RESUMO

The concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn (TE) in four juvenile fishes (Acestrorhynchus pantaneiro, Salminus brasiliensis, Brycon orbignyanus, and Megaleporinus obtusidens) and associated sediment water from the Lower Paraná River were measured. For muscle, gills, and liver fishes, the TE accumulation in the muscle, gills, and liver was evaluated. The TE concentration was measured by quadrupolar inductively coupled plasma mass spectrometry (Q-ICP-MS). Cadmium (0.25 ± 0.07 µg L-1), Cu (3.00 ± 1.44 µg L-1), Fe (612 ± 69 µg L-1), and Pb (1.92 ± 1.20 µg L-1) in water and As (4.1-6.9 µg g-1), Cr (20.1-31.4 µg g-1), Cu (10.7-19.2 µg g-1), Mn (351.3-482.2 µg g-1), and Ni (24.5 ± 10.9 µg g-1) in sediments exceeded the guide values for the conservation of aquatic life. In general, muscle of omnivorous species (B. orbignyanus and M. obtusidens) showed higher values of elements than those of carnivorous species (A. pantaneiro and S. brasiliensis). However, TE concentrations varied with fish species and organs. Independently of the examined species, the highest concentrations of Cr and Pb were in the muscle and gills, respectively. Cadmium, Cu, and Fe concentrations were higher in the liver than in gills and muscle in all four fish species. These results were consistent with the tissue selectivity index analyzed. For the four species, major essential elements showed the highest accumulation. However, the accumulation of toxic elements in omnivorous fish was higher than in carnivorous fish. The individual pollution load index indicated that sediment was very polluted with As and Pb, but based on the combined ecological indexes, low elemental sediment pollution in the Espinillo Lake was revealed.

Assuntos

RESUMO

In regions where there is intense polluting activity, a greater availability of metals in water impounded by dams increases the availability and contamination of the fauna and flora. Thus, we assessed the accumulation of metals in muscle and gills of fish of different trophic levels in the area of influence of Foz do Chapecó hydroelectric plant on the Uruguai river. We analyzed the metals Pb, Cd, Cu, Cr, Mn, Zn, and Fe in Hypostomus isbrueckeri (cascudo), Pimelodus maculatus (mandi), and Salminus brasiliensis (dourado). We collected specimens from both upstream and downstream of the reservoir in February and March 2014. We also measured the allometric condition factor of the fish to determine their physiological status. Physical and chemical variables of the water were measured to determine the influence of these abiotic variables on the bioavailability of metals and on the condition factor of the fish. Gills had a higher concentration of metals than muscle. Hypostomus isbrueckeri and Pimelodus maculatus possessed high concentrations of metals, indicating greater bioaccumulation in benthic species. Only chromium in muscle varied significantly between upstream and downstream, with higher concentrations in H. isbrueckeri and P. maculatus upstream. Chromium contamination, however, did not change the condition factor, which did not vary between upstream and downstream for any of the studied species. We found no influence of abiotic variables of the water on the bioavailability of the metals in the environment. Although the data do not indicate trophic magnification, the different species react differently to environmental changes and their trophic plasticity makes it difficult to assign them to specific guilds.

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RESUMO

Salminus brasiliensis is a potamodromous fish species that occurs in southern South American rivers. In spite of its ecological and economic relevance, information regarding the reproductive biology of S. brasiliensis is still scarce. This study used data from 18 years of continuous sampling in the Upper Uruguay River Basin, analyzing 718 adult fish (307 males, 243 females, 168 undefined) captured at different months of the year. The results showed that the reproductive timing for S. brasiliensis is wide in the Upper Uruguay River, with the occurrence of mature fish between the month of August and March and spawned individuals between July and May of the next year. These results were sustained by the increase of gonadal somatic relationship (GSR) from August. The reproductive timing of S. brasiliensis in the Upper Uruguay River may start between the middle winter and early spring (from late July to late September), and may extend until the late summer and middle fall (from the middle February to early May). These findings contribute to information on the general biology of S. brasiliensis and provide valuable knowledge to management programs and to conservation efforts of this fisheries resource.(AU)

