Influence of different supplements and sugarcane (Saccharum officinarum L.) cultivars on intake, digestible variables and methane production of dairy heifers under tropical conditions

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Biodigestão anaeróbia dos resíduos da produção avícola: cama de frangos e carcaças

O propósito deste trabalho foi avaliar a produção de biogás, bem como os potenciais de produção e a qualidade do biofertilizante obtido com a biodigestão anaeróbia dos resíduos cama de frangos e carcaças de aves pré-compostados. Para tanto, foram pré-compostados cama de frango e carcaças de aves mortas em uma composteira durante um período de 60 dias, período necessário para que ocorresse decomposição prévia das carcaças e assim fosse possível manipular o material para abastecer os biodigestores. Após este período, o material foi utilizado para abastecer os biodigestores batelada de campo com capacidade de 60 litros de material em fermentação. Para o processo de biodigestão anaeróbia, foram efetuadas análises dos teores de sólidos totais (ST), sólidos voláteis (SV), composição química do efluente, potenciais de produção, além do número mais provável (NMP) de coliformes totais e termotolerantes no afluente e efluente. Os potenciais médios de produção de biogás foram: 0,073; 0,152 e 0,141m³.kg-1 de material, SV e ST adicionados, respectivamente. Foram observadas reduções acima de 99% no NMP de coliformes totais e termotolerantes, sendo observado NMP de 3,7 x 10(5) g-1 no início e 7,45 x 10² g-1 no final.

Effect of tannin levels in sorghum silage and concentrate supplementation on apparent digestibility and methane emission in beef cattle

This study evaluated the effect of diets containing sorghum silages with higher (HT) and lower-tannin (LT) concentrations supplemented with concentrate or urea on intake, digestibility, ruminal digestibility, methane emission and rumen parameters in beef cattle. Four treatments were distributed according to a 2 x 2 factorial arrangement in a duplicate 4 x 4 Latin square: LT sorghum silage + urea, LT sorghum silage + concentrate, HT sorghum silage + urea, and HT sorghum silage + concentrate. Total digestibility of the organic matter was higher when concentrate was included in the diet (0.749 and 0.753 in the LT and HT treatments, respectively). It was observed lower ruminal apparent digested matter of neutral detergent fiber in HT diets. There was no effect of tannin levels on digestibility and methane emission. The supplementation with concentrate in the LT diet decreased gas losses as a function of gross energy intake in comparison to the supplementation of the diet with urea. These results suggest the potential of concentrate supplementation to minimize energy loss as methane emission by ruminants and increase the efficiency of energy utilization. (c) 2006 Elsevier B.V. All rights reserved.

Methane and carbon dioxide seasonal cycles at urban Brazilian inland sites

Methane and carbon dioxide seasonal cycles during years 1998 and 1999 at two Brazilian urban and inland sites are presented. The mixing ratio averages over the studied period of time were 1.80 ppm CH4 and 384.7 ppm CO2. A comparison is made between continental averages and the averages of the three nearest global network background sites of NOAA-CMDL comprising Ascension Island, Namibia and Easter Island. Inland sites had 0.08 ppm or 4.9% more CH4 and 19.0 ppm or 4.9% more CO2 than background over the same time span. The CH4 summer minimum observed in remote sites was also detected inland. During the month of October 98 and 99 inland mixing ratios were frequently similar to background.

Synthesis and characterization of the mer-[RuCl3(NO)(dppb)] isomer. X-ray structures of fac-[RuCl3(NO)(dppm)], cis-[RuCl2(dppm)2] and mer-[RuCl3(NO)(dppb)] [dppm=1,2-Bis(diphenylphosphino)methane and dppb=1,4-Bis(diphenylphosphino)butane]

The fac-[RuCl3(NO)(dppm)] (1) and cis-[RuCl2(dppm)2] (2) complexes were obtained with co-crystallization in the solid state from the reaction of RuCl3(NO) with the diphosphine in dichloromethane. mer-[RuCl3(NO)(dppb)] (3) was obtained from [RuCl3(dppb)(H2O)] by bubbling NO for 30 min in the same solvent. The crystal and molecular structures of these three compounds have been determined from X-ray studies. © Elsevier Science Ltd.

