BackgroundExercise training (T) blunts functional deficits and renin-angiotensin system (RAS) hyperactivity in hypertensive individuals. There is no information on T-induced temporal changes of brain RAS. We evaluate now the simultaneous effects of T on functional responses and time course changes in the expression/activity of brain RAS components in autonomic cardiovascular-controlling areas.Methods and ResultsSpontaneously hypertensive rats (SHR) and age-matched normotensive controls (WKY) were trained for 0, 1, 2, 4, 8 and 12 weeks. Sedentary (S) groups served as time-controls. After arterial pressure (AP) and heart rate (HR) recordings at rest, fresh and fixed brains were harvested for qPCR and immunofluorescence assays. SHR-S vs. WKY-S exhibited higher mean AP (MAP) and HR, increased pressure variability and sympathetic activity, elevated AT1 receptor (AT1) expression in nucleus tractus solitarii (NTS) and higher Mas receptor expression in the rostroventrolateral medulla (RVLM). In SHR, T promptly (T2 on) reduced sympathetic variability to heart/vessels and largely decreased angiotensinogen expression in the paraventricular hypothalamic nucleus (PVN) and NTS, with a late RVLM reduction (T4). AT1 expression was only reduced at T12 (PVN and NTS) with transient, not maintained Mas receptor changes in PVN and RVLM. These responses were accompanied by baseline MAP and HR reduction in the SHR-T (from T4 on). In the SHR group, PVN angiotensinogen expression correlated positively with sympathetic activity, resting MAP and HR. In WKY-T, a precocious (T2-T12) RVLM AT1 decrease preceded the appearance of resting bradycardia (from T8 on).ConclusionsEarly and maintained reduction of angiotensinogen content in autonomic areas of the SHR is the most prominent effect of training on brain RAS. Down-regulation of PVN RAS expression is an essential factor to drive cardiovascular benefits in SHR-T, while resting bradycardia in WKY-T is correlated to RVLM AT1 reduction.

The production of beef cattle in the Atlantic Forest biome mostly takes place in pastoral production systems. There are millions of hectares covered with pastures in this biome, including degraded pasture (DP), and only small area of the original Atlantic Forest has been preserved in tropics, implying that actions must be taken by the livestock sector to improve sustainability. Intensification makes it possible to produce the same amount, or more beef, in a smaller area; however, the environmental impacts must be assessed. Regarding climate change, the C dynamics is essential to define which beef cattle systems are sustainable. The objectives of this study were to investigate the C balance (t CO2e./ha per year), the intensity of C emission (kg CO2e./kg BW or carcass) and the C footprint (t CO2e./ha per year) of pasture-based beef cattle production systems, inside the farm gate and considering the inputs. The results were used to calculate the number of trees to be planted in beef cattle production systems to mitigate greenhouse gas (GHG) emissions. The GHG emission and C balance, for 2 years, were calculated based on the global warming potential (GWP) of AR4 and GWP of AR5. Forty-eight steers were allotted to four grazing systems: DP, irrigated high stocking rate pasture (IHS), rainfed high stocking rate pasture (RHS) and rainfed medium stocking rate pasture (RMS). The rainfed systems (RHS and RMS) presented the lowest C footprints (−1.22 and 0.45 t CO2e./ha per year, respectively), with C credits to RMS when using the GWP of AR4. The IHS system showed less favorable results for C footprint (−15.71 t CO2e./ha per year), but results were better when emissions were expressed in relation to the annual BW gain (−10.21 kg CO2e./kg BW) because of its higher yield. Although the DP system had an intermediate result for C footprint (−6.23 t CO2e./ha per year), the result was the worst (−30.21 CO2e./kg BW) when the index was expressed in relation to the annual BW gain, because in addition to GHG emissions from the animals in the system there were also losses in the annual rate of C sequestration. Notably, the intensification in pasture management had a land-saving effect (3.63 ha for IHS, 1.90 for RHS and 1.19 for RMS), contributing to the preservation of the tropical forest.

