ENSO and NAO affect long-term leaf litter dynamics and stoichiometry of Scots pine and European beech mixedwoods.

Litterfall dynamics (production, seasonality and nutrient composition) are key factors influencing nutrient cycling. Leaf litter characteristics are modified by species composition, site conditions and water availability. However, significant evidence on how large-scale, global circulation patterns affect ecophysiological processes at tree and ecosystem level remains scarce due to the difficulty in separating the combined influence of different factors on local climate and tree phenology. To fill this gap, we studied links between leaf litter dynamics with climate and other forest processes, such as tree-ring width (TRW) and intrinsic water-use efficiency (iWUE) in two mixtures of Scots pine (Pinus sylvestris L.) and European beech (Fagus sylvatica L.) in the south-western Pyrenees. Temporal series (18 years) of litterfall production and elemental chemical composition were decomposed following the ensemble empirical mode decomposition method and relationships with local climate, large-scale climatic indices, TRW and Scots pine's iWUE were assessed. Temporal trends in N:P ratios indicated increasing P limitation of soil microbes, thus affecting nutrient availability, as the ecological succession from a pine-dominated to a beech-dominated forest took place. A significant influence of large-scale patterns on tree-level ecophysiology was explained through the impact of the North Atlantic Oscillation (NAO) and El Niño-Southern Oscillation (ENSO) on water availability. Positive NAO and negative ENSO were related to dry conditions and, consequently, to early needle shedding and increased N:P ratio of both species. Autumn storm activity appears to be related to premature leaf abscission of European beech. Significant cascading effects from large-scale patterns on local weather influenced pine TRW and iWUE. These variables also responded to leaf stoichiometry fallen 3 years prior to tree-ring formation. Our results provide evidence of the cascading effect that variability in global climate circulation patterns can have on ecophysiological processes and stand dynamics in mixed forests.

Multimodel simulations of forest harvesting effects on long­term productivity and CN cycling in aspen forests.

The effects of forest management on soil carbon (C) and nitrogen (N) dynamics vary by harvest type and species. We simulated long-term effects of bole-only harvesting of aspen (Populus tremuloides) on stand productivity and interaction of CN cycles with a multiple model approach. Five models, Biome-BGC, CENTURY, FORECAST, LANDIS-II with Century-based soil dynamics, and PnET-CN, were run for 350 yr with seven harvesting events on nutrient-poor, sandy soils representing northwestern Wisconsin, United States. Twenty CN state and flux variables were summarized from the models' outputs and statistically analyzed using ordination and variance analysis methods. The multiple models' averages suggest that bole-only harvest would not significantly affect long-term site productivity of aspen, though declines in soil organic matter and soil N were significant. Along with direct N removal by harvesting, extensive leaching after harvesting before canopy closure was another major cause of N depletion. These five models were notably different in output values of the 20 variables examined, although there were some similarities for certain variables. PnET-CN produced unique results for every variable, and CENTURY showed fewer outliers and similar temporal patterns to the mean of all models. In general, we demonstrated that when there are no site-specific data for fine-scale calibration and evaluation of a single model, the multiple model approach may be a more robust approach for long-term simulations. In addition, multimodeling may also improve the calibration and evaluation of an individual model.

PAR-2-mediated control of barrier function and motility differs between early and late phases of postinfectious gut dysfunction in the rat.

