RESUMO
Objetivou-se avaliar a qualidade de silagens de milheto, confeccionadas com o uso de aditivos, por meio da avaliação de pH, composição química e digestibilidade in vitro da matéria seca (DIVMS). Os tratamentos consistiram em milheto: com ou sem grãos de sorgo e com ou sem inoculante, em esquema fatorial (2x2). Teores de matéria seca (MS), proteína bruta (PB) e DIVMS aumentaram com a inclusão de sorgo. O pH das silagens com sorgo e inoculadas foi menor que o das silagens de milheto controle. O teor de nitrogênio insolúvel em detergente ácido (NIDA) e de fibra em detergente ácido (FDA) foi menor para a silagem com sorgo. A inoculação não influenciou a MS (23,76%) e DIVMS (48,90%). Houve interação entre inclusão de sorgo e inoculante para fibra em detergente neutro (FDN). A adição de grão de sorgo melhora as características da silagem, resultado de melhor conservação. O uso de inoculante reduz o pH, inibindo fermentações indesejáveis e proporcionando maiores teores de PB...
The objective of this study was to evaluate the quality of millet silage produced with additives by evaluating pH, chemical composition and in vitro dry matter digestibility (IVDMD). The treatments consisted of millet with or without sorghum grains and with or without microbial inoculant in a factorial scheme (2x2). Dry matter content, crude protein content and IVDMD increased with sorghum inclusion. The pH of silage containing sorghum and microbial inoculant was lower than that of control millet silage. Acid detergent insoluble nitrogen and acid detergent fiber content were lower in silage containing sorghum. Microbial inoculation did not influence dry matter (23.76%) or IVDMD (48.9%). There was an interaction between sorghum inclusion and microbial inoculant for neutral detergent fiber. The addition of sorghum grain and microbial inoculant improves silage characteristics as a result of better preservation. The use of microbial inoculant reduces pH, inhibiting undesirable fermentation and increasing crude protein content...
Assuntos
Animais , Fermentação , Ração Animal , Silagem , Lactobacillus plantarum , Pediococcus , Sorghum/químicaRESUMO
Objetivou-se avaliar a qualidade de silagens de milheto, confeccionadas com o uso de aditivos, por meio da avaliação de pH, composição química e digestibilidade in vitro da matéria seca (DIVMS). Os tratamentos consistiram em milheto: com ou sem grãos de sorgo e com ou sem inoculante, em esquema fatorial (2x2). Teores de matéria seca (MS), proteína bruta (PB) e DIVMS aumentaram com a inclusão de sorgo. O pH das silagens com sorgo e inoculadas foi menor que o das silagens de milheto controle. O teor de nitrogênio insolúvel em detergente ácido (NIDA) e de fibra em detergente ácido (FDA) foi menor para a silagem com sorgo. A inoculação não influenciou a MS (23,76%) e DIVMS (48,90%). Houve interação entre inclusão de sorgo e inoculante para fibra em detergente neutro (FDN). A adição de grão de sorgo melhora as características da silagem, resultado de melhor conservação. O uso de inoculante reduz o pH, inibindo fermentações indesejáveis e proporcionando maiores teores de PB...(AU)
The objective of this study was to evaluate the quality of millet silage produced with additives by evaluating pH, chemical composition and in vitro dry matter digestibility (IVDMD). The treatments consisted of millet with or without sorghum grains and with or without microbial inoculant in a factorial scheme (2x2). Dry matter content, crude protein content and IVDMD increased with sorghum inclusion. The pH of silage containing sorghum and microbial inoculant was lower than that of control millet silage. Acid detergent insoluble nitrogen and acid detergent fiber content were lower in silage containing sorghum. Microbial inoculation did not influence dry matter (23.76%) or IVDMD (48.9%). There was an interaction between sorghum inclusion and microbial inoculant for neutral detergent fiber. The addition of sorghum grain and microbial inoculant improves silage characteristics as a result of better preservation. The use of microbial inoculant reduces pH, inhibiting undesirable fermentation and increasing crude protein content...(AU)
Assuntos
Animais , Silagem , Fermentação , Ração Animal , Sorghum/química , Lactobacillus plantarum , PediococcusRESUMO
