Effect of sources and levels of selenium on physiological traits in broilers

We evaluated the apparent retention, the hepatic, tissue and plasmatic deposition as well as the efficiency of the enzyme hepatic and plasmatic Glutathione Peroxidase in broiler chickens fed different sources and levels of selenium. 300 male Cobb- 500 chicks aged 14 days were submitted to a factorial scheme 3x3+1 (three levels - 0.150; 0.300; 0.450ppm, three commercial sources - one inorganic and two organic + one control treatment without a supplementation) in CRD. The first 14 days of age (depletion period) the birds were fed basal diets without a supplementation of selenium. At 14 days the birds were given the diets with selenium for a period for 14 days, and the excreta collected in the last four days. The work suggested that the selenium retentions were relatively high, due to the use of organic source A at growing levels they presented a lower decrease in apparent retention of selenium. The organic sources participated more actively in the activities of tissues in general and the inorganic source is neutralized in the hepatic tissue. The efficiency of this enzyme in plasma was increased linearly, when we increased dietary levels for the inorganic source there was no change in efficiency.Avaliaram-se a retenção aparente, a deposição hepática, tecidual e plasmática, bem como a eficiência da glutationa peroxidase hepática e plasmática em frangos de corte alimentados com diferentes níveis e fontes de selênio. Utilizaram-se 300 pintos machos com 14 dias, submetidos a um esquema fatorial 3x3 + 1 (três níveis de Se - 0,150; 0,300; 0,450ppm, e três fontes comerciais de Se - uma inorgânica e duas orgânicas + um tratamento controle sem suplementação), em DIC. Do primeiro ao 14º dia de idade - período de depleção -, as aves receberam rações basais sem suplementação de selênio. Aos 14 dias, receberam as dietas com selênio, por um período de 14 dias, sendo coletadas as excretas nos últimos quatro dias. A retenção de selênio foi relativamente alta. O uso da fonte orgânica A em níveis crescentes apresentou menor queda na retenção aparente de selênio. As fontes orgânicas participaram mais ativamente nas atividades de tecidos de forma geral, e a fonte inorgânica foi neutralizada no tecido hepático. A eficiência dessa enzima no plasma aumentou linearmente quando se elevaram os níveis dietéticos. Para a fonte inorgânica, não houve mudança nesta eficiência

Miastenia grave: avaliação clinica e terapêutica de 55 casos

Foram estudados 55 casos de miastenia grave, avaliando os sinais e sintomas clínicos que ocorreram no início e na evolução dos pacientes, bem como os procedimentos diagnósticos e avaliação das medidas terapêuticas utilizadas. No manejo dos pacientes foram utilizados anticolinesterásicos, corticoesteróides, azathioprina, plasmaferese e timectomia, sem que fosse possível encontrar relação estatística significante entre os diferentes procedimentos com respeito à resolução da doença. Dos 55 casos, 9 (16,6%) obtiveram remissão total, 41 (74,5%) permaneceram com a doença ativa necessitando de tratamento sintomático e 5 (9.09%) faleceram. Houve relação estatística significante entre os sinais de insuficiência respiratória, crises miastênicas e timoma somente no grupo de pacientes que faleceram (um por insuficiência respiratória restritiva secundária a cifoescoliose severa, três com timoma e um caso durante a timectomia)

Fine roots stimulate nutrient release during early stages of leaf litter decomposition in a Central Amazon rainforest

Purpose Large parts of the Amazon rainforest grow on weathered soils depleted in phosphorus and rock-derived cations. We tested the hypothesis that in this ecosystem, fine roots stimulate decomposition and nutrient release from leaf litter biochemically by releasing enzymes, and by exuding labile carbon stimulating microbial decomposers. Methods We monitored leaf litter decomposition in a Central Amazon tropical rainforest, where fine roots were either present or excluded, over 188 days and added labile carbon substrates (glucose and citric acid) in a fully factorial design. We tracked litter mass loss, remaining carbon, nitrogen, phosphorus and cation concentrations, extracellular enzyme activity and microbial carbon and nutrient concentrations. Results Fine root presence did not affect litter mass loss but significantly increased the loss of phosphorus and cations from leaf litter. In the presence of fine roots, acid phosphatase activity was 43.2% higher, while neither microbial stoichiometry, nor extracellular enzyme activities targeting carbon- and nitrogen-containing compounds changed. Glucose additions increased phosphorus loss from litter when fine roots were present, and enhanced phosphatase activity in root exclusions. Citric acid additions reduced litter mass loss, microbial biomass nitrogen and phosphorus, regardless of fine root presence or exclusion. Conclusions We conclude that plant roots release significant amounts of acid phosphatases into the litter layer and mobilize phosphorus without affecting litter mass loss. Our results further indicate that added labile carbon inputs (i.e. glucose) can stimulate acid phosphatase production by microbial decomposers, highlighting the potential importance of plant-microbial feedbacks in tropical forest ecosystems