Proteinase-activated receptor-2 (PAR-2) and mast cell (MC) mediators contribute to inflammatory and functional gastrointestinal disorders. We aimed to characterize jejunal PAR-2-mediated responses and the potential MC involvement in the early and late phases of a rat model of postinfectious gut dysfunction. Jejunal tissues of control and Trichinella spiralis-infected (14 and 30 days postinfection) rats, treated or not with the MC stabilizer, ketotifen, were used. Histopathology and immunostaining were used to characterize inflammation, PAR-2 expression, and mucosal and connective tissue MCs. Epithelial barrier function (hydroelectrolytic transport and permeability) and motility were assessed in vitro in basal conditions and after PAR-2 activation. Intestinal inflammation on day 14 postinfection (early phase) was significantly resolved by day 30 (late phase) although MC counts and epithelial permeability remained increased. PAR-2-mediated ion transport (Ussing chambers, in vitro) and epithelial surface PAR-2 expression were reduced in the early phase, with a trend toward normalization during the late phase. In control conditions, PAR-2 activation (organ bath) induced biphasic motor responses (relaxation followed by excitation). At 14 days postinfection, spontaneous contractility and PAR-2-mediated relaxations were enhanced; motor responses were normalized on day 30. Postinfectious changes in PAR-2 functions were not affected by ketotifen treatment. We concluded that, in the rat model of Trichinella spiralis infection, alterations of intestinal PAR-2 function and expression depend on the inflammatory phase considered. A lack of a ketotifen effect suggests no interplay between MCs and PAR-2-mediated motility and ion transport alterations. These observations question the role of MC mediators in PAR-2-modulating postinfectious gut dysfunction.

Soil C/N ratios cause opposing effects in forests compared to grasslands on decomposition rates and stabilization factors in southern European ecosystems.

Soils store an important amount of carbon (C), mostly in the form of organic matter in different decomposing stages. Hence, understanding the factors that rule the rates at which decomposed organic matter is incorporated into the soil is paramount to better understand how C stocks will vary under changing atmospheric and land use conditions. We studied the interactions between vegetation cover, climate and soil factors using the Tea Bag Index in 16 different ecosystems (eight forests, eight grasslands) along two contrasting gradients in the Spanish province of Navarre (SW Europe). Such arrangement encompassed a range of four climate types, elevations from 80 to 1420 m.a.s.l., and precipitation (P) from 427 to 1881 mm year-1. After incubating tea bags during the spring of 2017, we identified strong interactions between vegetation cover type, soil C/N and precipitation affecting decomposition rates and stabilization factors. In both forests and grasslands, increasing precipitation increased decomposition rates (k) but also the litter stabilization factor (S). In forests, however, increasing the soil C/N ratio raised decomposition rates and the litter stabilization factor, while in grasslands higher C/N ratios caused the opposite effects. In addition, soil pH and N also affected decomposition rates positively, but for these factors no differences between ecosystem types were found. Our results demonstrate that soil C flows are altered by complex site-dependent and site-independent environmental factors, and that increased ecosystem lignification will significantly change C flows, likely increasing decomposition rates in the short term but also increasing the inhibiting factors that stabilize labile litter compounds.

MADERA: A standardized Pan-Amazonian dataset for tropical timber species.

We compiled and presented a dataset for all timber species reported in the Amazon region from all nine South American Amazonian countries. This was based on official information from every country, as well as from two substantial scientific references. We verified the standard taxonomic names from each individual source, using the Taxonomic Name Resolution Service (TNRS) and considered all Amazonian tree species with diameter at breast height (DBH) ≥10 cm. We also obtained estimates of the current population size for most species from a published approach based on data from 1900 tree inventory plots (1-ha each) distributed across the Amazon region and part from the Amazon Tree Diversity Network (ATDN). We then identified the hyperdominant timber species. In addition, we overlapped our timber species list with data for species that are used for commercial purposes, according to the International Tropical Timber Organization (ITTO), the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the International Union for Conservation of Nature (IUCN) taxa assessment and Red List categories. Finally, we also included IUCN Red List categories based on combined deforestation, and climate change scenarios for these species. Our final Amazonian timber species dataset contains 1112 unique species records, which belong to 337 genera and 72 families from the lowland Amazonian rainforest, with associated information related to population, conservation, and trade status of each species. The authors of this research expect that the information provided will be useful to strengthen the public forestry policies of the Amazon countries, inform ecological studies, as well for forest management purposes. The data are released under the Creative Commons Attribution 4.0 International license.

Thinning affects nutrient resorption and nutrient-use efficiency in two Pinus sylvestris stands in the Pyrenees.

