bluuebunny/crossref_metadata_2025_split huggingface dataset:
Metagenomic approaches in harnessing gut microbial diversity.
Authors: Thulasi A. , Lyju Jose Lyju Jose , Chandrasekharaiah M. , Rajendran D. , Prasad C. S. 
Published: May 2015

Abstract

The mechanisms involved in the digestive process of the rumen are complex, and are accomplished by a diverse and dynamic group of microbes. Microbial diversity in the rumen has been predicted to enhance the resistance of the network of metabolic pathways by increasing the number of genes encoding the pathway, enabling the ecosystem to stabilize more rapidly after change to a new equilibrium. The more resistant metabolic pathways, and the more diverse source of novel pathways, will make the microbial system more resilient. A variety of molecular methods based on direct isolation and analysis of nucleic acids, proteins and lipids from environmental samples have been discovered, and they reveal structural and functional information about microbial communities. Molecular approaches such as genetic fingerprinting, metagenomics, meta proteomics, metatranscriptomics and proteogenomics are vital for discovering and characterizing the vast diversity of microbes and understanding their interactions with biotic and abiotic environmental factors. In this chapter, efforts are made to discover the possible applications of metagenomic tools for exploring the complex microbial diversity of ruminal microbes.
Perspective on livestock-generated GHGs and climate.
Authors: Takahashi J. 
Published: May 2015

Abstract

The greenhouse gases (GHGs) attributed to agriculture and animal agriculture are methane (CH4) and nitrous oxide (N2O). The relative absorptivity of the infrared radiation of carbon dioxide (CO2) is about 21-fold and 310-fold higher than for each molecule of CH4 or N2O, respectively. As the absorptivity in both gases is not saturated like CO2, the contribution of CH4 and N2O to the greenhouse effect have therefore been prospectively increasing linearly, because atmospheric increases in the concentration of both gases correlate closely with human activities, and the world population is currently expanding to more than 7 billion. Rumen CH4 production emitted to the atmosphere can be accounted as the biggest anthropogenic source. The abatement mechanism of rumen CH4 emission may be divided into direct and indirect suppression of methanogens in the rumen. The most significant strategy to mitigate rumen CH4 emission in an indirect manner is to promote alternative metabolic pathways to dispose of the reducing power, competing with methanogenesis for H2 uptake. In an attempt to identify natural manipulators with the efficacy to mitigate rumen CH4 emission, efficient prebiotics and probiotics have been developed in various institutions instead of ionophores in respect to food safety. The relatively lower molecular weight compounds produced by Lactobacillus plantarum have recently revealed the ability to suppress rumen methanogenesis. Some tropical and subtropical legume trees fed to cattle and buffalo as a protein source, due to their high protein content, are rich in secondary metabolites such as saponin and tannin, which is a type of polyphenol, etc. Some of them have been reported to abate rumen CH4 production remarkably well in vitro or in vivo. In some cases, however, experimental results are in agreement but may not match. Meta-analysis might be useful to integrate statistically the experimental results from independent studies for comprehensive understanding in the next stage of research. Although the inventory assessment of N2O is still ongoing, animal manures, including those from monogastrics, have been listed as a significant contributor. The incomprehensible fates of organic and inorganic nitrogen compounds contained in the aerobic composting of animal manures may confuse an accurate evaluation of the actual emission of N2O from animal manures. Of late, there has been an urgent need for renewable energy production using anaerobic digesters to capture biogas (CH4) from animal effluent. Most manure nitrogen during fermentation has been converted to an inorganic form in the digested slurry.
Carbon footprints of food of animal origin.
Authors: Flachowsky G. 
Published: May 2015