Salminus brasiliensis é uma espécie potamodroma que ocorre em rios da América do Sul. Apesar de sua importância ecológica e econômica, informações sobre a biologia reprodutiva de S. brasiliensis ainda são escassas. O presente estudo utilizou dados de 18 anos de amostragens contínuas na bacia do alto rio Uruguai, analisando 718 peixes adultos (307 machos, 243 fêmeas, 168 indefinidos) capturados em diferentes meses do ano. Os resultados mostraram que o período reprodutivo de S. brasiliensis é amplo na bacia do alto rio Uruguai, com a ocorrência de peixes maduros entre agosto e março, e de peixes desovados entre os meses de julho e maio do ano seguinte. A relação gonadossomática reforça essa observação, pois mostra um aumento a partir de agosto. O período reprodutivo de S. brasiliensis no alto rio Uruguai pode iniciar entre meados do inverno e início da primavera (entre final de julho e final de setembro), podendo se estender até o final do verão e meados do outono (entre meados de fevereiro e início de maio). Essas descobertas contribuem com informações sobre a biologia geral de S. brasiliensis e são relevantes para programas de gestão e para esforços de conservação desse recurso pesqueiro.(AU)

Assuntos

RESUMO

Salminus brasiliensis is a potamodromous fish species that occurs in southern South American rivers. In spite of its ecological and economic relevance, information regarding the reproductive biology of S. brasiliensis is still scarce. This study used data from 18 years of continuous sampling in the Upper Uruguay River Basin, analyzing 718 adult fish (307 males, 243 females, 168 undefined) captured at different months of the year. The results showed that the reproductive timing for S. brasiliensis is wide in the Upper Uruguay River, with the occurrence of mature fish between the month of August and March and spawned individuals between July and May of the next year. These results were sustained by the increase of gonadal somatic relationship (GSR) from August. The reproductive timing of S. brasiliensis in the Upper Uruguay River may start between the middle winter and early spring (from late July to late September), and may extend until the late summer and middle fall (from the middle February to early May). These findings contribute to information on the general biology of S. brasiliensis and provide valuable knowledge to management programs and to conservation efforts of this fisheries resource.(AU)

Salminus brasiliensis é uma espécie potamodroma que ocorre em rios da América do Sul. Apesar de sua importância ecológica e econômica, informações sobre a biologia reprodutiva de S. brasiliensis ainda são escassas. O presente estudo utilizou dados de 18 anos de amostragens contínuas na bacia do alto rio Uruguai, analisando 718 peixes adultos (307 machos, 243 fêmeas, 168 indefinidos) capturados em diferentes meses do ano. Os resultados mostraram que o período reprodutivo de S. brasiliensis é amplo na bacia do alto rio Uruguai, com a ocorrência de peixes maduros entre agosto e março, e de peixes desovados entre os meses de julho e maio do ano seguinte. A relação gonadossomática reforça essa observação, pois mostra um aumento a partir de agosto. O período reprodutivo de S. brasiliensis no alto rio Uruguai pode iniciar entre meados do inverno e início da primavera (entre final de julho e final de setembro), podendo se estender até o final do verão e meados do outono (entre meados de fevereiro e início de maio). Essas descobertas contribuem com informações sobre a biologia geral de S. brasiliensis e são relevantes para programas de gestão e para esforços de conservação desse recurso pesqueiro.(AU)

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RESUMO

The dourado, Salminus brasiliensis (Cuvier, 1816) is a freshwater piscivorous Characin native to South American rivers. Owing to the high quality of its flesh and its fast growth, it is the object of both capture fisheries and fish farming. However, very little is known about the endocrine regulation of feeding and metabolism of dourado. In this study, cDNAs for orexin, CART and CCK were isolated in dourado, and their mRNA tissue distributions examined. In order to assess the role of these peptides in the regulation of feeding of dourado, the effects of fasting and feeding on mRNA expression levels of orexin, CART and CCK in the brain as well as CCK in the intestine were assessed. Whereas orexin and CCK have widespread mRNA distributions in the brain and peripheral organs, CART seems to be mostly limited to the brain. Orexin brain expression increased with fasting and displayed periprandial changes, suggesting it is involved in both long- and short-term regulation of feeding and appetite. CART and CCK hypothalamic expressions were not affected by fasting, but displayed periprandial changes with post-feeding decreases, suggesting roles in short-term satiation. CCK expression in the anterior intestine was not affected by fasting and did not display periprandial changes. Overall, our results suggest that orexin, CART and CCK are involved in the physiology of feeding of dourado.