Needle chemical composition was measured, and nutrient resorption, nutrient-use efficiency (NUE), and other indexes were estimated for 24 months in two contrasting natural Pinus sylvestris L. forests in the western Pyrenees in Spain. For each location (Aspurz, 650 m elevation, 7% slope; Garde, 1335 m elevation, 40% slope), there were three reference plots (P0), three plots with 20% of the basal area removed (P20), and three with 30% of the basal area removed (P30). Needle P, Ca, and Mg concentrations were higher in Garde, but N concentration was higher for Aspurz, without differences for K. Nutrient-resorption efficiency of P was higher in Aspurz, of Mg higher in Garde, and there were no differences between sites in N and K. Nutrient-resorption proficiency was significantly higher in the site with lower soil nutrient availability, i.e., for P, Ca, and Mg in Aspurz, but N in Garde (no differences in K); this may be an indicator of nutrient conservation strategy. Annual nutrient productivity (A) was higher for all nutrients in Aspurz, whereas the mean residence time (MRT) was higher in Garde in all nutrients but P. NUE was significantly higher in Garde for all nutrients but P, which was more efficiently used in Aspurz. In both sites, N, P, and K concentrations were higher in the 2002 cohort, Ca in the 2000 cohort, and maximum Mg was found in the 2001 cohort. Thinning caused a reduction of Mg concentration in the 2001 cohort in Aspurz, an increase of Ca resorption proficiency in Aspurz and Mg resorption at both sites, and reduction of P, K, and Mg nutrient response efficiency (NRE) in Garde. Thinning may have caused an increase of the C:Mg ratio through facilitating the development of more biosynthesis apparatus in a more illuminated canopy, but it seemed not to affect resorption in a significant way. Changes in NRE in Garde after thinning show that forest management can affect how trees use nutrients. Our results indicate that the strategy to optimize NUE is different in each stand. In Aspurz (a Mediterranean ecosystem), pine trees carried out resorption more efficiently, while in Garde (a continental forest), trees used nutrients for longer periods of time and reduced their efficiency in using the available soil nutrients after reduced competition by thinning.

Significant increase in ecosystem C can be achieved with sustainable forest management in subtropical plantation forests.

Subtropical planted forests are rapidly expanding. They are traditionally managed for intensive, short-term goals that often lead to long-term yield decline and reduced carbon sequestration capacity. Here we show how it is possible to increase and sustain carbon stored in subtropical forest plantations if management is switched towards more sustainable forestry. We first conducted a literature review to explore possible management factors that contribute to the potentials in ecosystem C in tropical and subtropical plantations. We found that broadleaves plantations have significantly higher ecosystem C than conifer plantations. In addition, ecosystem C increases with plantation age, and reaches a peak with intermediate stand densities of 1500-2500 trees ha⁻¹. We then used the FORECAST model to simulate the regional implications of switching from traditional to sustainable management regimes, using Chinese fir (Cunninghamia lanceolata) plantations in subtropical China as a study case. We randomly simulated 200 traditional short-rotation pure stands and 200 sustainably-managed mixed Chinese fir--Phoebe bournei plantations, for 120 years. Our results showed that mixed, sustainably-managed plantations have on average 67.5% more ecosystem C than traditional pure conifer plantations. If all pure plantations were gradually transformed into mixed plantations during the next 10 years, carbon stocks could rise in 2050 by 260.22 TgC in east-central China. Assuming similar differences for temperate and boreal plantations, if sustainable forestry practices were applied to all new forest plantation types in China, stored carbon could increase by 1,482.80 TgC in 2050. Such an increase would be equivalent to a yearly sequestration rate of 40.08 TgC yr⁻¹, offsetting 1.9% of China's annual emissions in 2010. More importantly, this C increase can be sustained in the long term through the maintenance of higher amounts of soil organic carbon and the production of timber products with longer life spans.

Forests may need centuries to recover their original productivity after continuous intensive management: an example from Douglas-fir stands.

