, the age of the fish, the water temperature, among others. An experimental study was conducted to measure the effect of temperature on the gene expression profile of IFN-1(α), STAT-1 and Mx-1 in rainbow trout fry, exposed to IPNV. Fry (n=198) were exposed at 8, 12 and 16°C, and samples were taken for 21 days to determine the virus titer and gene expression. In the first 11 days the greatest viral titer was recorded at 8°C compared with the values obtained at 12 and 16°C. At 8°C, there was a significant increase on day 4 of mRNA Mx-1 (t-test, p<0.05), time in which the viral titer began to decrease. Furthermore, as the viral titer increased, STAT-1 and Mx-1 (r=0.91) and (r=0.96) increased, respectively. The animals were able to recover from day 4 from some of the symptoms of IPN. Clinical disease was developed only in fish exposed to 12°C and all died between days 6 and 14, despite the highly significant increase shown in the average expression level of Mx-1, compared with the values recorded at 8°C and 16°C (Tukey, p<0.0001). Additionally, the expression profiles of IFN-1(α) and STAT-1 decreased completely (~0.016) and (~0.020 times) on day 7. The highest expression level of IFN-1(α), occurred at 16°C (Tukey, p<0.0005). Fry exposed at 16°C were normal during the experiment. IFN-1(α) possibly generated a protector effect from day 2 when they showed a significant expression increase compared with the results at 8°C and 12°C (t-student, p<0.0001); however, STAT-1 was not significantly affected by temperature, although the highest average expression value was recorded at 16°C. Our research supports the expression of relevant anti-viral response genes as IFN-1(α), STAT-1 and Mx-1 are physiologically modulated by the water temperature, directly influencing the development of the IPN disease in rainbow trout.
El virus de la necrosis pancreática infecciosa (IPNV) es el agente etiológico de una enfermedad aguda bien caracterizada en salmónidos alrededor del mundo. Los signos clínicos y la tasa de mortalidad dependen de varios factores tales como la dosis viral, la edad del pez y la temperatura del agua, entre otros. Un estudio experimental se llevó a cabo para medir el efecto de la temperatura sobre el perfil de expresión génica de IFN-1(α), STAT-1 y Mx-1 en alevines de trucha arcoíris expuestos con IPNV. Los alevines (n=198) fueron expuestos a 8, 12 y 16°C, y se tomaron muestras durante 21 días para determinar el título viral y la expresión génica. En los primeros 11 días el mayor titulo viral se registró a 8ºC en comparación con 12 y 16. A 8°C, existió un incremento significativo en el día 4 del ARNm de Mx-1 (t-test, p<0.05), momento en que el título viral empezó a disminuir. Además conforme el título viral aumentaba, también STAT-1 y Mx-1 aumentaron (r=0.91) y (r=0.96) respectivamente. Los animales fueron capaces de recuperarse desde el día 4 de algunos de los síntomas de IPN. La enfermedad clínica se desarrolló únicamente en peces expuestos a 12°C y todos murieron entre el día 6 y 14, a pesar del incremento altamente significativo mostrado en el nivel promedio de expresión de Mx-1 a 12°C, comparados con los valores registrados a 8 y 16°C (Tukey, p<0.0001). Además los perfiles de expresión de IFN-1(α) y STAT-1 decrecieron el día 7 completamente (~0.016) y (~0.020) veces, respectivamente. El nivel de expresión promedio más alto de IFN-1(α) se registró a 16°C (Tukey, p<0.0005). Los alevines expuestos a 16°C se mostraron normales durante el experimento. IFN-1(α) posiblemente generó un efecto protector desde el día 2 cuando mostró un aumento significativo en comparación con los resultados a 8 y 12°C (t-student, p<0.0001); sin embargo, STAT-1 no fue afectado de manera significativa por la temperatura, aunque el más alto valor de expresión promedio se registró a 16°C. Nuestra investigación confirma que la expresión de genes relevantes de respuesta antiviral como IFN-1(α), STAT-1 y Mx-1 son fisiológicamente modulados por la temperatura del agua, influyendo directamente en el desarrollo de la enfermedad de IPN en trucha arcoíris.
