Perfil da textura da carne de cordeiros de dois grupos genéticos alimentados com diferentes níveis de inclusão de casca de soja.

Resumo: O objetivo do trabalho foi avaliar a textura da carne de cordeiros da raça Texel e Ideal alimentados com diferentes níveis de casca de soja na dieta. Foram utilizados 40 cordeiros machos não castrados, sendo 20 provenientes da raça Texel e 20 da raça Ideal. As dietas corresponderam a diferentes proporções de casca de soja (% MS) em substituição ao volumoso: (0%; 33,5%; 66,5% e 100% de casca de soja). O grupo genético afetou somente a elasticidade da carne (P<0,05), sendo superior para os animais da raça Ideal demostrando ser aproximadamente 9% mais elástica que a carne de cordeiros Texel. Os níveis de inclusão de casca de soja na dieta afetaram a dureza, gomosidade e mastigabilidade da carne, apresentando comportamento quadrático e ponto de máxima no nível de 66,5%, tornando a carne menos suculenta, menos macia, necessitando assim, maior força na mastigação. Embora a raça afete a elasticidade da carne, assim como a dieta contendo 66,5% de casca de soja as outras variáveis da textura, esses valores não depreciam a carne. ]Profile of the texture of lamb meat from two genetic groups fed with different inclusion levels of soybean hulls]. Abstract: The objective of this study was to evaluate the texture of lamb meat of the Texel breed and the Ideal breed fed with different levels of soybean hulls on the diet. Forty uncastrated male lambs, 20 from of the Texel breed and 20 from of the Ideal breed were used. The diets consisted of different proportions of soybean hulls (% DM) replacing the forage: (0%, 33.5%, 66.5% and 100% of soybean hulls). The genetic group has just affected the elasticity of the meat (P <0.05), being higher for the animals Ideal breed demonstrating to be about 9% more elastic than Texel lambs meat. The inclusion levels of soybean hulls in the diet affected the toughness, gumminess and chewiness of the meat, with quadratic response and maximum point at level of 66.5%, making meat less juicy, less softness, requiring bigger strength in chewing. Although the breed has affected the elasticity of the meat, even as the diet containing 66.5% of soybean hulls affecting other variables of the texture, these values didn?t depreciate the lamb?s meat

Características da carcaça e dos componentes não carcaça de cordeiros oriundos de parto simples ou duplo.

Resumo: Um experimento foi conduzido com o objetivo de avaliar as características da carcaça e dos componentes não carcaça de cordeiros nascidos de parto simples ou duplo. Dezesseis cordeiros mestiços Texel × Ile de France, machos não castrados, foram desmamados aos 56 dias de idade e abatidos com aproximadamente 28kg de peso corporal. Imediatamente após o abate, cada componente corporal foi pesado separadamente, sendo as carcaças avaliadas após 24 horas de refrigeração a 2°C. Os cordeiros oriundos de parto simples apresentaram superioridade no peso e nos rendimentos da carcaça, além de maior área de olho de lombo. Por outro lado, proporcionalmente ao peso de corpo vazio, o rúmen é maior em cordeiros nascidos de parto duplo, o que resulta incremento da proporção de conteúdo gastrintestinal ao abate. Os resultados deste estudo indicam que, quando abatidos a um mesmo peso, cordeiros oriundos de parto simples possuem carcaças de melhor qualidade, em comparação a cordeiros nascidos de parto gemelar. [Carcass and non-carcass traits of single and twin lambs]. Abstract: An experiment was conducted to evaluate the carcass and non-carcass traits of single and twin lambs. Sixteen Texel × Ile de France crossbred, non-castrated male lambs were weaned at 56 days of age and slaughtered at 28kg of body weight. Immediately after the slaughter each body component was individually weighed, while carcasses were evaluated after a 24h period of refrigeration at 2°C. Single lambs presented higher values of carcass weight and carcass dressing percentage. Moreover, the Longissimus muscle area was also greater for single lambs. On the other hand, as a proportion of empty body weight, rumen was greater for twin lambs, increasing their gastrointestinal content at slaughter. The results of this study indicated that at a same slaughter weight single lambs have better quality carcasses in comparison with those from twin lambs

Reviews and syntheses: Heterotrophic fixation of inorganic carbon – significant but invisible flux in environmental carbon cycling

Heterotrophic CO2 fixation is a significant yet underappreciated CO2 flux in environmental carbon cycling. In contrast to photosynthesis and chemolithoautotrophy – the main recognized autotrophic CO2 fixation pathways – the importance of heterotrophic CO2 fixation remains enigmatic. All heterotrophs – from microorganisms to humans – take up CO2 and incorporate it into their biomass. Depending on the availability and quality of growth substrates, and drivers such as the CO2 partial pressure, heterotrophic CO2 fixation contributes at least 1 %–5 % and in the case of methanotrophs up to 50 % of the carbon biomass. Assuming a standing stock of global heterotrophic biomass of 47–85 Pg C, we roughly estimate that up to 5 Pg C might be derived from heterotrophic CO2 fixation, and up to 12 Pg C yr−1 originating from heterotrophic CO2 fixation is funneled into the global annual heterotrophic production of 34–245 Pg C yr−1. These first estimates on the importance of heterotrophic fixation of inorganic carbon indicate that this pathway should be incorporated in present and future carbon cycling budgets.</p