How long would it take for forests to recover their original productivity following continuous intensive management if they are left untouched? This issue was explored using the model FORECAST, calibrated and validated for coastal Douglas-fir stands on Vancouver Island (western Canada). Three types of forest management (production of timber, pulp, and biomass) were simulated, being different in utilization level and rotation length (stem-only and 75-year rotation for timber production, whole-tree and 30-year rotation for pulp/fiber, and whole-tree and 15-year rotations for biomass production). Management was simulated for 150 years, followed by several cycles of natural growth without management ending with a stand-replacing windstorm with a return time of 200 years. Productivity-related ecological variables in previously managed stands were compared to natural forests. Stands developed after management for timber would quickly reach values similar to non-managed forests for tree and understory total biomass, stored carbon, available nitrogen and soil organic matter (SOM). However, intensive management regimes designed for fiber and biomass production would cause a decrease in SOM and nutrient availability, increasing understory biomass. As a consequence, stands recovering from intensive management would need at least two stand-replacing events (400 years) to reach a productivity status similar to non-managed stands. Stands developed after management for biomass would take much longer, up to 600 or 800 years to recover similar values of SOM and understory biomass, respectively. Current fertilization prescriptions will likely be not enough to stop a quick drop in forest productivity associated with intensive management. Intensifying forest management to achieve short-term objectives could produce a reduction of stand productivity that would influence tree growth for very long time (up to several centuries), if such management is continuously implemented at the same stand. Some of these effects could be reduced if one rotation of intensive management (for pulp or bioenergy) is followed by a rotation of management for timber, or by leaving the forest without management for an equivalent time.

Effects of nitrogen deposition on carbon sequestration in Chinese fir forest ecosystems.

Nitrogen deposition and its ecological effects on forest ecosystems have received global attention. We used the ecosystem model FORECAST to assess the effects of nitrogen deposition on carbon sequestration in Chinese fir planted forests in SE China. This topic is important as China is intensifying its reforestation efforts to increase forest carbon sequestration for combating climate change impacts, using Chinese fir as the most important plantation species. A series of scenarios including seven N deposition levels (1, 5, 10, 20, 30, 40 and 50kg ha(-1)y(-1)), three management regime (rotation lengths of 15, 30 and 50 years) and two site qualities (nutrient poor and fertile sites) were defined for the simulations. Our results showed that N deposition increased carbon sequestration in Chinese fir forests, but the efficiency of the increasing effect is reduced as N deposition levels increase. When N deposition levels exceeded 20-30kg ha(-1)y(-1), the incremental effects of N deposition on forest C pools were marginal. This suggests that N deposition levels above 20-30kg ha(-1)y(-1) could lead to N saturation in Chinese fir forest soils. Any additional amounts of N input from deposition would likely be leached out. Total above-ground C was more sensitive to N deposition than to rotation length and site quality. It was also estimated that the contributions of N deposition to C sequestration in all Chinese fir forests in South-East China are 7.4×10(6)MgCy(-1) under the current N deposition levels (5 to 10kg ha(-1)y(-1)) and could reach up to 16×10(6)MgCy(-1) if N deposition continues increasing and reaches levels of 7.5 to 15kg N ha(-1)y(-1).

Primera evidencia experimental de la participación del óxido nítrico en la patología de altura utilizando dos modelos animales / First experimental evidence for the involvement of nitric oxide in the pathology of height using two animal models

La exposición de los organismos a la altura en cambios fisiológicos significantes y puede producir el mal de altura (MA). A pesar de numerosas investigaciones en el último siglo, la fisiopatología del MA todavía no está definida. El objetivo de esta investigación fue determinar los niveles de óxido nítrico (NO) en el plasma de pollos de carne y ratas criados en Huancayo a 3320 msnm comparados con animales de la misma edad criados a nivel del mar. El NO fue determinado indirectamente como nitrito utilizando la reacción de Griess. Nuestros resultados ponen en evidencia la participación del NO en MA en dos modelos animales.

Exposure of the human body to high altitude results in significant physiologic changes and may precipitate mountain sickness (MS). Despite extensive investigations over the last century, the pathophysiology of higt altitude sickness remains elusive. The aim of this research was to examine nitric oxide levels (NO) in plasma from Cobb chickens and rats reared at 3320 meters above sea level in Huancayo compared with animals reared at sea level. The Griess reaction was used to determine NO levels based on nitrite stable metabolite concentrations. Our result make evident the participation of NO in MS in two animal models.