Abstract

Animal production contributes substantially to global greenhouse gas emissions (about 14.5%). So-called carbon footprints (CFs) consider the greenhouse gas potential of climate-relevant gases (e.g. CO2 × 1; CH4 × 23; N2O × 296), which is given in carbon dioxide (CO2)-equivalent g-1 or kg-1 of product or unit of edible protein. CFs may help to assess the greenhouse gas emissions associated with the production of food of animal origin such as milk, meat, eggs or fish, and they may contribute to sensitizing producers and consumers to a more resource-efficient and environmentally friendly production and consumption of food of animal origin and to avoiding food wastage. The highest CFs per unit edible protein are calculated for products of growing ruminants (beef and lamb), followed by milk, pork, eggs and poultry meat, with the lowest values. Discrepancies in the results of various studies are explained mainly by different system boundaries, allocation methods and computation of emissions, especially with regard to land-use changes, enteric methane (CH4) and nitrous oxide (N2O) emissions. A more standardized approach for CF calculations would be a very useful tool to compare CFs between production systems, regions and countries, and as an indicator for food labelling. The production of food of animal origin is a very complex process, and a selective consideration, i.e. focusing on single factors, does not provide an assessment that reflects the complexity of the subject.
Climate change: impacts on livestock diversity in tropical countries.
Authors: Banik S. , Pankaj P. K. , Naskar S. 
Published: May 2015

Abstract

The effect of changing climate will not only be confined to limited production, and the productivity of agricultural commodities, but will also have far-reaching consequences on dairy, meat, wool and other animal products. The impact of climate change on the livestock sector as a whole will be felt more in tropical countries compared to temperate countries, largely because of the structure of production system and economics. The resultant pressure, both direct and indirect, is likely to result in further dilution of livestock diversity, which would specially affect the nutritional security and livelihood of small and marginal farmers. The challenge is to sustain genetic diversity and productivity by different adaptation strategies like production adjustment, breeding strategies, alteration of management systems, developing appropriate policies, scientific intervention and capacity building of livestock owners. In light of concerns over the impacts of climate change and climate variability, this chapter provides an overview of the opportunities for adaptation and mitigation strategies in tropical climatic conditions.
Climate change: impact of meat production.
Authors: Musalia L. M. 
Published: May 2015

Abstract

Between 1961 and 2009, the world recorded a continued increase in the demand for meat, driven by the fast growth in population, economic improvement, changes in eating habits and rapid urbanization. This has resulted in improved livestock production that is projected to continue even into the future. However, raising animals for food has been identified as a major contributor to climate change. As more meat is produced to satisfy the increasing demand, it is important to understand its effect on climate change, which continues to be a threat to food security. Livestock production contributes 14.5% of the total greenhouse gases (GHGs) that originate directly from the animal in the form of enteric emissions (39%), or indirectly from activities in the meat production value chain like animal feed production and processing (45%), manure decomposition (10%) and slaughter, processing and transportation of animal products (6%). The amount of GHGs emitted in meat production depends on the type of feed and the capability of the animals to digest and utilize feeds, thus minimizing the amount of waste excreted. The production of meat is a very inefficient system where animal proteins require 11 times more fossil fuel compared to plant protein. The efficiency of meat production reduces in the order of fish, poultry, pork and beef. Efficient meat production systems also cut down on the emissions associated with the production of massive feeds. Meat production systems involving ruminant animals and feeding fibrous or poor-quality feeds contribute significantly to enteric emission and manure production, and the inefficiency of feed utilization and meat from these systems has a high GHG effect.
Enteric methane emission: status, mitigation and future challenges - an Indian perspective.
Authors: Raghavendra Bhatta Raghavendra Bhatta , Malik P. K. , Prasad C. S. 
Published: May 2015