Assuntos
Animais , Temperatura , Truta/anormalidades , Vírus da Necrose Pancreática InfecciosaRESUMO
The tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) ia a native fish of the Amazon Basin. It is a rheophilic species, and in captivity the reproduction occurs only through hormonal induction. Larvae of native species require more attention in the first stages, so the first feeding has great importance for the fry production and survival. Throughout the development, the larvae of tambaqui undergo morphological and physiological changes and eating habits. The objective of this study was to evaluate the use of different diets on the first feeding tambaqui larvae. Tambaqui larvae were grown during 20 days under the following dietary treatments: plankton; plankton + ration; selected plankton; selected plankton + ration; and ration. The feed was given twice daily, "ad libitum". The physic-chemical variables of water remained in limits accepted for the species. Treatments where it was used live food resulted in better growth performance of tambaqui larvae. The addition of ration associated with the live food to feed the tambaqui larvae also improved performance, although ration is not recommended as the sole food source, in the first days of life. Therefore, the use of live food plus ration, from the third day of exogenous feeding, improves a better growth performance and survival of tambaqui larvae.
O tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) nativo da Bacia Amazônica. É uma espécie reofílica que em cativeiro se reproduz somente através da indução hormonal. Sendo a larvicultura de espécies nativas uma das fases que exige maior atenção, o início da alimentação exógena exerce grande importância para a produção e sobrevivência de alevinos. Ao longo do desenvolvimento, as larvas de tambaqui passam por modificações morfo-fisiológicas e no hábito alimentar. O objetivo deste trabalho foi avaliar a utilização de diferentes dietas na primeira alimentação de larvas de tambaqui. As larvas de tambaqui foram cultivadas durante 20 dias, sob os seguintes tratamentos alimentares: plâncton; plâncton + ração; plâncton selecionado; plâncton selecionado + ração; e ração. A alimentação foi oferecida duas vezes ao dia, ad libitum. As variáveis físico-químicas mantiveram-se em limites aceitos para a espécie. Os tratamentos que utilizaram o emprego de alimentos vivos resultaram em melhor desempenho produtivo das larvas de tambaqui. A adição da ração associada ao alimento vivo na alimentação das larvas de tambaqui também melhorou o desempenho, embora esta não seja indicada como única fonte alimentar, nos primeiros dias de vida. Portanto, o emprego de alimento vivo acrescido de ração, a partir do terceiro dia de alimentação exógena
Assuntos
Animais , Characidae/crescimento & desenvolvimento , Characidae/metabolismo , Ração Animal , Ração Animal/análiseRESUMO
The tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) ia a native fish of the Amazon Basin. It is a rheophilic species, and in captivity the reproduction occurs only through hormonal induction. Larvae of native species require more attention in the first stages, so the first feeding has great importance for the fry production and survival. Throughout the development, the larvae of tambaqui undergo morphological and physiological changes and eating habits. The objective of this study was to evaluate the use of different diets on the first feeding tambaqui larvae. Tambaqui larvae were grown during 20 days under the following dietary treatments: plankton; plankton + ration; selected plankton; selected plankton + ration; and ration. The feed was given twice daily, "ad libitum". The physic-chemical variables of water remained in limits accepted for the species. Treatments where it was used live food resulted in better growth performance of tambaqui larvae. The addition of ration associated with the live food to feed the tambaqui larvae also improved performance, although ration is not recommended as the sole food source, in the first days of life. Therefore, the use of live food plus ration, from the third day of exogenous feeding, improves a better growth performance and survival of tambaqui larvae.
O tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) nativo da Bacia Amazônica. É uma espécie reofílica que em cativeiro se reproduz somente através da indução hormonal. Sendo a larvicultura de espécies nativas uma das fases que exige maior atenção, o início da alimentação exógena exerce grande importância para a produção e sobrevivência de alevinos. Ao longo do desenvolvimento, as larvas de tambaqui passam por modificações morfo-fisiológicas e no hábito alimentar. O objetivo deste trabalho foi avaliar a utilização de diferentes dietas na primeira alimentação de larvas de tambaqui. As larvas de tambaqui foram cultivadas durante 20 dias, sob os seguintes tratamentos alimentares: plâncton; plâncton + ração; plâncton selecionado; plâncton selecionado + ração; e ração. A alimentação foi oferecida duas vezes ao dia, "ad libitum". As variáveis físico-químicas mantiveram-se em limites aceitos para a espécie. Os tratamentos que utilizaram o emprego de alimentos vivos resultaram em melhor desempenho produtivo das larvas de tambaqui. A adição da ração associada ao alimento vivo na alimentação das larvas de tambaqui também melhorou o desempenho, embora esta não seja indicada como única fonte alimentar, nos primeiros dias de vida. Portanto, o emprego de alimento vivo acrescido de ração, a partir do terceiro dia de alimentação exógena, proporciona melhor desempenho produtivo e sobrevivência de larvas de tambaqui.
RESUMO
The tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) ia a native fish of the Amazon Basin. It is a rheophilic species, and in captivity the reproduction occurs only through hormonal induction. Larvae of native species require more attention in the first stages, so the first feeding has great importance for the fry production and survival. Throughout the development, the larvae of tambaqui undergo morphological and physiological changes and eating habits. The objective of this study was to evaluate the use of different diets on the first feeding tambaqui larvae. Tambaqui larvae were grown during 20 days under the following dietary treatments: plankton; plankton + ration; selected plankton; selected plankton + ration; and ration. The feed was given twice daily, "ad libitum". The physic-chemical variables of water remained in limits accepted for the species. Treatments where it was used live food resulted in better growth performance of tambaqui larvae. The addition of ration associated with the live food to feed the tambaqui larvae also improved performance, although ration is not recommended as the sole food source, in the first days of life. Therefore, the use of live food plus ration, from the third day of exogenous feeding, improves a better growth performance and survival of tambaqui larvae.(AU)
O tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) nativo da Bacia Amazônica. É uma espécie reofílica que em cativeiro se reproduz somente através da indução hormonal. Sendo a larvicultura de espécies nativas uma das fases que exige maior atenção, o início da alimentação exógena exerce grande importância para a produção e sobrevivência de alevinos. Ao longo do desenvolvimento, as larvas de tambaqui passam por modificações morfo-fisiológicas e no hábito alimentar. O objetivo deste trabalho foi avaliar a utilização de diferentes dietas na primeira alimentação de larvas de tambaqui. As larvas de tambaqui foram cultivadas durante 20 dias, sob os seguintes tratamentos alimentares: plâncton; plâncton + ração; plâncton selecionado; plâncton selecionado + ração; e ração. A alimentação foi oferecida duas vezes ao dia, ad libitum. As variáveis físico-químicas mantiveram-se em limites aceitos para a espécie. Os tratamentos que utilizaram o emprego de alimentos vivos resultaram em melhor desempenho produtivo das larvas de tambaqui. A adição da ração associada ao alimento vivo na alimentação das larvas de tambaqui também melhorou o desempenho, embora esta não seja indicada como única fonte alimentar, nos primeiros dias de vida. Portanto, o emprego de alimento vivo acrescido de ração, a partir do terceiro dia de alimentação exógena(AU)
Assuntos
Animais , Characidae/crescimento & desenvolvimento , Characidae/metabolismo , Ração Animal/análise , Ração AnimalRESUMO
The tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) ia a native fish of the Amazon Basin. It is a rheophilic species, and in captivity the reproduction occurs only through hormonal induction. Larvae of native species require more attention in the first stages, so the first feeding has great importance for the fry production and survival. Throughout the development, the larvae of tambaqui undergo morphological and physiological changes and eating habits. The objective of this study was to evaluate the use of different diets on the first feeding tambaqui larvae. Tambaqui larvae were grown during 20 days under the following dietary treatments: plankton; plankton + ration; selected plankton; selected plankton + ration; and ration. The feed was given twice daily, "ad libitum". The physic-chemical variables of water remained in limits accepted for the species. Treatments where it was used live food resulted in better growth performance of tambaqui larvae. The addition of ration associated with the live food to feed the tambaqui larvae also improved performance, although ration is not recommended as the sole food source, in the first days of life. Therefore, the use of live food plus ration, from the third day of exogenous feeding, improves a better growth performance and survival of tambaqui larvae.
