Fatores afetando o consumo e utilização de forrageiras de baixa qualidade por ruminantes - revisão.

A quantidade máxima de alimento capaz de ser consumida por um ruminante e de grande importância para o produtor. De um modo geral, quanto maior for o consumo, menor será a quantidade de alimento necessário por unidade de produção. Este fato e que caracteriza a eficiência produtiva de um animal. A conseqüência econômica seria que maiores lucros estariam dependentes da capacidade dos ruminantes em digerir alimentos fibrosos mais baratos e disponíveis em maiores quantidades. O Maximo consumo de uma forragem pelo ruminante depende, primariamente, das taxas de escoamento do rúmen da celulose e hemicelulose. Estas taxas, por sua vez, depende de vários fatores que interferem na atividade da flora microbiana do rúmen, quais sejam: evolução do processo de lignificação com o estágio de maturação das forrageiras, parcial ausência de nutrientes para a microflora como nitrogênio ou minerais e a presença em excesso de agentes bacteriostáticos. Dada a sua importância econômica e cientifica, este assunto vem sendo estudado extensivamente por nutricionistas e fisiologistas em varias partes do mundo, gerando uma enorme gama de conceitos relacionados ao binômio animal-planta, parte dos quais foram reunidos no presente trabalho de revisão.bitstream/item/131377/1/fatores-afetando-o-consumo.pd

Determination of digestible energy values and fermentabilities of dietary fibre supplements: a European interlaboratory study in vivo

The performance of methods to determine energy conversion factors for dietary fibre (DF) supplements and fermentability (D) values of their non-starch polysaccharides (NSP) was investigated. Heats of combustion, digestible energy (DE) and D values were determined on five DF supplements in five European laboratories on five separate occasions. In each instance the DF supplements were fed to juvenile male VVistar rats at two doses, 50 and 100 g/kg basal diet, for 3 weeks with food and faeces collected in the 3rd week. Among-laboratory variations in heats of combustion (DHC<) were <2%. DE values (kJ/g dry weight) at the upper and lower doses respectively were: 10·4 and 9·9 for a high-methoxyl apple pectin, 9·5 and 9·4 for a sugar-beet DF supplement, 12·2 and 12·7 for soyabean DF supplement, 38 and 4·0 for maize bran, and 0·3 and 0·3 for Solka-floc cellulose. Variations among laboratories, among occasions and among animals were <1, <2 and <2·5 kJ/g respectively. The among-occasion: among-laboratory variance ratio for DE was 0·5, suggesting the method performed equally well in all laboratories. There was no evidence of learning or fatigue in the performance of the method. D values were also independent of dose and at the high and lower doses were: pectin 0·92 and 0·95, sugar-beet NSP 0·68 and 0·68, soyabean NSP 0·86 and 0·88, maize bran 0·17 and 0·18, cellulose 0·07 and 0·06. Among-laboratory variance tended to increase with decreasing fermentability and ranged from 0·03 to 0·18. The DE and D data were not significantly different from a previously proposed relationship DE = 0·7 × DHc × D, where DHc is the heat of combustion of the supplement. We conclude that while the among-laboratory variation in the D of difficult-to-ferment NSP is too large for the reliable prediction of energy value the method for the direct determination of DE is both reproducible and repeatable, that DE is independent of dosage of DF supplement up to 100 g/kg diet, and that it is safe to discriminate between energy values with a precision of 3 kJ/g. The conversion of both DE and D to net metabolizable energy for the purpose of food labelling, tables and databases is describe

High-E_T dijet photoproduction at HERA

The cross section for high-E_T dijet production in photoproduction has been measured with the ZEUS detector at HERA using an integrated luminosity of 81.8 pb-1. The events were required to have a virtuality of the incoming photon, Q^2, of less than 1 GeV^2 and a photon-proton centre-of-mass energy in the range 142 < W < 293 GeV. Events were selected if at least two jets satisfied the transverse-energy requirements of E_T(jet1) > 20 GeV and E_T(jet2) > 15 GeV and pseudorapidity requirements of -1 < eta(jet1,2) < 3, with at least one of the jets satisfying -1 < eta(jet) < 2.5. The measurements show sensitivity to the parton distributions in the photon and proton and effects beyond next-to-leading order in QCD. Hence these data can be used to constrain further the parton densities in the proton and photon.Comment: 36 pages, 13 figures, 20 tables, including minor revisions from referees. Accepted by Phys. Rev.