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RESUMO

Objective. The aim of this study was evaluate the genetic diversity of the following broodstocks: piapara (Leporinus elongatus), dourado (Salminus brasiliensis), jundiá (Rhamdia quelen) and cachara (Pseudoplatystoma fasciatum) already useful for restocking programs in the Paranapanema, Iguaçu and Paraná Brazilian Rivers. Materials and methods. Samples from the caudal fin of 122 fish were analyzed. DNA was extracted by NaCl protocol. PCR products were separated by a horizontal agarose gel electrophoresis. The fragments were visualized by staining with ethidium bromide. Results. The amplification of 25 primers generated different fragments in studied species that allowed characterizing 440 fragments of 100-2900 bp. High percentage of polymorphic fragments (66.67 to 86.29), Shannon index (0.365 to 0.486) and genetic diversity of Nei (0.248 to 0.331) were detected. Conclusions. The level of genetic variability in the broodstocks was adequate for allowing their use in restocking programs in the studied Rivers. However, periodical monitoring studies of genetic variability in these stocks, the mating system, reproductive system and general management must be made to guarantee the preservation of wild populations.

Objetivo. El objetivo de este estudio fue evaluar la diversidad genética de los siguientes lotes de reproductores: piapara (Leporinus elongatus), dourado (Salminus brasiliensis), jundiá (Rhamdia quelen) y cachara (Pseudoplatystoma fasciatum) utilizados para programas de repoblación en los ríos brasileños Paranapanema, Iguaçu y Paraná. Materiales y métodos. Muestras de aleta caudal de 122 peces fueron analizadas. El ADN fue extraído por el protocolo de NaCl. Los productos de PCR fueron separados por electroforesis horizontal en gel de agarosa. Los fragmentos fueron visualizados por marcación con bromuro de etidio. Resultados. La amplificación de los 25 iniciadores produjo diferentes fragmentos en las especies estudiadas que permitieron caracterizar 440 fragmentos de 100 a 2900 pb. Fueron detectados un alto porcentaje de fragmentos polimórficos (66.67 a 86.29), de índice de Shannon (0.365 a 0.486) y de diversidad genética de Nei (0.248 a 0.331). Conclusiones. El nivel de variabilidad genética en los lotes de reproductores fue adecuado para su utilización en programas de repoblación en los ríos estudiados. Sin embargo, estudios de monitoreo periódico de la variabilidad genética en esos lotes, del sistema de cruzamiento, del sistema reproductivo y del manejo general deben ser realizados para garantizar la preservación de las populaciones naturales.

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RESUMO

Fish larvae and adults are morphologically distinct from each other and have different ecological requirements. Research on the dynamics of ichthyoplankton provides valuable information about the early stages of the life cycle of fish. This study analyzed the temporal and spatial distribution of the larval stages of three migratory species - Salminus brasiliensis (Cuvier, 1816), Prochilodus lineatus (Valenciennes, 1836) and Pseudoplatystoma corruscans (Agassiz, 1829) - to identify possible spawning areas in the last lotic remnant of the upper Paraná River, in the Brazilian territory. A total of 26 points were sampled monthly from October 2003 to November 2004. The PERMANOVA detected significant differences between the months only for S. brasiliensis (Pseudo-F = 3.88, p = 0.0021) and P. corruscans (Pseudo-F = 3.35, p = 0.004). Among the environmental variables, temperature was the most important and the Mantel test detected a significant correlation between temperature and the densities, only for P. lineatus (r = 0.09, p = 0.03). The species in our data chose for spawning tributaries that are not dammed, of which most are outside conservation areas. Therefore, recruitment, maintenance and possible actions aiming to recover the stocks of these species are dependent on the conservation of tributaries and floodplain lakes in the region, in addition to monitoring to prevent fishing during the reproductive period.(AU)

Assuntos

RESUMO

Fish larvae and adults are morphologically distinct from each other and have different ecological requirements. Research on the dynamics of ichthyoplankton provides valuable information about the early stages of the life cycle of fish. This study analyzed the temporal and spatial distribution of the larval stages of three migratory species - Salminus brasiliensis (Cuvier, 1816), Prochilodus lineatus (Valenciennes, 1836) and Pseudoplatystoma corruscans (Agassiz, 1829) - to identify possible spawning areas in the last lotic remnant of the upper Paraná River, in the Brazilian territory. A total of 26 points were sampled monthly from October 2003 to November 2004. The PERMANOVA detected significant differences between the months only for S. brasiliensis (Pseudo-F = 3.88, p = 0.0021) and P. corruscans (Pseudo-F = 3.35, p = 0.004). Among the environmental variables, temperature was the most important and the Mantel test detected a significant correlation between temperature and the densities, only for P. lineatus (r = 0.09, p = 0.03). The species in our data chose for spawning tributaries that are not dammed, of which most are outside conservation areas. Therefore, recruitment, maintenance and possible actions aiming to recover the stocks of these species are dependent on the conservation of tributaries and floodplain lakes in the region, in addition to monitoring to prevent fishing during the reproductive period.