O tambaqui Colossoma macropomum (Cuvier, 1818) (Characiformes: Characidae) nativo da Bacia Amazônica. É uma espécie reofílica que em cativeiro se reproduz somente através da indução hormonal. Sendo a larvicultura de espécies nativas uma das fases que exige maior atenção, o início da alimentação exógena exerce grande importância para a produção e sobrevivência de alevinos. Ao longo do desenvolvimento, as larvas de tambaqui passam por modificações morfo-fisiológicas e no hábito alimentar. O objetivo deste trabalho foi avaliar a utilização de diferentes dietas na primeira alimentação de larvas de tambaqui. As larvas de tambaqui foram cultivadas durante 20 dias, sob os seguintes tratamentos alimentares: plâncton; plâncton + ração; plâncton selecionado; plâncton selecionado + ração; e ração. A alimentação foi oferecida duas vezes ao dia, "ad libitum". As variáveis físico-químicas mantiveram-se em limites aceitos para a espécie. Os tratamentos que utilizaram o emprego de alimentos vivos resultaram em melhor desempenho produtivo das larvas de tambaqui. A adição da ração associada ao alimento vivo na alimentação das larvas de tambaqui também melhorou o desempenho, embora esta não seja indicada como única fonte alimentar, nos primeiros dias de vida. Portanto, o emprego de alimento vivo acrescido de ração, a partir do terceiro dia de alimentação exógena, proporciona melhor desempenho produtivo e sobrevivência de larvas de tambaqui.
RESUMO
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.
Assuntos
Conservação dos Recursos Naturais/métodos , Pesqueiros , Peixes , Animais , Pesqueiros/legislação & jurisprudência , Água Doce , MéxicoRESUMO
The preservation of the genetic variability of hatchery stocks used to supplement natural populations is a priority. Current study employed RAPD markers to examine the genetic diversity of dourado samples from the middle Paranapanema river and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPD primers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentage of polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. The genetic diversity was lower in the broodstock than in natural population. Amova results showed that most inter-population genetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate genetic differentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks were mixed and analyzed as a single population (FST = 0.07). Instead of releasing each lot separately into the water, mixing specimens produced in the various fry stocks before releasing them in the river would be more feasible. The restocked population will have a genetic structure closer to natural populations.(AU)
Conservar a variabilidade genética dos estoques de alevinos de peixes para suplementar populações naturais é uma prioridade. O objetivo deste estudo foi examinar a diversidade genética por meio dos marcadores de RAPD de amostras de peixes reprodutores de dourado do médio Paranapanema (população natural) e alevinos usados no programa de repovoamento da estação de aquicultura da UHE de Salto Grande. Foram analisados 19 primers de RAPD, que geraram 299 bandas, as quais foram utilizadas para as análises genéticas. A porcentagem de fragmentos polimórficos foi mais elevada na população natural do que nos estoques. A diversidade genética também foi mais baixa nos alevinos. Os resultados da Amova mostraram que a maior parte de variação genética interpopulacional está dentro dos estoques (83,9%) e não entre eles (16,1%). Foi observada uma diferenciação genética moderada (FST = 0.16). Esta diferenciação diminuiu quando os quatro estoques de alevinos eram misturados e analisados como uma única população (FST = 0.07). Em vez de liberar cada lote separadamente no ambiente, seria melhor misturar todos os indivíduos produzidos nos vários estoques de alevinos antes de liberá-los no rio. Desta maneira, a população reintroduzida terá uma estrutura genética mais perto da população natural.(AU)
Assuntos
Animais , Caraciformes/genética , Marcadores Genéticos , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
The preservation of the genetic variability of hatchery stocks used to supplement natural populations is a priority. Current study employed RAPD markers to examine the genetic diversity of dourado samples from the middle Paranapanema river and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPD primers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentage of polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. The genetic diversity was lower in the broodstock than in natural population. Amova results showed that most inter-population genetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate genetic differentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks were mixed and analyzed as a single population (FST = 0.07). Instead of releasing each lot separately into the water, mixing specimens produced in the various fry stocks before releasing them in the river would be more feasible. The restocked population will have a genetic structure closer to natural populations.