Improved activity and stability of Ce-promoted Ni/γ-A1 2O3 catalysts for carbon dioxide reforming of methane

The CO2 reforming of CH4 was carried out over Ni catalysts supported on γ-Al2O3 and CeO 2-promoted γ-Al2O3. The catalysts were characterized by means of surface area measurements, TPR, CO2 and H2 chemisorption, XRD, SEM, and TEM. The CeO2 addition promoted an increase of catalytic activity and stability. The improvement in the resistance to carbon deposition is attributed to the highest CO2 adsorption presented by the CeO2 addition. The catalytic behavior presented by the samples, with a different CH4/CO2 ratio used, points to the CH4 decomposition reaction as the main source of carbon deposition.

Physical-chemical and thermodynamic analyses of steam reforming of ethanol to hydrogen production

The steam reforming is one of most utilized process of hydrogen production because of its high production efficiencies and its technological maturity. The use of ethanol for this purpose is a interesting option because this is a renewable and less environmentally offensive fuel. The objective of this study is evaluate the physical-chemical, thermodynamic and environmental analyses of steam reforming of ethanol. whose objective is to produce 0.7 Nm3/h of hydrogen to be used by a PEMFC of l kW. In this physical-chemical analysis, a global reaction of ethanol was considered. That is, the superheated ethanol and steam, at high temperatures, react to produce hydrogen and carbon dioxide. Beyond it's the simplest form to study the steam reforming of ethanol to hydrogen production, it's the case where occurs the highest production of hydrogen (the product to be used by fuel cells) and carbon dioxide, to be eliminated. But this reaction isn't real and depends greatly on the thermodynamic conditions of reforming, technical features of reformer system and catalysts. Other products generally formed (but not investigated in this study) are methane, carbon monoxide, among others. It was observed that the products is commonly produced in the moment when the reaction attains temperatures about 206°C (below this temperature, the reaction trend to the reaetants, that is, from hydrogen and carbon dioxide to steam and ethanol) and the advance degree of this reaction increases when the temperature of reaction also increases and when its pressure decreases. It's suggested reactions at about 600°C or higher. However, when the temperature attains 700°C, the stability of this reaction is occurred, that is, the production of reaction productions attains to the limit, that is the highest possible production. In temperatures above 700°C, the use of energy is very high for produce more products, having higher costs of production that the suggested temperature. The indicated pressure is 1 atm., a value that allows a desirable economy of energy that would also be used for pressurization or depressurization of steam reformer. In exergetic analysis, it's seem that the lower irreversibililies occur when the pressure of reactions are lower. However, the temperature changes don't affect significantly the irreversibilites. Utilizing the obtained results from this analysis, it was concluded that the best thermodynamic conditions for steam reforming of ethanol is the same conditions suggested in the physical-chemical analysis. The exergetic and first law efficiencies are high on the thermodynamie conditions studied.

Functional nanostructured catalysts based on the niobates to the dry methane reforming and ethylene homologation reactions

Catalytic activity and selectivity of niobate-based nanostructured materials were investigated. Dry methane reforming (DMR) and ethylene homologation reaction (EHR) were selected as test reactions. KSr 2Nb5O15, Sr2NaNb5O 15 and NaSr2(NiNb4)O15 δ niobate powders were prepared by the high energy ball milling method and calcined in a reductor atmosphere. N2 adsorption isotherms, X-ray diffraction and infrared spectroscopy characterization was performed. Hydrogen pretreated niobates showed from low to moderate catalytic initial activity in DMR's test, nevertheless the materials were deactivated rapidly and the kinetic parameters associated to deactivation were estimated. Otherwise, non-treated catalysts showed a high initial activity in EHR's test and KSr2Nb 5O15 catalyst requires 24 h to the total deactivation with a high selectivity to form propylene. A reaction mechanism to the propylene formation is discussed. © 2012 Elsevier Ltd. All rights reserved.