Fundamental research questions in subterranean biology

Five decades ago, a landmark paper inSciencetitledThe Cave Environmentheralded caves as ideal natural experimental laboratories in which to develop and address general questions in geology, ecology, biogeography, and evolutionary biology. Although the 'caves as laboratory' paradigm has since been advocated by subterranean biologists, there are few examples of studies that successfully translated their results into general principles. The contemporary era of big data, modelling tools, and revolutionary advances in genetics and (meta)genomics provides an opportunity to revisit unresolved questions and challenges, as well as examine promising new avenues of research in subterranean biology. Accordingly, we have developed a roadmap to guide future research endeavours in subterranean biology by adapting a well-established methodology of 'horizon scanning' to identify the highest priority research questions across six subject areas. Based on the expert opinion of 30 scientists from around the globe with complementary expertise and of different academic ages, we assembled an initial list of 258 fundamental questions concentrating on macroecology and microbial ecology, adaptation, evolution, and conservation. Subsequently, through online surveys, 130 subterranean biologists with various backgrounds assisted us in reducing our list to 50 top-priority questions. These research questions are broad in scope and ready to be addressed in the next decade. We believe this exercise will stimulate research towards a deeper understanding of subterranean biology and foster hypothesis-driven studies likely to resonate broadly from the traditional boundaries of this field.Peer reviewe

Tracking down carbon inputs underground from an arid zone Australian calcrete.

Freshwater ecosystems play a key role in shaping the global carbon cycle and maintaining the ecological balance that sustains biodiversity worldwide. Surficial water bodies are often interconnected with groundwater, forming a physical continuum, and their interaction has been reported as a crucial driver for organic matter (OM) inputs in groundwater systems. However, despite the growing concerns related to increasing anthropogenic pressure and effects of global change to groundwater environments, our understanding of the dynamics regulating subterranean carbon flows is still sparse. We traced carbon composition and transformations in an arid zone calcrete aquifer using a novel multidisciplinary approach that combined isotopic analyses of dissolved organic carbon (DOC) and inorganic carbon (DIC) (δ13CDOC, δ13CDIC, 14CDOC and 14CDIC) with fluorescence spectroscopy (Chromophoric Dissolved OM (CDOM) characterisation) and metabarcoding analyses (taxonomic and functional genomics on bacterial 16S rRNA). To compare dynamics linked to potential aquifer recharge processes, water samples were collected from two boreholes under contrasting rainfall: low rainfall ((LR), dry season) and high rainfall ((HR), wet season). Our isotopic results indicate limited changes and dominance of modern terrestrial carbon in the upper part (northeast) of the bore field, but correlation between HR and increased old and 13C-enriched DOC in the lower area (southwest). CDOM results show a shift from terrestrially to microbially derived compounds after rainfall in the same lower field bore, which was also sampled for microbial genetics. Functional genomic results showed increased genes coding for degradative pathways-dominated by those related to aromatic compound metabolisms-during HR. Our results indicate that rainfall leads to different responses in different parts of the bore field, with an increase in old carbon sources and microbial processing in the lower part of the field. We hypothesise that this may be due to increasing salinity, either due to mobilisation of Cl- from the soil, or infiltration from the downstream salt lake during HR. This study is the first to use a multi-technique assessment using stable and radioactive isotopes together with functional genomics to probe the principal organic biogeochemical pathways regulating an arid zone calcrete system. Further investigations involving extensive sampling from diverse groundwater ecosystems will allow better understanding of the microbiological pathways sustaining the ecological functioning of subterranean biota

The role of organisms in hyporheic processes : gaps in current knowledge, needs for future research and applications

Fifty years after the hyporheic zone was first defined (Orghidan, 1959), there are still gaps in the knowledge regarding the role of biodiversity in hyporheic processes. First, some methodological questions remained unanswered regarding the interactions between biodiversity and physical processes, both for the study of habitat characteristics and interactions at different scales. Furthermore, many questions remain to be addressed to help inform our understanding of invertebrate community dynamics, especially regarding the trophic niches of organisms, the functional groups present within sediment, and their temporal changes. Understanding microbial community dynamics would require investigations about their relationship with the physical characteristics of the sediment, their diversity, their relationship with metabolic pathways, their inter- actions with invertebrates, and their response to environmental stress. Another fundamental research question is that of the importance of the hyporheic zone in the global metabolism of the river, which must be explored in relation to organic matter recycling, the effects of disturbances, and the degradation of contaminants. Finally, the application of this knowledge requires the development of methods for the estimation of hydro- logical exchanges, especially for the management of sediment clogging, the optimization of self-purification, and the integration of climate change in environmental policies. The development of descriptors of hyporheic zone health and of new metrology is also crucial to include specific targets in water policies for the long-term management of the system and a clear evaluation of restoration strategies

Brazilian cave heritage under siege

info:eu-repo/semantics/publishe

Toward improved bioremediation strategies: Response of BAM-degradation activity to concentration and flow changes in an inoculated bench-scale sediment tank.

Compound-specific isotope analysis (CSIA) can reveal mass-transfer limitations during biodegradation of organic pollutants by enabling the detection of masked isotope fractionation. Here, we applied CSIA to monitor the adaptive response of bacterial degradation in inoculated sediment to low contaminant concentrations over time. We characterized Aminobacter sp. MSH1 activity in a flow-through sediment tank in response to a transient supply of elevated 2,6-dichlorobenzamide (BAM) concentrations as a priming strategy and took advantage of an inadvertent intermittence to investigate the effect of short-term flow fluctuations. Priming and flow fluctuations yielded improved biodegradation performance and increased biodegradation capacity, as evaluated from bacterial activity and residual concentration time series. However, changes in isotope ratios in space and over time evidenced that mass transfer became increasingly limiting for degradation of BAM at low concentrations under such stimulated conditions, and that activity decreased further due to bacterial adaptation at low BAM (μg/L) levels. Isotope ratios, in conjunction with residual substrate concentrations, therefore helped identifying underlying limitations of biodegradation in such a stimulated system, offering important insight for future optimization of remediation schemes