RESUMO

The objective of this study was to evaluate the influence of stocking density on the performance of angelfish (Pterophyllum scalare) reared at different densities for 60 days in water tanks containing cages. A completely randomized designed consisting of three treatments (2.33, 4.66 and 9.33 fish/L) and five replicates was adopted, totaling 105 experimental units. The hydrological variables remained within the standards recommended for the species, regardless of stocking density. Stocking density exerted a significant effect (P<0.05) on survival rate (%). In this respect, animals housed at a lower density exhibited higher survival, while an increase in density negatively affected survival rate. There was a significant effect (P<0.05) of treatment on length uniformity and feed conversion. The best productive performance of angelfish (Pterophyllum scalare) including better feed conversion, survival and length and weight uniformity is observed at the lowest stocking density (2.33 fish/L).

Objetivou-se com esse trabalho avaliar a influência da densidade de estocagem no desempenho de Acará-bandeira (Pterophyllum scalare), cultivados em diferentes densidades, por 60 dias, instalados em caixas d ́água contendo gaiolas. O delineamento adotado foi o inteiramente casualizado com três tratamentos de 2,33; 4,66 e 9,33 peixes/L e cinco repetições, total de 105 unidades experimentais. Independente das densidades de estocagem, as variáveis hidrológicas permaneceram dentro dos padrões recomendados para a espécie em estudo. A taxa de sobrevivência (%) apresentou efeito significativo (P<0,05) nas densidades, mostrando que os animais alojados em menor densidade apresentaram sobrevivência mais elevadas. Entretanto, o aumento da densidade afetou negativamente a taxa de sobrevivência. Entre os tratamentos houve efeito significativo (P<0,05) na uniformidade de comprimento e conversão alimentar. O desempenho produtivo do Acará-bandeira (Pterophyllum scalare) com melhor conversão alimentar, sobrevivência e uniformidade de peso e comprimento é na menor densidade de estocagem (2,33 peixes/L).

Assuntos

RESUMO

The objective of this study was to evaluate the influence of stocking density on the performance of angelfish (Pterophyllum scalare) reared at different densities for 60 days in water tanks containing cages. A completely randomized designed consisting of three treatments (2.33, 4.66 and 9.33 fish/L) and five replicates was adopted, totaling 105 experimental units. The hydrological variables remained within the standards recommended for the species, regardless of stocking density. Stocking density exerted a significant effect (P<0.05) on survival rate (%). In this respect, animals housed at a lower density exhibited higher survival, while an increase in density negatively affected survival rate. There was a significant effect (P<0.05) of treatment on length uniformity and feed conversion. The best productive performance of angelfish (Pterophyllum scalare) including better feed conversion, survival and length and weight uniformity is observed at the lowest stocking density (2.33 fish/L).(AU)

Objetivou-se com esse trabalho avaliar a influência da densidade de estocagem no desempenho de Acará-bandeira (Pterophyllum scalare), cultivados em diferentes densidades, por 60 dias, instalados em caixas d ́água contendo gaiolas. O delineamento adotado foi o inteiramente casualizado com três tratamentos de 2,33; 4,66 e 9,33 peixes/L e cinco repetições, total de 105 unidades experimentais. Independente das densidades de estocagem, as variáveis hidrológicas permaneceram dentro dos padrões recomendados para a espécie em estudo. A taxa de sobrevivência (%) apresentou efeito significativo (P<0,05) nas densidades, mostrando que os animais alojados em menor densidade apresentaram sobrevivência mais elevadas. Entretanto, o aumento da densidade afetou negativamente a taxa de sobrevivência. Entre os tratamentos houve efeito significativo (P<0,05) na uniformidade de comprimento e conversão alimentar. O desempenho produtivo do Acará-bandeira (Pterophyllum scalare) com melhor conversão alimentar, sobrevivência e uniformidade de peso e comprimento é na menor densidade de estocagem (2,33 peixes/L).(AU)

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RESUMO

Phenylketonuria (PKU) is the most frequent disturbance of amino acid metabolism being caused by severe deficiency of phenylalanine hydroxylase activity. Untreated PKU patients present severe mental retardation whose pathophysiology is not completely estabilished. Despite the low-Phe diet, a considerable number of phenylketonuric patients present a mild to moderate psychomotor delay and decreased cognitive functions. In the present study we evaluated various parameters of oxidative stress namely thiobarbituric acid-reactive species (TBA-RS), total antioxidant reactivity (TAR) and activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) in two groups of treated PKU patients, one with well controlled and the other with high Phe blood levels in order to investigate whether blood Phe concentrations could be correlated with the extend of oxidative stress. We initially verified a marked increase of TBA-RS, and a decrease of TAR in plasma, as well as a reduction of erythrocyte GSH-Px activity which were similar in both groups of PKU patients, when compared to controls of similar ages. In contrast, CAT and SOD activities were not altered in PKU patients. These results show that oxidative stress occurs in PKU patients and that this pathogenic process is probably not directly correlated to Phe blood levels.

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RESUMO

Phenylketonuria (PKU) is an autossomal recessive disease caused by phenylalanine-4-hydroxylase deficiency, which is a liver-specific enzyme that catalyzes the hydroxylation of l-phenylalanine (Phe) to l-tyrosine (Tyr). The deficiency of this enzyme leads to the accumulation of Phe in the tissues and plasma of patients. The clinical characterization of this disease is mental retardation and other neurological features. The mechanisms of brain damage are poorly understood. Oxidative stress is observed in some inborn errors of intermediary metabolism owing to the accumulation of toxic metabolites leading to excessive free radical production and may be a result of restricted diets on the antioxidant status. In the present study we evaluated various oxidative stress parameters, namely thiobarbituric acid-reactive species (TBA-RS) and total antioxidant reactivity (TAR) in the plasma of PKU patients. The activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) were also measured in erythrocytes from these patients. It was observed that phenylketonuric patients present a significant increase of plasma TBA-RS measurement, indicating a stimulation of lipoperoxidation, as well as a decrease of plasma TAR, reflecting a deficient capacity to rapidly handle an increase of reactive species. The results also showed a decrease of erythrocyte GSH-Px activity. Therefore, it is presumed that oxidative stress is involved in the pathophysiology of the tissue damage found in PKU.

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X-linked adrenoleukodystrophy (X-ALD) is a hereditary disorder of peroxisomal metabolism biochemically characterized by the accumulation of very long chain fatty acids (VLCFA), particularly hexacosanoic acid (C26:0) and tetracosanoic acid (C24:0) in different tissues and in biological fluids. The disease is clinically characterized by central and peripheral demyelination and adrenal insufficiency, which is closely related to the increased concentrations of these fatty acids. However, the mechanisms underlying the brain damage in X-ALD are poorly known. Considering that free radical generation is involved in various neurodegenerative disorders, like Parkinson disease, multiple sclerosis and Alzheimer's disease, in the present study we evaluated various oxidative stress parameters, namely chemiluminescence, thiobarbituric acid reactive species (TBA-RS), total radical-trapping antioxidant potential (TRAP), and total antioxidant reactivity (TAR) in plasma of X-ALD patients, as well as the activities of the antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) in erythrocytes and fibroblasts from these patients. It was verified a significant increase of plasma chemiluminescence and TBA-RS, reflecting induction of lipid peroxidation, as well as a decrease of plasma TAR, indicating a deficient capacity to rapidly handle an increase of reactive species. We also observed a significant increase of erythrocytes GPx activity and of catalase and SOD activities in fibroblasts from the patients studied. It is therefore proposed that oxidative stress may be involved in pathophysiology of X-ALD.

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