Mitochondrial beta-ketothiolase and 2-methyl-3-hydroxybutyryl-CoA dehydrogenase (MHBD) deficiencies are inherited neurometabolic disorders affecting isoleucine catabolism. Biochemically, beta-ketothiolase deficiency is characterized by intermittent ketoacidosis and urinary excretion of 2-methyl-acetoacetate (MAA), 2-methyl-3-hydroxybutyrate (MHB) and tiglylglycine (TG), whereas in MHBD deficiency only MHB and tiglylglycine accumulate. Lactic acid accumulation and excretion are also observed in these patients, being more pronounced in MHBD-deficient individuals, particularly during acute episodes of decompensation. Patients affected by MHBD deficiency usually manifest severe mental retardation and convulsions, whereas beta-ketothiolase-deficient patients present encephalopathic crises characterized by metabolic acidosis, vomiting and coma. Considering that the pathophysiological mechanisms responsible for the neurological alterations of these disorders are unknown and that lactic acidosis suggests an impairment of energy production, the objective of the present work was to investigate the in vitro effect of MAA and MHB, at concentrations varying from 0.01 to 1.0 mmol/L, on several parameters of energy metabolism in cerebral cortex from young rats. We observed that MAA markedly inhibited CO2 production from glucose, acetate and citrate at concentrations as low as 0.01 mmol/L. In addition, the activities of the respiratory chain complex II and succinate dehydrogenase were mildly inhibited by MAA. MHB, at 0.01 mmol/L and higher concentrations, strongly inhibited CO2 production from all tested substrates, as well as the respiratory chain complex IV activity. The other activities of the respiratory chain were not affected by these metabolites. The data indicate a marked blockage in the Krebs cycle and a mild inhibition of the respiratory chain caused by MAA and MHB. Furthermore, MHB inhibited total and mitochondrial creatine kinase activities, which was prevented by the use of the nitric-oxide synthase inhibitor L-NAME and glutathione (GSH). These data indicate that the effect of MHB on creatine kinase was probably mediated by oxidation or other modification of essential thiol groups of the enzyme by nitric oxide and other by-products derived from this organic acid. In contrast, MAA did not affect creatine kinase activity. Taken together, these observations indicate that aerobic energy metabolism is inhibited by MAA and to a greater extent by MHB, a fact that may be related to lactic acidaemia occurring in patients affected by MHBD and beta-ketothiolase deficiencies. If the in vitro effects detected in the present study also occur in vivo, it is tempting to speculate that they may contribute, at least in part, to the neurological dysfunction found in these disorders.
Assuntos
Acetoacetatos/farmacologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/embriologia , Metabolismo Energético , Hidroxibutiratos/farmacologia , 3-Hidroxiacil-CoA Desidrogenases , Acetatos/metabolismo , Acetil-CoA C-Aciltransferase/metabolismo , Acidose/metabolismo , Oxirredutases do Álcool/metabolismo , Animais , Encéfalo/metabolismo , Dióxido de Carbono/química , Dióxido de Carbono/metabolismo , Córtex Cerebral/metabolismo , Citratos/metabolismo , Creatina Quinase/metabolismo , Relação Dose-Resposta a Droga , Transporte de Elétrons , Glucose/metabolismo , Glutationa/metabolismo , Glicina/análogos & derivados , Glicina/metabolismo , Técnicas In Vitro , Deficiência Intelectual , Ácido Láctico/metabolismo , NG-Nitroarginina Metil Éster/metabolismo , NG-Nitroarginina Metil Éster/farmacologia , Oxigênio/metabolismo , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Accumulation of methylmalonic acid (MMA) in tissues and biological fluids is the biochemical hallmark of patients affected by the neurometabolic disorder known as methylmalonic acidemia (MMAemia). Although this disease is predominantly characterized by severe neurological findings, the underlying mechanisms of brain injury are not totally established. In the present study, we investigated the effect of MMA, as well as propionic (PA) and tiglic (TA) acids, whose concentrations are also increased but to a lesser extend in MMAemia, on total (tCK), cytosolic (Cy-CK) and mitochondrial (Mi-CK) creatine kinase (CK) activities from cerebral cortex of 30-day-old Wistar rats. Total CK activity (tCK) was measured in whole cell homogenates, whereas Cy-CK and Mi-CK were determined, respectively, in cytosolic and mitochondrial preparations from rat cerebral cortex. We verified that tCK and Mi-CK activities were significantly inhibited by MMA at concentrations as low as 1 mM, in contrast to Cy-CK which was not affected by the presence of the acid in the incubation medium. Furthermore, PA and TA, at concentrations as high as 5 mM, did not alter CK activity. We also observed that the inhibitions provoked by MMA were fully prevented by pre-incubation of the homogenates with reduced glutathione, suggesting that the inhibitory effect of MMA was possibly mediated by oxidation of essential thiol groups of the enzyme. Considering the importance of CK for brain metabolism homeostasis, our results suggest that inhibition of this enzyme by increased levels of MMA may contribute to the neurodegeneration of patients affected by MMAemia and explain previous reports showing an impairment of brain energy metabolism and a reduction of brain phosphocreatine levels caused by MMA.