Conservar a variabilidade genética dos estoques de alevinos de peixes para suplementar populações naturais é uma prioridade. O objetivo deste estudo foi examinar a diversidade genética por meio dos marcadores de RAPD de amostras de peixes reprodutores de dourado do médio Paranapanema (população natural) e alevinos usados no programa de repovoamento da estação de aquicultura da UHE de Salto Grande. Foram analisados 19 primers de RAPD, que geraram 299 bandas, as quais foram utilizadas para as análises genéticas. A porcentagem de fragmentos polimórficos foi mais elevada na população natural do que nos estoques. A diversidade genética também foi mais baixa nos alevinos. Os resultados da Amova mostraram que a maior parte de variação genética interpopulacional está dentro dos estoques (83,9%) e não entre eles (16,1%). Foi observada uma diferenciação genética moderada (FST = 0.16). Esta diferenciação diminuiu quando os quatro estoques de alevinos eram misturados e analisados como uma única população (FST = 0.07). Em vez de liberar cada lote separadamente no ambiente, seria melhor misturar todos os indivíduos produzidos nos vários estoques de alevinos antes de liberá-los no rio. Desta maneira, a população reintroduzida terá uma estrutura genética mais perto da população natural.
Assuntos
Animais , Caraciformes/genética , Marcadores Genéticos , Técnica de Amplificação ao Acaso de DNA PolimórficoRESUMO
The preservation of the genetic variability of hatchery stocks used to supplement natural populations is a priority. Current study employed RAPD markers to examine the genetic diversity of dourado samples from the middle Paranapanema river and from the broodstock used in the stock enhancement program of the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPD primers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentage of polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. The genetic diversity was lower in the broodstock than in natural population. Amova results showed that most inter-population genetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate genetic differentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks were mixed and analyzed as a single population (FST = 0.07). Instead of releasing each lot separately into the water, mixing specimens produced in the various fry stocks before releasing them in the river would be more feasible. The restocked population will have a genetic structure closer to natural populations.
The preservation of the genetic variability of hatchery stocks used to supplement naturalpopulations is a priority. Current study employed RAPD markers to examine the genetic diversity of douradosamples from the middle Paranapanema river and from the broodstock used in the stock enhancement programof the Aquaculture and Hydrobiology Station at the Salto Grande Hydroelectric Power Plant. Nineteen RAPDprimers were analyzed, which generated 299 bands and the latter were used for genetic analysis. The percentageof polymorphic fragments was higher in stock captured in the Paranapanema river than from fry stocks. Thegenetic diversity was lower in the broodstock than in natural population. Amova results showed that most interpopulationgenetic variation lay within stocks (83.9%) and not between them (16.1%). Moderate geneticdifferentiation (FST = 0.16) was reported. Nevertheless, differentiation decreased when the four fry stocks weremixed and analyzed as a single population (FST = 0.07). Instead of releasing each lot separately into the water,mixing specimens produced in the various fry stocks before releasing them in the river would be more feasible.The restocked population will have a genetic structure closer to natural populations.