Abstract

1% per annum. To stabilize this greenhouse gas in the atmosphere, global CH4 production needs to be reduced by 10-20%. Ruminants fed on low-quality feed/fodder produce over 75% of the CH4 generated by ruminants worldwide. Strategic supplementation to improve digestive efficiency in these animals could halve this CH4 production per unit of feed consumed. Supplementation to improve the efficiency of feed utilization coupled with increased product output may thus reduce CH4 production per unit of milk or meat by a factor of 4-6. The dietary/nutritional strategy that improves productivity with no potential negative effects on livestock health and production is cost-effective and has a better chance of being adopted. Other strategies (biotechnologies, additives) are promising, but the diversity and plasticity of the functions of the rumen bacterial and methanogenic communities may be the limiting factor for their successful application. In addition, the environmental impacts of strategies should also be taken into consideration. A global vision of production systems that considers all greenhouse gas emissions from the animal up to the farm scale, as well as grassland use, is essential. Further, the sustainability of CH4-suppressing strategies is an important issue. An effort is made in this chapter to address enteric CH4 emissions and their current status. An overview on the possible ameliorative strategies has also been given.
Ionophores: a tool for improving ruminant production and reducing environmental impact.
Authors: Bell N. , Wickersham T. , Sharma V. , Callaway T. 
Published: May 2015

Abstract

Ruminal fermentation is an inherently inefficient process converting up to 12% of dietary carbon and energy into end products (e.g. CH4) that are largely unusable by the animal. Ruminant nutritionists seek to modify fermentation, specifically by increasing ruminal propionic acid yield, reducing methanogenesis and decreasing ruminal proteolysis and deamination of dietary proteins in order to improve production efficiency. To date, a variety of methods have been investigated in an effort to meet these objectives. Carboxylic polyether compounds, 'ionophores', are an effective means of decreasing enteric CH4 emissions when included in ruminant diets. Although ruminant nutritionists have historically focused on feeding ionophores to increase efficiency and profitability, recent attention has focused on the ability of ionophores to impact global greenhouse gas production. This chapter examines the use of ionophores in cattle diets for the mitigation of enteric CH4 production. Issues like ionophore resistance and the impact of ionophore feeding on human health are also addressed.
Acetogenesis as an alternative to methanogenesis in the rumen.
Authors: Gagen E. J. , Denman S. E. , McSweeney C. S. 
Published: May 2015

Abstract

Bacteria capable of producing acetate from H2 and CO2 using the acetyl-CoA pathway (4H2+2CO2 → CH3COOH+2H2O) are known as acetogens. They have been found in a variety of anaerobic ecosystems, including sediments, wastewater treatment systems, soils and animal gut systems. In recent years, acetogens have received attention as a hydrogenotrophic population that may play a role in reducing methane (CH4) emissions from ruminant animals. During ruminal fermentation, methanogenic archaea reduce CO2 (4H2+CO2 → CH4+2H2O) or methylated compounds to CH4. Ruminal methanogenesis represents a loss of 2-12% of gross energy of ingested feed and contributes significantly to global greenhouse gas emissions. If methanogenesis could be suppressed in the rumen, acetogenesis may serve as an effective alternative hydrogen sink, resulting in an energy gain for the ruminant through the production of acetate. Acetogenesis is the dominating hydrogenotrophic pathway in other gut systems such as those of humans, pigs, termites and potentially some native Australian marsupials. The latter are of particular interest as they exhibit foregut fermentation analogous to that of ruminants, though resulting in significantly less CH4 production, suggesting the functioning of alternative hydrogen sinks to methanogenesis. Recent molecular investigations of the bovine and ovine rumen and the tammar wallaby forestomach revealed the presence of a diversity of functional gene sequences associated with reductive acetogenesis that demonstrate only low similarity to sequences from presently isolated authentic rumen acetogens. Giving the natural rumen acetogen population a competitive advantage over methanogens may be a strategy for establishing reductive acetogenesis rather than methanogenesis as the major hydrogen sink in the rumen. Methanogen inhibitors may aid this process, allowing hydrogen in the rumen to accumulate to levels where it can be utilized by acetogens. Previous researchers have found that reductive acetogenesis was enhanced in the presence of methanogen inhibitors in ruminal incubations. Also, acetogen enhancers may provide acetogens with an advantage over methanogens in the rumen. Continued study into the factors affecting ruminal acetogens and their interactions with methanogens is certainly needed.
Immunization and tannins in livestock enteric methane amelioration.
Authors: Uyeno Y. 
Published: May 2015