Assuntos
Córtex Cerebral/enzimologia , Creatina Quinase/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Ácido Metilmalônico/farmacologia , Mitocôndrias/enzimologia , Animais , Antioxidantes/farmacologia , Córtex Cerebral/efeitos dos fármacos , Crotonatos/farmacologia , Citosol/efeitos dos fármacos , Citosol/metabolismo , Metabolismo Energético/efeitos dos fármacos , Metabolismo Energético/fisiologia , Hemiterpenos , Técnicas In Vitro , Indicadores e Reagentes , Masculino , Mitocôndrias/efeitos dos fármacos , Proteínas do Tecido Nervoso/metabolismo , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase Tipo I , Propionatos/farmacologia , RatosRESUMO
A predominantly neurological presentation is common in patients with glutaric acidemia type I (GA-I). 3-hydroxyglutaric acid (3-OHGA), which accumulates in affected patients, has recently been demonstrated to play a central role in the neuropathogenesis of this disease. In the present study, we investigated the in vitro effects of 3-OHGA at concentrations ranging from 10 to 1000 microM on various parameters of the glutamatergic system, such as the basal and potassium-induced release of [3H]glutamate by synaptosomes, as well as on Na+-dependent [3H]glutamate uptake by synaptosomes and astrocytes and Na+-independent [3H]glutamate uptake by synaptic vesicles from cerebral cortex of 30-day-old Wistar rats. First, we observed that exposure of cultured astrocytes to 3-OHGA for 20 h did not reduce their viability. Furthermore, 3-OHGA significantly increased Na+-dependent [3H]glutamate uptake by astrocytes by up to 80% in a dose-dependent manner at doses as low as 30 microM. This effect was not dependent on the presence of the metabolite during the uptake assay, since it occurred even when 3-OHGA was withdrawn from the medium after cultured cells had been exposed to the acid for approximately 1 h. All other parameters investigated were not influenced by this organic acid, indicating a selective action of 3-OHGA on astrocyte transporters. Although the exact mechanisms involved in 3-OHGA-stimulatory effect on astrocyte glutamate uptake are unknown, the present findings contribute to the understanding of the pathophysiology of GA-I, suggesting that astrocytes may protect neurons against excitotoxic damage caused by 3-OHGA by increasing glutamate uptake and therefore reducing the concentration of this excitatory neurotransmitter in the synaptic cleft.
Assuntos
Astrócitos/metabolismo , Córtex Cerebral/metabolismo , Ácido Glutâmico/metabolismo , Glutaratos/farmacologia , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Córtex Cerebral/citologia , Córtex Cerebral/efeitos dos fármacos , Masculino , Proteínas do Tecido Nervoso/biossíntese , Ratos , Ratos Wistar , Estimulação Química , Vesículas Sinápticas/efeitos dos fármacos , Vesículas Sinápticas/metabolismo , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismoRESUMO
The aim of this study was to know the nurses' conception about the emphasis of the activities that they develop in the work process, in the clinic model assistance. This study is a qualitative research, with dialetic approach. To form the sample one nurse was chosen in each of the 17 units of a university hospital in Porto Alegre/RS. The data were collected through semi-structured interview. To analyze the data the material was classified in relevant structures, from which nine categories were established. The results showed that, although there is a prevalence of management activities of the care concerning the assistance activities, the nurses considered that these dimensions are indissociable in their work. It was concluded that the relation between assisting and managing are not excluding and that the management is one of the dimensions of nursing care.