El óxido nítrico como nuevo sistema en la farmacología del estrés / Nitric oxide as a new system in the pharmacology of stress

El propósito de esta publicación es presentar evidencias científicas publicadas que confirman que el óxido nítrico (NO) participa activamente en la reacción del estrés y en los mecanismos genéticos de la adaptación. El NO se sintetiza a partir de la Larginina por la sintasa de óxido nítrico (NOS) y participa en un gran número de procesos fisiológicos: trasmisión de la señal en el cerebro, regulación del sistema cardiovascular, inmune, gastrointestinal y urogenital. Desde 1990, muchas evidencias indican que el NO participa en la regulación del aparato genético; y ahora existen muchos datos que muestran que los factores estresantes ambientales aumentan la producción de NO, lo cual sugiere que el incremento de la producción de NO es la respuesta del organismo a la reacción del estrés. Malyshev y Manuklina, en base al postulado de Meerson, definen al sistema de generación del NO como un nuevo nuevo sistema, nitroérgico, limitante del estrés en los humanos y animales, con las siguientes características: 1) se induce por el estrés, 2) es capaz de limitar la reacción de estrés, 3) tiene la capacidad de aumentar la resistencia a los factores ambientales, 4) la capacidad del NO de aumentar y de los inhibidores de la NOS a disminuir la resistencia al estrés y la adaptación de los organismos; y 5) capacidad para aumentar su actividad en el proceso de adaptación. Este nuevo escenario nos permite visionar un futuro promisorio en la investigación y desarrollo de medicamentos a base de plantas medicinales con propiedades de modular el sistema generador del NO; al mismo tiempo que hacemos las siguientes reflexiones: 1) ¿se puede utilizar al NO como un indicador del estrés?, si así fuera, 2) ¿se puede desarrollar alguna técnica apropiada para esta determinación? y, 3) ¿seremos capaces de percibir esta nueva oportunidad terapéutica para un mejor aprovechamiento de las plantas medicinales y los productos naturales?.

The intention of this publication is to present published scientific evidences that confirm that the nitric oxide (NO) actively participates in stress and the adaptation. NO is synthesized in the organism from L-arginine by the enzyme NO-synthase. NO participates in a great number of physiological processes: signal transmisision in the brain, regulation of cardiovascular, immune, gastrointestinal and urogenital systems. From the early 1990s very important proofs have appeared indicating that NO is involved in the regulation of genetic apparatus; and there is a lot of information that show that the stressful environmental factors increased the production of NO, it can be suggested that the increased NO production is a response of the organism to stress reaction. Malyshev and Manuklina, on the basis of Meerson’s postulate, define to the system of generation of NO as a newly recognized the NO-ergic stress-limiting system in the human beings and animals, with the following characteristics: 1) stress-inducibility, 2) capability to limit the stress reaction, 3) capability to increase the resistance to environmental factors, 4) capability of NO to increased and NO-synthase inhibitors to decrease the ressistance to stress and adaptability of the organism, and 5) capability to increase its activity in the process of adaptation. This information allows us visionar a promissory future in the search of medicines from medicinal plants capable of modulating the generating system of NO. Finally, we do the following reflections: 1) is it possible to use to NO as an indicator of the stress?, if this way out, 2) is it possible to develop some technology adapted for this determination? And, 3) will we be capable of taking advantage of this new therapeutic opportunity for the medicinal plants and the natural products?.

Niveles elevados de óxido nítrico en pollos de carne criados en forma artesanal / Elevated levels of nitric oxide in broilers reared in the traditional way

En nuestro país existe un consumo considerable de pollos de carne que proceden de la crianza artesanal; sin embargo, hasta ahora, no hay un sustento científico de las posibles implicaciones toxicológicas en la salud pública. Por lo tanto, nos propusimos conocer ¿cómo se encuentran los niveles de óxido nítrico (NO) en el plasma de pollos de carne criados en condiciones artesanales y, cuál es su posible origen enzimático?. Los animales proceden de granjas familiares ubicadas en Villa El Salvador (Lima). La determinación del NO fue indirectamente a través de la cuantificación de los nitritos mediante la reacción de Griess. Se utilizó al dietilditiocarbamato (DETC) como atrapador del NO, L-NAME como inhibidor inespecífico de la enzima sintasa del NO (NOS), y la aminoguanidina (AG) como inhibidor específico de la NOS inducible (iNOS). Los resultados sugieren que el origen de los niveles elevados de nitritos plasmáticos en pollos de carne que se están criando en condiciones artesanales sería de la iNOS, se requiere de trabajos adicionales para su confirmación definitiva. Se concluye que en pollos de carne criados en forma artesanal los niveles plasmáticos de NO se encuentran elevados.