* Bolsista Produtividade do CNPq.RESUMO -O objetivo neste estudo foi avaliar os efeitos de dietas com diferentes níveis de bagaço de laranja em substituição à silagem de sorgo sobre o comportamento ingestivo de ovinos (alimentação, ruminação e ócio) em ovinos. Dezesseis ovinos machos mestiços, com peso médio de 28,27 kg (±2,41) foram distribuídos em delineamento experimental em blocos casualizados com quatro tratamentos (0, 25, 50 e 75%), dois blocos e duas repetições por bloco. Os animais foram submetidos à observação visual durante dois dias consecutivos. No primeiro dia, os animais foram avaliados durante três períodos (8 às 10 h, 14 às 16 h e 18 às 20 h), estimando-se a média do número de mastigações merícicas por bolo ruminal e a média do tempo despendido de mastigação merícica por bolo ruminal, utilizando-se cronômetro digital. No segundo dia, o comportamento ingestivo de cada ovino foi determinado visualmente, a intervalos de cinco minutos, durante 24 horas, para determinação do tempo despendido em ócio, alimentação e ruminação. Não houve diferença entre os tratamentos, para o tempo despendido em alimentação, em min/dia e min/kg de MS e FDN. Os tempos despendidos em ruminação e ócio apresentaram efeitos quadráticos em função da inclusão de bagaço de laranja nas dietas. O tempo de ruminação em min/kg de MS apresentou efeito linear decrescente, logo, o tempo de ruminação em min/kg FDN não apresentou diferença significativa. Não se observou diferença para o número de refeições/dia, o tempo de mastigação total, os números de bolos ruminais, o número de mastigações por bolo e o tempo de mastigação por bolo. Os números de períodos ruminais e de mastigações merícicas por dia apresentaram comportamento linear decrescente. Palavras-chave: alimentação, ócio, ruminaçãoIngestive behaviour of sheep fed with different levels of fresh orange pulp replacing sorghum silage in the diet ABSTRACT -The objective of this study was to evaluate the effects of diets with different levels of fresh orange pulp in substitution to sorghum silage on eating behavior (feeding, rumination and idle)in sheep. Sixteen wethers, crossbred breeds averaging 28.27 kg BW (±2.41) were allotted to a randomized blocks design, with four treatments (0, 25, 50, and 75%), two blocks and two replicates per block. Animals were evaluated by observation during two consecutive days. In the first day, the average number of chewing per ruminal bolus and the average time spending in the chewing per ruminal bolus were evaluated during three periods (8 to 10 hours, 14 to 16 hours and 18 to 20 hours). In the second day, the behaviour was visually determined during 24 hours with five minutes intervals to determine the times spent in idle, feeding, rumination. There was not difference for the time spent with feeding in minutes day and in minutes/kg of DM and NDF. The time spent in rumination and idle in minutes day showed a quadratic effect in function of increased levels of fresh citrus pulp in the diets. The time spent in rumination, in minutes for kg MS, presente...

SUMMARY de amônia, 15 N,

Changes in lifestyle such as increase in high-fat food consumption are an important cause for vascular diseases. The present study aimed to investigate the involvement of ACE and TGF-β in the aorta stiffness induced by high-fat diet. C57BL/6 male mice were divided in two groups according to their diet for 8 weeks: standard diet (ST) and high-fat diet (HF). At the end of the protocol, body weight gain, adipose tissue content, serum lipids and glucose levels, and aorta morphometric and biochemical measurements were performed. Analysis of collagen fibers by picrosirius staining of aorta slices showed that HF diet promoted increase of thin (55%) and thick (100%) collagen fibers deposition and concomitant disorganization of these fibers orientations in the aorta vascular wall (50%). To unravel the mechanism involved, myeloperoxidase (MPO) and angiotensin I converting enzyme (ACE) were evaluated by protein expression and enzyme activity. HF diet increased MPO (90%) and ACE (28%) activities, as well as protein expression of ACE. TGF-β was also increased in aorta tissue of HF diet mice after 8 weeks. Altogether, we have observed that the HF diet-induced aortic stiffening may be associated with increased oxidative stress damage and activation of the RAS in vascular tissue.