Feasibility, acceptability and effectiveness of integrated care for COPD patients: a mixed methods evaluation of a pilot community-based programme.

The aim of this study was to assess the feasibility, acceptability and effectiveness of a pilot COPD integrated care programme implemented in Valais, Switzerland. The programme was adapted from the self-management programme Living Well with COPD, and included the following elements: self-management patient-education group sessions, telephone and medical follow-ups, multidisciplinary teams, training of healthcare professionals, and evidence-based COPD care. A process and outcome evaluation of the pilot phase of the programme was conducted by means of qualitative and quantitative methods. Reach (coverage, participation rates), dosage (interventions carried out), fidelity (delivered as intended) and stakeholders' acceptance of the programme were evaluated through data monitoring and conduct of focus groups with patients and healthcare professionals. Effectiveness was assessed with pre-post analyses (before and after the intervention). The primary outcome measures were; (1) generic and disease-specific quality of life (36-Item Short Form Health Survey, Chronic Respiratory Questionnaire); and (2) hospitalisations (all-cause and for acute exacerbations) in the past 12 months. Secondary outcomes included self-efficacy, number of exacerbations and exercise capacity. Finally, controlled pre-post comparisons were also made with patients from the Swiss COPD Cohort for three common outcome measures (dyspnoea [mMRC score], number of exacerbations and smoking status). During the first 2 years of the programme, eight series of group-based education sessions were delivered to 57 patients with COPD in three different locations of the canton of Valais. Coverage objectives were achieved and attendance rate at the education sessions was high (83.6%). Patients' and healthcare professionals' reported a high degree of satisfaction, except for multidisciplinarity and transfer of information. Exploration of the effectiveness of this pilot programme suggested positive pre-post results at 12 months, with improvements in terms of health-related quality of life, self-efficacy, exercise capacity, immunisation coverage and Patient Assessment of Chronic Illness Care score. No other outcome, including the number of hospital admissions, differed significantly after 12 months. We observed no differences from the control group. The evaluation demonstrated the feasibility and acceptability of the programme and confirmed the relevance of mixed method process evaluation to adjust and improve programme implementation. The introduction of multidisciplinary teams in a context characterised by fragmentation of care was identified as the main challenge in the programme implementation and could not be achieved as expected. Despite this area for improvement, patients' feedback and early effectiveness results confirmed the benefits of COPD integrated care programmes emphasising self-management education

Inclusive jet cross sections and dijet correlations in D∗±D^{*\pm} photoproduction at HERA

Inclusive jet cross sections in photoproduction for events containing a $D^*$ meson have been measured with the ZEUS detector at HERA using an integrated luminosity of $78.6 {\rm pb}^{-1}$. The events were required to have a virtuality of the incoming photon, $Q^2$, of less than 1 GeV$^2$, and a photon-proton centre-of-mass energy in the range $130<W_{\gamma p}<280 {\rm GeV}$. The measurements are compared with next-to-leading-order (NLO) QCD calculations. Good agreement is found with the NLO calculations over most of the measured kinematic region. Requiring a second jet in the event allowed a more detailed comparison with QCD calculations. The measured dijet cross sections are also compared to Monte Carlo (MC) models which incorporate leading-order matrix elements followed by parton showers and hadronisation. The NLO QCD predictions are in general agreement with the data although differences have been isolated to regions where contributions from higher orders are expected to be significant. The MC models give a better description than the NLO predictions of the shape of the measured cross sections.Comment: 43 pages, 12 figures, charm jets ZEU

Minimization of free radical damage by metal catalysis of multivitamin/multimineral supplements

Multivitamin/multimineral complexes are the most common dietary supplements. Unlike minerals in foods that are incorporated in bioorganic structures, minerals in dietary supplements are typically in an inorganic form. These minerals can catalyze the generation of free radicals, thereby oxidizing antioxidants during digestion. Here we examine the ability of a matrix consisting of an amino acid and non-digestible oligosaccharide (AAOS) to blunt metal-catalyzed oxidations. Monitoring of ascorbate radical generated by copper shows that ascorbate is oxidized more slowly with the AAOS matrix than with copper sulfate. Measurement of the rate of oxidation of ascorbic acid and Trolox® by catalytic metals confirmed the ability of AAOS to slow these oxidations. Similar results were observed with iron-catalyzed formation of hydroxyl radicals. When compared to traditional forms of minerals used in supplements, we conclude that the oxidative loss of antioxidants in solution at physiological pH is much slower when AAOS is present