In our country there exists a high consumption pf chickens of meat that come from the handcrafted upbringing; nevertheless, till now there is no a scientific sustenance of the posible toxicological implications, which this situation could have in the public health. For what, we proposed to know how they find the levels of nitric oxide (NO) in the plasma of chickens of meat raised in handcrafted conditions and, what is his possible enzymatic origin? The animals came from handcrafted farms located in Villa Salvador (Lima). The determination of NO was indirectly across the nitrites by means of Griess’s reaction. One used the dietilditiocarbamato (DETC) as trapping of NO, L-NAME as unspecific inhibitor of the sintasa of NO (NOS), and aminoguanidina (AG) like a specific inhibitor of NOS inducible (iNOS). The results suggest that the origin of the levels of plasmatic nitrites in chickens of meat that are growing up in handcrafted conditions they would be of the iNOS, it is needed of additional works for a definitive confirmation. One concludes that in chickens of meat raised in handcrafted form the plasmatic levels of NO are high.

Efecto del estrés medioambiental sobre los niveles plasmáticos de óxido nítrico y el peso en pollos de carne / Effect of environmental stress on plasma levels of nitric oxide and the weight in broilers

En trabajos previos hemos encontrado que los pollos que fueron criados en forma artesanal presentaron niveles de óxido nítrico elevados (NO). El objetivo de esta investigación fue comparar los niveles plasmáticos de NO en pollos de carne machos de la línea Ross criados en forma artesanal con los criados en condiciones controladas de granja, así como también los pesos. La determinación de la NO y del peso se realizó 5 días hasta los 45 días. Los resultados demuestran, que los pollos de carne criados artesanalmente presentan mayores niveles de NO desde los 10 hasta los 15 días de edad los niveles de nitratos son mayores de los 15 hasta los 25 días de edad. Los criados en granja, sus niveles de NO fueron bajos pero los pesos son óptimos, mientras que los criados en forma artesanal los pesos fueron bajos. Estos resultados demuestran que factores como la temperatura, ruido, rayos del sol, mal acondicionamiento e higiene le producen al pollo estrés medioambiental, que induce la sobreproducción de NO en los pollos de carne y disminuye la ganancia de peso.

Due to, to the high levels of nitric oxide (NO) in the plasma of the chickens of meat raised in not controlled conditions, one glide to determine the levels plasmatic of NO in the meat-type chickens exposed to the handcrafted raised and in controlled conditions (Farm), during the growth of the chickens and the factors that would cause the overproduction of NO. For the study, ware in use male meat-type of chickens, of the line Ross, proceeding from the handcrafted upbringing and of the upbringing in controlled conditions (farm). Was realized the analysis of the samples of blood and was weight to 15 chickens, every 05 days, up to 45 days. The results demonstrate, that the chickens of meat handmadely raised present majors levels of NO from the 10 up to 15 days of age and the levels of NO of the 15 up to 25 days of age. The raised in farm, the levels of NO were low and irregulars, but the weight was ideal, whereas the servants in handcrafted form the weight was low. By means of this investigation, ours results demonstrate that factors like the temperature, noises, sunbeams, evil conditioning and hygiene produced to the chickens environmental stress, which overproduced plasmatic levels of NO in the meat-type chickens, that reverberates in his weight.