Assuntos

RESUMO

This study aimed to evaluate whether mate (Ilex paraguariensis A. St. Hil) extract would change lipid and color stability of dourado (Salminus brasiliensis) fillets during frozen storage. Fish fillets were dipped (1 min) in distilled water (control) or in aqueous extract of mate (0.1g mL-1, w/v) and were stored at -7°C for up to 12 months. Conjugated dienes (CD) increased in control fillets after 6 months of storage and then decreased, whereas thiobarbituric acid reactive substances (TBARS) value increased along the whole experimental period. Mate treatment reduced CD and TBARS values of fillets. Dourado fillets tended to yellow along the whole experimental period (average H*= 72.55) Although the mate treatment had increased the yellowness of fillets at the start of storage, this treatment reduced the increase in luminosity (L*) and in yellowness (H*) triggered by frozen storage. Results indicate that mate extract inhibits lipid oxidation and some color changes caused by the frozen storage of fish fillets.

Foi avaliado o efeito do extrato de mate (Ilex paraguariensis A. St. Hil) sobre as alterações lipídicas e de cor de filés de dourado (Salminus brasiliensis) durante o armazenamento congelado. Os filés foram mergulhados (1 min) em água destilada (controle) ou em extrato aquoso de mate (0,1g mL-1, p/v) e armazenados a -7°C por 12 meses. Os dienos conjugados (DC) aumentaram nos filés controle após 6 meses de armazenamento e então diminuíram, enquanto os valores de substâncias reativas ao ácido tiobarbitúrico (TBARS) aumentaram ao longo de todo período experimental. O extrato de mate reduziu os valores de DC e TBARS dos filés. Os filés de dourado tenderam ao amarelo ao longo de todo o período experimental (média do H*=72.55). Ainda que o tratamento com mate tenha aumentado a intensidade de amarelo dos filés no início da armazenagem, esse tratamento reduziu o aumento da luminosidade (L*) e da intensidade de amarelo (H*), promovidos pelo armazenamento congelado. Os resultados indicam que o extrato de mate inibe a oxidação lipídica e algumas alterações de cor decorrentes do congelamento de filés de pescado.

RESUMO

This study aimed to evaluate whether mate (Ilex paraguariensis A. St. Hil) extract would change lipid and color stability of dourado (Salminus brasiliensis) fillets during frozen storage. Fish fillets were dipped (1 min) in distilled water (control) or in aqueous extract of mate (0.1g mL-1, w/v) and were stored at -7°C for up to 12 months. Conjugated dienes (CD) increased in control fillets after 6 months of storage and then decreased, whereas thiobarbituric acid reactive substances (TBARS) value increased along the whole experimental period. Mate treatment reduced CD and TBARS values of fillets. Dourado fillets tended to yellow along the whole experimental period (average H*= 72.55) Although the mate treatment had increased the yellowness of fillets at the start of storage, this treatment reduced the increase in luminosity (L*) and in yellowness (H*) triggered by frozen storage. Results indicate that mate extract inhibits lipid oxidation and some color changes caused by the frozen storage of fish fillets.

Foi avaliado o efeito do extrato de mate (Ilex paraguariensis A. St. Hil) sobre as alterações lipídicas e de cor de filés de dourado (Salminus brasiliensis) durante o armazenamento congelado. Os filés foram mergulhados (1 min) em água destilada (controle) ou em extrato aquoso de mate (0,1g mL-1, p/v) e armazenados a -7°C por 12 meses. Os dienos conjugados (DC) aumentaram nos filés controle após 6 meses de armazenamento e então diminuíram, enquanto os valores de substâncias reativas ao ácido tiobarbitúrico (TBARS) aumentaram ao longo de todo período experimental. O extrato de mate reduziu os valores de DC e TBARS dos filés. Os filés de dourado tenderam ao amarelo ao longo de todo o período experimental (média do H*=72.55). Ainda que o tratamento com mate tenha aumentado a intensidade de amarelo dos filés no início da armazenagem, esse tratamento reduziu o aumento da luminosidade (L*) e da intensidade de amarelo (H*), promovidos pelo armazenamento congelado. Os resultados indicam que o extrato de mate inibe a oxidação lipídica e algumas alterações de cor decorrentes do congelamento de filés de pescado.