No abstract

Increasing greenhouse gas emissions from anthropogenic activities have contributed to global warming and consequently, to climate change. Among all sources of emissions, the agricultural sector accounts for just under a quarter, mainly because of the intensification of food production systems necessary to supply the growing demand of the population. As ruminal fermentation is the largest source of methane emission in the livestock industry, emission by cattle has become the focus of studies. The aim of this study was to evaluate enteric methane emission and emission intensities of Nellore cattle at different ages submitted to levels of intensification of the grazing system. Twenty-four animals per cycle (age of 21.8 and 13.1 months in cycles 1 and 2, respectively) were randomly distributed across different grazing systems: irrigated pasture with a high stocking rate (IHS), dry land pasture with a high stocking rate (DHS), recovering dry land pasture with a moderate stocking rate (DMS), and degraded pasture (DP). Methane emission was measured using the sulfur hexafluoride technique in each season of the cycle. Intensive systems provided higher yields of good-quality forage, as well as superior animal performance when compared to DP. Methane yields were different between seasons and cycles. CH4 emissions per average daily weight gain and dry matter digestible intake were difference between treatments. Differences in the results were observed when they were analyzed per hectare, with the highest gain yield (P = 0.0134), stocking rate, weight gain, carcass production, and total methane emission (P < 0.0001) being found for the intensive systems. There were no differences in emissions per weight gain or carcass production between production systems, while a difference was observed between cycles (P = 0.0189 and P = 0.0255, respectively), resulting in lower emission intensities for younger animals. We conclude that more intensive systems resulted in a higher kg production of carcass per hectare; however, animals at 19 months of age raised in the IHS and DMS systems had a lower emission intensity in kg of CO2-eq. per kg of carcass. Moderate intensification (DMS) using animals at about 19 months of age might be an effective strategy to mitigate GHG emissions from Brazilian tropical pastures. Further studies are needed to understand the relationship between increasing productivity and decreasing environmental impacts, especially methane emission from ruminants.

RESUMOO conhecimento da variabilidade espacial das propriedades do solo é útil para o uso racional dos insumos, como na aplicação localizada de calcário e fertilizantes. O manejo intensivo de pastagens integra várias tecnologias como correção do solo e adubação, irrigação e pastejo rotacionado. O uso de calcário e o fertilizante são fatores-chave para a intensificação do manejo de pastagens, a agricultura de precisão (PA) é a ferramenta para melhorar a eficiência do uso destes insumos. O objetivo deste trabalho foi mapear e avaliar a variabilidade espacial das propriedades do solo após calagem e aplicação de fertilizante fosfatado e o custo de produção de uma pastagem manejada intensivamente. O estudo de campo foi realizado em uma área de 1,7 ha de pastagem de capim Tanzânia irrigado em São Carlos, SP. Na safra seguinte, após a correção do solo com calcário e adubação com fósforo e potássio utilizando a tecnologia da taxa variável de aplicação, amostras de solo foram coletadas a 0-0,2 m de profundidade, e cada amostra representou um piquete. A variabilidade espacial das propriedades do solo e das necessidades específicas de calcário e fertilizantes foram modeladas utilizando-se semivariogramas. A variabilidade espacial das propriedades do solo e a necessidade de calagem e adubação foram modeladas por semi-variogramas, e os dados interpolados. Os resultados mostraram que a tecnologia de aplicação em taxa variável de calcário e superfosfato simples proporcionaram aumentos dos valores do pH, P, Ca, Mg e a V%. A tecnologia da aplicação de insumos à taxa variável pode ser utilizada como ferramenta de correção e adubação do solo levando à maior homogeneidade dos atributos químicos do solo, e também na redução do custo de produção. Palavras-chave:Megathyrsus maximus, capim Tanzânia, fertilidade do solo, taxa variável. ABSTRACTKnowledge on spatial variability of soil properties is useful for the rational use of inputs, as in the site-specific application of lime and fertilizer. Intensive pasture management integrates * alberto.bernardi@embrapa.br