Rol del óxido nítrico en la adaptación a la altura y la ascitis: una hipótesis / Role of the nitric oxide in the adjustment to the high altitude and the ascitis: a hypothesis

Nuestras investigaciones que se vienen realizando en diferentes alturas del Perú han puesto en evidencia que en óxido nítrico (NO) participa en el mal de altura tanto en los mamíferos como en aves, sin embargo, su participación en el síndrome ascítico aun no está definida. En ratas juveniles (RJ) se observó una sobreproducción de NO hasta la tercera semana de permanecer en la altura de 3.320 msnm (Huancayo); mientras que en ratas adultas la elevación fue, solamente, desde el segundo hasta al sétimo día. En pollos de carne de un día de edad (PB) expuestos a la misma altura se observó mortalidad por ascitis en un promedio del 20% y los sobrevivientes presentaron sobreproducción prolongada de NO hasta la cuarta semana. En cambio, en pollos juveniles y adultos la tendencia fue a disminuir sus niveles plasmáticos d NO; pero, después de permanecer algunas semanas aquí estos niveles se elevaron muy significativamente. A diferencia de estos resultados, pollos expuestos a la altura de 3.800 msnm (La Oroya) mostraron una disminución del NO en forma progresiva e irreversible: así como una mayor mortalidad por ascitis (100%, en menos de 30 días). La disminución del NO es más rápida a 4.818 msnm (Ticlio), aquí la muerte ocurre en pocas horas; sorprendentemente, cuando un grupo de pollos fueron retornados al nivel del mar (Lima) los niveles NO se elevaron temporalmente. “El NO participa en el proceso de adaptación a la altura; la disminución prolongada de su concentración por efecto del estrés medio ambiental es una causa de la ascitis que se observa en aun alto porcentaje de pollos de carne cuando son criados en la altura de nuestro país”. La comprobación de esta hipótesis facilitaría la implementación de nuevas estrategias terapéuticas. En esa dirección se encuentra trabajando nuestro laboratorio.

Our researches in different heights of Peru have put in evidence that the nitric oxide (NO) is taking part in the High altitude sikness both in the mammals and in the birds, nevertheless its participation in the ascites still is not definite. In juvenile rats an overproduction was observed of No up to the third week of remaining in the altitude of 3.320 mnsm (Huancayo); whereas in adult rats the increase was from the second one up to the seven day. In meat-type chickens of a day of age exposed to the same altitude the mortality by ascitis was in 20%; the survivors presented long overproduction of NO up to the fourth week. On the other hand, in juvenile and adult chickens the trend went to diminish his plasmatic levels of NO; but, after remaining some time here the levels rose very significantly. Unlike these results; chickens exposed 3.8000 m.a.s.l. (La Oroya) showed a decrease of NO in progressive and irreversible form, as well as a major mortality for ascitis (100%, in less than 30 days). The decrease is more rapid at 4.818 m.a.s.l. (Ticlio) here the death happens at a few hours, surprinsingly, when a group of chickens were returned at the level of the sea (Lima) the levels of NO rise temporarily. Taken together, this results supports strongly oue hypothesis: “ The NO takes part in the process of adjustment to the altitude; the long decrease of its concentrating for effect of the environmental stress is a reason of the ascitis that is observed in a high percentage of meat-type chickens when they are raised in the high altitude of our country. The checking of this hypothesis would facilitate the implementation of new therapeutic strategies. At this direction our laboratories is employed.

Nuevos resultados en el estudio de plantas de la amazonía peruana con actividad pigmentante de la piel del pollo de carne / New findings in the study of plants of the Peruvian Amazon with the skin pigmenting activity of chicken meat

El bosque tropical amazónico llama la atención al mundo y se constituye en todo un desafío para la ciencia. No solamente nos brinda sustancias bioactivas y alimentos, sino también otros productos que contribuyen a mejorar la calidad de vida de la humanidad. Por eso, estamos convencidos que la selva peruana es una fuente de pigmentantes alternativos para la avicultura mundial, en esa dirección estamos trabajando0. Después de haber ensayado con varias plantas que han evidenciado tener propiedades pigmentantes de la piel en pollos que fueron criados en la Merced (Chanchamayo), ahora presentamos los resultados obtenidos en pollos Cobb criados en la Facultad de Medicina Veterinaria de la UNMSM (Lima). El objetivo de este ensayo fue replicar las experiencias de la selva central en lo referente a la actividad pigmentante y determinar si el tratamiento modifica la ganancia de peso. A 50 pollos (machos y hembras) se suministró, desde los 30 hasta los 44 días de edad un extracto acuoso al 1 por ciento de hojas de una planta procedente de la amazonía peruana (PA). La evaluación se realizó a los 7 y 14 días del tratamiento. Los resultados demuestran en forma objetiva que la PA intensifica, a partir de los 7 días del tratamiento, la pigmentación del pollo de carne en comparación con los controles (dieta convencional); y no modifica la ganancia del peso.

