Soil properties under Amazon forest and changes due to pasture installation in Rondônia, Brazil

We examined the consequences of deforestation and pasture establishment for soil chemical and physical properties and for soil organic matter content, in Rondônia, in the southwestern part of the Brazilian Amazon basin. Two chronosequences, were selected. One chronosequence consisted of a forest and pasture established in 1989, 1987, 1983, 1979 and 1972. The main soil type in this area is the red yellow podzolic latosol (Kandiudult). The second chronosequence consisted of a forest site and pasture established in 1987, 1983, 1972 and 1911, and the main soil type is a red yellow podzolic soil (Paleudult, Tropudult). The first soil type is the most base-depleted soil and has a higher clay content than the second one. Despite the initial differences in clay and cations contents between the forest sites the total soil carbon content at 0-30 cm in both forest were circa 3.7 kg C/m2. After pasture installation soil bulk density were higher in the first 0-5 cm soil layer, mainly in one chronosequence but small changes were detected in deeper soil layers. Forest conversion to pasture caused appreciable increases in soil pH and exchangeable cation content, at least until nine years after pasture installation. pH levels were greater in the first chronosequence, with highest values (6.8 to 7.6) found in 3 and 5 years old pastures respectively. In the most base-depleted soil Ca content increased from 0.07 kg/m2 in the forest sites to 0.25 kg/m2 in the 5 year old pasture. After normalization by clay content total soil carbon contents to 30 cm in the 20 year old pastures were 17 to 20% higher than in the original forest sites. Calculations of carbon derived from forest (Cdf) and from pasture (Cdp) using soil delta 13C values showed that Cdf decrease sharply in the first 9 years after pasture establishment in both chronosequences and reached stable values of 2.12 kg C/m2 and 2.02 kg C/m2 in sequences 1 and 2, respectively... (D'après résumé d'auteur

Alternatives to the use of antibiotics for laying hens in growing phase

This study evaluated the performance, immune response to vaccination, digestive organs, intestinal histomorphometry, and microbiological development in the diet and litter of Isa Brown strains at growing receiving phase alternative additives in the place of antibiotics. Four treatments were arrayed in a completely randomized design: T1) Basal diet without antibiotics, T2) Basal diet with antibiotics, T3) Basal diet with probiotics, and T4) Basal diet without antibiotics and water modified by a photoelectron generator. There were six replications of eight birds each and thus a total of 192 birds. Performance was evaluated for eight weeks and during this period blood samples were collected at 9, 12 and 15 weeks of age for serological evaluation. At the end of the experimental period, 24 birds were euthanized, collecting the intestinal tract and later performing histomorphometry. Microbiological analyses were performed in the experimental diets and in the material of the litter of the boxes. The results obtained were analyzed by analysis of variance and the contrast between treatment means when significant by Tukey’s test. The results indicate that the replacement of antibiotics with T3 or T4 did not interfere negatively (P >0.05) in the performance of the birds, immunological response, viscera analyses and intestinal histomorphometry. In addition, use of T3 and T4 might lead to more rapid decomposition of excreta and reduce antibiotic residue in the soil when the litter is used in crop production.Keywords: dileka, Gallus domesticus, histomorphometry, laying hens, probiotics, serum biochemistry, wate

Assessment of rubber tree panels under crowns resistant to South American leaf blight

The objective of this work was to assess the performance of panel clones under crowns resistant to South American leaf blight (Microcyclus ulei). The experiment was carried out with 18 panel clones crown-budded with Hevea pauciflora x H. guianensis, in a Xanthic Ferralsol (Oxisol) in Manaus, AM, Brazil. The following parameters were evaluated: dry rubber yield, plant nutritional status, and anatomical and physiological characteristics of the latex vessels. In the first three years of evaluation, the panel clones IAN 2878, IAN 2903, CNS AM 7905, CNS AM 7905 P1, and PB 28/59 showed the highest dry rubber yield potential, while the clones IAN 6158, IAN 6590, and IAN 6515 should not be recommended for crown budding. Higher potassium and copper foliar content in panel clones were associated to an increase in dry rubber yield. The simultaneous evaluation of anatomical and physiological characteristics of latex is fundamental for the selection of panel clones in the Amazon region. Crown budding is an efficient technology for South American leaf blight management in endemic regions