Abstract

The complexity of the rumen microbial ecosystem supports the efficient conversion of various carbohydrates to volatile fatty acids for fulfilling host energy requirement via stepwise disposal of hydrogen (H2) through the reduction of carbon dioxide (CO2) to methane (CH4). Although, this mechanism is indispensable for rumen homeostasis, CH4 production in ruminants has attracted a great deal of attention due to its contribution to the greenhouse gas effect and global warming. Various strategies have therefore been considered for its mitigation. Rumen methanogen targeting vaccination is a promising means of reducing CH4 emissions by decreasing the number or activity of rumen methanogens. However, trials of this strategy have provided inconsistent results, and need for further consideration of the composition, function and microbial interactions within the ecosystem. Alternatively, to establish a more efficient way for the mitigation of CH4 emission, systematic intervention in rumen microbial populations by a combination of vaccination and other chemical means may also be feasible. Although some of the CH4 abatement strategies have shown efficacy in vivo, more research is needed to make any of these approaches applicable to animal production systems. This chapter provides the background to the diversity and plasticity of functions of the rumen bacterial and methanogenic communities, as well as some of the CH4 abatement options that aim to manipulate the rumen community, including immunization and other concepts.
Phage therapy in livestock methane amelioration.
Authors: Gilbert R. A. , Ouwerkerk D. , Klieve A. V. 
Published: May 2015

Abstract

Viruses of prokaryotes (phages) are obligate microbial pathogens that can, in the lytic phase of development, infect and lyse their respective bacterial or archaeal hosts. As such, these viruses can reduce the population density of their hosts rapidly, and have been viewed as possible agents of biological control (phage therapy). Phage therapy is becoming increasingly important as a means of eradicating or controlling microbial populations as the use of antibiotics and chemical treatments becomes both less effective and less publicly acceptable. Phage therapy has therefore been raised as a potential strategy to reduce methane (CH4) emissions from ruminants, providing an innovative biological approach, harnessing the potent, yet targeted, biocidal attributes of these naturally occurring microbial predators.
Summary.
Authors: Malik P. K. , Bhatta R. , Saravanan M. , Baruah L. 
Published: May 2015

Abstract

This chapter summarizes the full content of this book where contributors have addressed various aspects of livestock production vis-à-vis climate change. Improving livestock production and productivity is the need of the hour to accomplish the ever increasing demand of the populace. Climate change appears to be a major constraint in this endeavour as it severely affects livestock directly or indirectly. Further, livestock itself is accountable for the climatic variations and negative environmental complications of climate change by dispensing large quantities of greenhouse gases into the atmosphere. The implications of climate change on livestock, the involvement of livestock in climate change, mitigation approaches and adaptation strategies for minimizing the adverse impact and reducing enteric methane (CH4) emissions debated in the various chapters of this book are summarized here.
Status of resistance to Bt cotton in China: cotton bollworm and pink bollworm.
Authors: Gao YuLin Gao YuLin , Liu ChenXi Liu ChenXi , Wu YiDong Wu YiDong , Wu KongMing Wu KongMing 
Published: May 2015

Abstract

Transgenic cotton that expresses a gene derived from the bacterium Bacillus thuringiensis (Bt) has been deployed for combating the cotton pests Helicoverpa armigera and Pectinophora gossypiella since 1997 in China. The pest management tactics associated with Bt cotton have resulted in a drastic reduction in insecticide use. However, the evolution of resistance by the pests threatens the continued success of Bt cotton. The development of resistance to Bt is of great concern, and there is a vast body of research in this area aimed at ensuring the continued success of Bt cotton. Here, we review studies on the evolution of Bt resistance in these two bollworms, focusing on the commercial release of Bt cotton varieties in China, and the biochemical and molecular basis of Bt resistance. We also discuss resistance management strategies, and monitoring programmes implemented in China and other countries.
Resistance of Busseola fusca to Cry1Ab Bt maize plants in South Africa and challenges to insect resistance management in Africa.
Authors: Berg J. van den , Campagne P. 
Published: May 2015