The tropical Amazonian forest calls the attention to the world and is constituted in the whole challenge for the science. Not only it offers to us substances bioactivas and food, but also other products that help to improve the quality of life of the humanity. Because of it, we are sure that the Peruvian jungle is a source of pigments alternative for the global aviculture, at this direction we are employed. After having tested with several plants that they have demonstrated to have properties pigments of the skin in chickens that were raised in Merced (Chanchamayo), now we present the results obtained in Chickens Cobb raised in the Faculty of Veterinary Medicine of the UNMSM (Lima). The aim of this essay was to answer the experiences of the central jungle in what concerns the activity of pigmentation and to determine if this treatment modifies the profit of weight. 50 chickens (males and females) a watery extract was given from the 30 up to 44 days of age, 1 per cent of leaves of a plant proceeding from the Peruvian Amazonian (PA). The evaluation was realized to 7 and 14 days of the treatment. The results demonstrate I objective form that the PA intensifies, from 7 days of treatment, the pigmentation of the chicken of meat in comparison with the controls (conventional diet); and it does not modify the profit of weight.

La selva amazónica como fuente de pigmentos naturales para la avicultura mundial / The amazonian jungle as a source of natural pigments for the world aviculture

Las investigaciones etnofarmacológicas que estamos llevando a cabo desde hace varios años en la selva del Perú nos ha permitido plantear la hipótesis que las plantas utilizadas por los nativos para pigmentar su cuerpo, también pueden ser utilizadas para pigmentar la piel de los pollos de carne y la yema del huevo cuando son utilizdos por vía interna. Después de un adecuado screening hemos seleccionado algunas plantas que han demostrado in vivo estas propiedades (efectividad). No se trata de la Curcuma longa (palillo), Bixa orellana (achiote), tampoco de la Tagetes sp. (marigold). Se trata de especies que además, se usan ampliamente por sus propiedades medicinales (seguridad) y que contienen componentes bioactivos con estructuras químicas hidro y liposolubles lo cual hace que su efecto en la piel del ave se aprecie en pocos días (economía). Todo lo cual es muy ventajoso en comparación con las xantofilas que se vienen usando en la avicultura mundial. Los ensayos se estan realizando en la costa, sierra y selva con resultados muy alentadores; sin embargo, el no contar con un laboratorio adecuadamente equipado está dificultando el desarrollo de estos nuevos pigmentantes. Le correspode a la empresa privada involucrarse en esta iniciativa científica para poder acceder con ventaja competitiva a un gran mercado que tiene crecimiento sostenido.

Los niveles elevados de nitritos en pollos de carne proceden del óxido nítrico / The high levels of nitrites in chickens of meat come from the nitric oxide

El óxido nítrico (NO) es sintetizado por las células de los mamíferos y juega un rol crucial en la regulación homeostática del sistema inmune, neuronal y cardiovascular. Sin embargo, aún no conocemos si lo mismo ocurre en aves. En un trabajo previo, hemos reportado que los pollos Cobb sobreproducen nitritos (NO2-); por lo tanto, el objetivo de esta investigación fue determinar el origen químico de los niveles elevados de NO2- que se producen en pollos de carne cuando son criados en condiciones no controladas. Los pollos BBs (Cobb o Ross) fueron criados desde el primer día de edad hasta la sétima semana; a un grupo de pollos de una semana de edad se les administró dietilditiocarbamato (DETC) como un atrapador específico del NO; y la N - nitro-L- arginina metil éster y dexametazona como inhibidores de la sintasa del NO. Nuestros resultados indican que los NO2-proceden del NO.

Estudio basico de la flotacion de casiterita utilizando colectores anfoteros

Contenido: 1.Introduccion 2.Objetivo 3.Antecedentes 4.Fundamentos teoricos 5.Materiales y equipo utilizados 6.Resultados experimentales y discusiones 7.Conclusiones 8.Recomendaciones.