Altered glucose homeostasis and hepatic function in obese mice deficient for both kinin receptor genes

The Kallikrein-Kinin System (KKS) has been implicated in several aspects of metabolism, including the regulation of glucose homeostasis and adiposity. Kinins and des-Arg-kinins are the major effectors of this system and promote their effects by binding to two different receptors, the kinin B2 and B1 receptors, respectively. To understand the influence of the KKS on the pathophysiology of obesity and type 2 diabetes (T2DM), we generated an animal model deficient for both kinin receptor genes and leptin (obB1B2KO). Six-month-old obB1B2KO mice showed increased blood glucose levels. Isolated islets of the transgenic animals were more responsive to glucose stimulation releasing greater amounts of insulin, mainly in 3-month-old mice, which was corroborated by elevated serum C-peptide concentrations. Furthermore, they presented hepatomegaly, pronounced steatosis, and increased levels of circulating transaminases. This mouse also demonstrated exacerbated gluconeogenesis during the pyruvate challenge test. The hepatic abnormalities were accompanied by changes in the gene expression of factors linked to glucose and lipid metabolisms in the liver. Thus, we conclude that kinin receptors are important for modulation of insulin secretion and for the preservation of normal glucose levels and hepatic functions in obese mice, suggesting a protective role of the KKS regarding complications associated with obesity and T2DM

ANÁLISE EXPLORATÓRIA DOS POTENCIAIS EFEITOS DAS MUDANÇAS CLIMÁTICAS NOS "VALES DA UVA GOETHE"

The future of agriculture has been conditioned by uncertainties about the effects of climate change. Thus, the main goal of this work is to develop an exploratory analysis of the potential impacts of climate change in dynamics in the vitiviniculture in the region bounded by the Indication of Origin of Vales da Uva Goethe. The analysis was developed based on direct consultation at producers and production and climate data. The results indicate that only share of producers has related changes in the quantity and quality of the grapes to the effects of climate change. However, there was an actual change in climate. The average monthly minimum temperatures increased from 5.75°C to 8.30°C 1924-2012, which can increase the probability of occurrence of disease and pests associated with high average temperatures.O futuro da agricultura está condicionado as incertezas envolvidas em relação aos efeitos das mudanças climáticas. Deste modo, o objetivo principal deste trabalho é desenvolver uma análise exploratória a respeito dos potenciais impactos decorrentes da mudança na dinâmica climática na vitivinicultura na região delimitada pela Indicação de Procedência dos Vales da Uva Goethe. A análise foi desenvolvida com base em consulta direta aos produtores e dados climáticos e da produção da região. Os resultados indicam que apenas parcela dos produtores relaciona as variações na quantidade e na qualidade das uvas aos efeitos das mudanças climáticas. Todavia, constatou-se uma efetiva alteração no clima. As temperaturas médias mínimas mensais aumentaram de 5,75° C para 8,30° C entre 1924 a 2012, o que pode elevar a probabilidade de ocorrência de doenças e pragas associadas às altas temperaturas médias.El futuro de la agricultura está condicionado las incertidumbres sobre los efectos del cambio climático. Por lo tanto, el objetivo principal de este trabajo es desarrollar un análisis exploratorio de los impactos potenciales del cambio climático en la dinámica de la viticultura en la región limitada por la Indicación del Origen de Vales da Uva Goethe. El análisis se desarrolló con base en la consulta directa con los productores y de los datos de la producción y climáticos. Los resultados indican que sólo una parte de los productores en relación con los cambios en la cantidad y calidad de la uva a los efectos del cambio climático. Sin embargo, hubo un cambio real en el clima. Las temperaturas mínimas promedio mensual aumentó de 5,75°C para 8,30°C entre 1924-2012, lo que puede aumentar la probabilidad de ocurrencia de enfermedades y plagas asociado con altas temperaturas medias