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
Metais Pesados , Oligoelementos , Poluentes Químicos da Água , Animais , Brasil , Cádmio , Monitoramento Ambiental/métodos , Peixes , Sedimentos Geológicos , Lagos , Chumbo , Metais Pesados/análise , Rios , Oligoelementos/análise , Água , Poluentes Químicos da Água/análiseRESUMO
This study analyzed the diet during early developmental stages of Astyanax lacustris (AA),Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) and Prochilodus lineatus (PL), under experimentalconditions. Fish larvae, 350 of each species, were stocked separately in 16 fiber-cement tanks (500 L), fromwhich, three larvae of each species were collected every three days, for 36 days. Tanks were fertilized (1.5 gNPK-7: 14: 8) and had 50% of the surface with macrophytes. Larvae were grouped in age classes = I: 5 to11, II: 14 to 20, III: 23 to 29 and IV: 32 to 38 days and, dissected for analysis of the digestive tract.Methodologies of dominance, frequency of occurrence and points of food items were used. For AA andPM larvae, measurements were taken for the number and size of organisms to determine the percentparticipation in biovolume. Changes in diets of larvae in different age classes were found as well as betweendifferent species, with the same age. Rotifers were dominant in the content of digestive tracts of all speciesat Class I, and the larvae diets became more distinct with increasing age, in which AA consumed mainlyrotifers, PM, larger organisms (mainly cladocerans), PL, algae (diatoms as the main item) and PP with amore diversified diet (rotifers, ostracodes and algae). In conclusion, early stages of these species presenteddistinct diets, undergoing remarkable changes in the first 38 days of life.(AU)
Estudou-se a alimentação dos estágios iniciais de desenvolvimento de Astyanax lacustris (AA),Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) e Prochilodus lineatus (PL) em condiçõesexperimentais. As larvas, 350 cada espécie, foram estocadas separadamente, em 16 tanques de fibrocimento(500 L) dos quais foram coletados três indivíduos de cada um, a cada três dias, por 36 dias. Os tanquesforam fertilizados (1,5 g de NPK-7:14:8) e tinham 50% da superfície com macrófitas. As larvas foramagrupadas em classes de idade = I: 5 a 11, II: 14 a 20, III: 23 a 29 e IV: 32 a 38 dias e, dissecadas para aabertura do trato digestório. Foram empregadas as metodologias de dominância, frequência de ocorrência epontos dos itens alimentares. Para as larvas de AA e PM, foram contados e tomadas medidas das dimensõesdos organismos para determinar a participação percentual do biovolume. Observaram-se mudanças nasdietas das larvas em diferentes classes de idade e também entre larvas de espécies diferentes, com mesmaidade. Houve predomínio de rotíferos nos conteúdos dos tratos digestórios de todas as espécies na classe I,as dietas das larvas passaram a ser mais distintas com o incremento da idade, com AA consumindoprincipalmente rotíferos, PM organismos maiores (principalmente cladóceros), PL tendo algas(diatomáceas como item principal) e PP com uma dieta mais variada (rotíferos, ostracodes e algas).Conclui-se que as formas jovens destas espécies apresentaram dietas distintas, passando por nítidasalterações nos primeiros 38 dias de vida.(AU)
Assuntos
Animais , Caraciformes/crescimento & desenvolvimento , Caraciformes/metabolismo , Ração Animal/análise , Peixes/crescimento & desenvolvimentoRESUMO
This study analyzed the diet during early developmental stages of Astyanax lacustris (AA), Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) and Prochilodus lineatus (PL), under experimental conditions. Fish larvae, 350 of each species, were stocked separately in 16 fiber-cement tanks (500 L), from which, three larvae of each species were collected every three days, for 36 days. Tanks were fertilized (1.5 g NPK-7: 14: 8) and had 50% of the surface with macrophytes. Larvae were grouped in age classes = I: 5 to 11, II: 14 to 20, III: 23 to 29 and IV: 32 to 38 days and, dissected for analysis of the digestive tract. Methodologies of dominance, frequency of occurrence and points of food items were used. For AA and PM larvae, measurements were taken for the number and size of organisms to determine the percent participation in biovolume. Changes in diets of larvae in different age classes were found as well as between different species, with the same age. Rotifers were dominant in the content of digestive tracts of all species at Class I, and the larvae diets became more distinct with increasing age, in which AA consumed mainly rotifers, PM, larger organisms (mainly cladocerans), PL, algae (diatoms as the main item) and PP with a more diversified diet (rotifers, ostracodes and algae) . In conclusion, early stages of these species presented distinct diets, undergoing remarkable changes in the first 38 days of life.
Estudou-se a alimentação dos estágios iniciais de desenvolvimento de Astyanax lacustris (AA), Piaractus mesopotamicus (PM), Megaleporinus obtusidens (MO) e Prochilodus lineatus (PL) em condições experimentais. As larvas, 350 cada espécie, foram estocadas separadamente, em 16 tanques de fibrocimento (500 L) dos quais foram coletados três indivíduos de cada um, a cada três dias, por 36 dias. Os tanques foram fertilizados (1,5 g de NPK-7:14:8) e tinham 50% da superfície com macrófitas. As larvas foram agrupadas em classes de idade = I: 5 a 11, II: 14 a 20, III: 23 a 29 e IV: 32 a 38 dias e, dissecadas para a abertura do trato digestório. Foram empregadas as metodologias de dominância, frequência de ocorrência e pontos dos itens alimentares. Para as larvas de AA e PM, foram contados e tomadas medidas das dimensões dos organismos para determinar a participação percentual do biovolume. Observaram-se mudanças nas dietas das larvas em diferentes classes de idade e também entre larvas de espécies diferentes, com mesma idade. Houve predomínio de rotíferos nos conteúdos dos tratos digestórios de todas as espécies na classe I, as dietas das larvas passaram a ser mais distintas com o incremento da idade, com AA consumindo principalmente rotíferos, PM organismos maiores (principalmente cladóceros), PL tendo algas (diatomáceas como item principal) e PP com uma dieta mais variada (rotíferos, ostracodes e algas). Conclui-se que as formas jovens destas espécies apresentaram dietas distintas, passando por nítidas alterações nos primeiros 38 dias de vida.