Methane emissions and estimates of ruminal fermentation parameters in beef cattle fed different dietary concentrate levels

Using sorghum silage, the effect of roughage/concentrate ratios was evaluated on nutrient intake, digestibility, ruminal parameters and methane production by beef cattle. Three treatments (0, 30 and 60% of concentrate in DM of the diet) were distributed in three Latin squares, with nine animals and three periods. Dry matter intake increased as the grain concentration in diet increased; pH showed opposite behavior. Methane emissions were lower for animals fed the diet exclusively with sorghum silage as compared with those fed 30% of concentrate, but was similar to that of animals receiving 60% of concentrate. Losses of ingested gross energy as methane were reduced by 33% when grain concentration was increased in the diet. Concentrations of propionic and butyric acids were greater in diets with grain concentrate; acetic acid concentration was not affected. Concentrate in diet increases available energy for the metabolism, measured by lower losses of ingested gross energy as ruminal methane. © 2013 Sociedade Brasileira de Zootecnia.

Produção in vitro de metano, dióxido de carbono e oxigênio utilizando líquido ruminal de bovinos alimentados com diferentes rações

Pós-graduação em Zootecnia - FCAV

Tropical tanniniferous legumes used as an option to mitigate sheep enteric methane emission

This study presents the first results from Brazil using SF6 tracer technique adapted from cattle to evaluate the capability of condensed tannin (CT) present in three tropical legume forages, Leucaena leucocephala (LEU), Styzolobium aterrimum (STA), and Mimosa caesalpiniaefolia Benth (MIM) to reduce enteric CH4 production in Santa Ins sheep. Twelve male lambs [27.88 +/- 2.85 kg body weight (BW)] were allocated in individual metabolic cages for 20-day adaptation followed by 6 days for measuring dry matter intake (DMI) and CH4 emission. All lambs received water, mineral supplement, and Cynodon dactylon v. coast-cross hay ad libitum. The treatments consisted of soybean meal (710 g/kg) and ground corn (290 g/kg) [control (CON)]; soybean meal (150 g/kg), ground corn (30 g/kg), and Leucaena hay (820 g/kg) (LEU); soybean meal (160 g/kg), ground corn (150 g/kg), and Mucuna hay (690 g/kg) (STA); and soybean meal (280 g/kg), ground corn (190 g/kg), and Mimosa hay (530 g/kg) (MIM); all calculated to provide 40 g/kg CT (except for CON). DMI (in grams of DMI per kilogram BW per day) was lower for LEU (22.0) than CON (29.3), STA (31.2), and MIM (31.6). The LEU group showed emission of 7.8 g CH4/day, significantly lower than CON (10.5 g CH4/day), STA (10.4 g CH4/day), and MIM (11.3 g CH4/day). However, when the CH4 emission per DMI was considered, there were no significant differences among treatments (0.37, 0.36, 0.33, and 0.35 g CH4/g DMI/kg BW/day, respectively, for CON, LEU, STA, and MIM). The sheep receiving STA had shown a tendency (p = 0.15) to reduce methane emission when compared to the CON group. Therefore, it is suggested that tropical tanniniferous legumes may have potential to reduce CH4 emission in sheep, but more research is warranted to confirm these results.

Effect of lipid sources with different fatty acid profiles on the intake, performance, and methane emissions of feedlot Nellore steers

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Methane emission by Nellore cattle subjected to different nutritional plans

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Marandu grass management and supplementation on performance and methane mitigation of Nellore bulls

Pós-graduação em Zootecnia - FCAV

Quantification of ruminal microbiota and production of methane and carbonic dioxide from diets with inclusion of glycerin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)