Abstract

The evolution of resistance to Bacillus thuringiensis (Bt) maize by the African stem borer, Busseola fusca, in South Africa highlighted the importance of the development of appropriate integrated resistance management (IRM) strategies for stem borers in Africa. Landscape heterogeneity is characteristic of African agroecosystems. This heterogeneity, in addition to between field and within-field spatial mosaics resulting from variable gene expression in Bt maize, will provide challenges to managing resistance evolution of the lepidopteran stem borers that attack maize. Adding to this landscape heterogeneity is the cultivation of open-pollinated maize varieties (OPVs) and bimodal rainfall patterns that allow two maize cropping seasons each year in many subtropical and tropical areas. The role that these factors, as well as aspects such as low-dose expression events, refuge compliance, the genetic bases of resistance, pest behaviour, host plant range and farming practices, may play in the evolution of stem borers to Bt maize in Africa are addressed in this chapter.
Roles of insect midgut cadherin in Bt intoxication and resistance.
Authors: Fabrick J. A. , Wu YiDong Wu YiDong 
Published: May 2015

Abstract

Genetically engineered crops producing Bacillus thuringiensis (Bt) proteins for insect control target major insect pests. Bt crops have improved yields and their use reduces the risks associated with the application of conventional insecticides. However, the evolution of resistance to Bt toxins by target pests threatens the long-term success of such transgenic crops. Insects resistant to Bt Cry toxins have been selected in the laboratory and field-evolved resistance has been reported for economically important insects in several regions of the world. Although the mechanisms of resistance have not been reported for all cases, the most common mechanism involves changes in larval midgut target sites that probably reduce binding to Bt toxins. The binding of Cry toxins to midgut cadherin represents an important step in Bt intoxication for many insects and mutations in the cadherin gene can result in resistance to Bt toxins. Here, we highlight the roles that insect midgut cadherins play in Bt Cry intoxication and review cases where changes in cadherin are involved with resistance to Cry toxins. Furthermore, we emphasize the importance of understanding the underlying molecular basis of Bt intoxication and resistance to Bt, and the implications of fundamental knowledge for resistance management strategies.
The role of proteolysis in the biological activity of Bt insecticidal crystal proteins.
Authors: Zalunin I. A. , Elpidina E. N. , Oppert B. 
Published: May 2015

Abstract

The crystal toxins (Cry) produced by the bacterium Bacillus thuringiensis (Bt) have been successfully used in both spray formulations and transgenic crops to control some of the most problematic insect pests, as has been discussed in previous chapters. The δ-endotoxins of Bt are functionally active in the insect gut and interact with and are processed by proteolytic enzymes. The structure of Cry proteins has specific features that not only permit them to retain their biological activity in the hostile environment of the insect gut, but also to use the process of proteolysis in the solubilization and activation of Cry protoxins. Because the proteolysis of Cry proteins is critical to their biological activity, we review the literature on studies related to insect and mammalian proteases and their effects on toxin structure and toxicity.
The development and prospect of discovery of Bt toxin genes.
Authors: Zhang Jie Zhang Jie , Shu ChangLong Shu ChangLong , Wang ZeYu Wang ZeYu 
Published: May 2015

Abstract

Bacillus thuringiensis (Bt) Cry protein-based insect control has proven to be effective in reducing the use of chemical insecticides and in increasing crop yields. However, Bt crops increase selection pressure for resistant insects and accelerate their succession. The discovery and application of different Bt toxins that have no cross-resistance with known toxins has been proposed as a strategy for the management of resistant insects. Additionally, the discovery of novel Bt toxins with a new insecticidal spectrum will control insect succession. In fact, the discovery of new Bt toxins is one of the most important areas in Bt research, and the most advanced molecular biology methods available have been applied to this task. In this chapter, we summarize the published methods for Bt toxin discovery.