This book offers an in-depth description of different groups of microbes (i.e. bacteria, protozoa, fungi and viruses) that exist in the rumen microbial community, and offers an overview of rumen microbiology, the rumen microbial ecosystem of domesticated ruminants, and rumen microbial diversity. It provides the latest concepts on rumen microbiology for scholars, researchers and teachers of animal and veterinary sciences. With this goal in mind, throughout the text we focus on specific areas related to the biology and complex interactions of the microbes in rumen, integrating significant key issues in each respective area. We also discuss rumen manipulation with plant secondary metabolites, microbial feed additives, utilization of organic acids, selective inhibition of harmful rumen microbes, and ‘omics’ approaches to manipulating rumen microbial functions. A section on the exploration and exploitation of rumen microbes addresses topics including the current state of knowledge on rumen metagenomics, rumen: an underutilized niche for industrially important enzymes and ruminal fermentations to produce fuels. We next turn our attention to commercial applications of rumen microbial enzymes and to the molecular characterization of euryarcheal communities within an anaerobic digester. A section on intestinal disorders and rumen microbes covers acidosis in cattle, urea/ ammonia metabolism in the rumen and nitrate/ nitrite toxicity in ruminant diets. Last, the future prospects of rumen microbiology are examined, based on the latest developments in this area. In summary, the book offers a highly systematic collection of essential content on rumen microbiology.

The Preface to the first edition of this book explained the reasons for the publication of a comprehensive text on the rumen and rumen microbes in 1988. The microbes of the ruminant's forestomach and those in related organs in other animals and birds provide the means by which herbivorous animals can digest and obtain nutriment from vegetation. In turn, humans have relied, and still do rely, on herbivores for much of their food, clothing and motive power. Herbivores also form the food of carnivorous animals and birds in the wild. The importance of the rumen microorganisms is thus apparent. But, while a knowledge of rumen organisms is not strictly neces sary for the normal, practical feeding of farm animals, in recent years there has been much more emphasis on increasing the productivity of domesti cated animals and in rearing farm animals on unusual feedstuffs. Here, a knowledge of the reactions of the rumen flora, and the limits to these reactions, can be invaluable. In addition, anaerobic rumen-type microor ganisms are found in the intestines of omnivores, including humans, and can be implicated in diseases of humans and animals. They are also found in soils and natural waters, where they playa part in causing pollution and also in reducing it, while the same organisms confined in artificial systems are essential for the purification of sewage and other polluting and toxic wastes.

The Rumen and Its Microbes is a contribution to the ecology of this important microbial habitat. Relatively few microbial habitats have been subjected to a thorough quantitative ecological analysis. The rumen fermentation is peculiarly suitable because of its relatively constant and continuous nature and because of the very rapid rates of conversion of organic matter. Although analysis of the ruminant-microbe symbiosis is still far from complete, knowledge is sufficient for formulation of principles and for identification and measurement of important parameters. The first eight chapters of the book include a description of the rumen and its microbes, their activities, and the extent of these activities. This basic biology provides a framework in which applications to agriculture can be evaluated. These applications are discussed in the last four chapters: host metabolism, variation in the rumen, possible practical applications, and abnormalities in rumen function.

Part 1 summarises advances in analysing the rumen microbiome. Part 2 reviews recent research on different types of rumen microbiota. Part 3 discusses the way the rumen processes nutrients whilst Part 4 explores nutritional strategies to optimise rumen function.

Asaresultofvarioushumanactivities,suchasincreaseinhumanpopulation,decrease in arable land due to soil degradation, urbanization, industrialization and associated increase in the demand for livestock products, dramatic changes are occurring in the global ruminant livestock sector. These changes includeshift inthesize of regional livestock populations and in the types of management and feeding systems under which ruminant livestock are held, and increased demand of a wider range of quality attributes from animal agriculture, not just of the products themselves but also of the methods used in their production. The livestock sector will need to respond to newchallengesofincreasinglivestockproductivitywhileprotectingenvironmentand human health and conservingbiodiversity and natural resources. The micro-organisms in the digestive tracts of ruminant livestock have a profound in?uence on the conversion offeedinto end products, which can impact on the- imal and theenvironment. As the livestock sector grows particularly in developing countries, there will be an increasing need to understand these processes for b- ter management and use ofbothfeed and other natural resources that underpinthe development of sustainable feeding systems.

All ruminants are dependent on the microorganisms that live in their forestomach - the rumen - to break down ingested feed constituents into a form that the host animal can utilize. Protozoa are part of this complex ruminal population and are essential for the nutritional well-being and productivity of the host ruminant. Over 30 different genera (nearly 300 species) of protozoa from the rumen ecosystem have been described since their initial discovery nearly 150 years ago. This book brings together, for the first time, the available information on these protozoa. It comprehensively describes the characteristic anatomical features of value for their identification and includes detailed sections on techniques and methodologies for the isolation and cultivation of these fastidious, oxygen-sensitive microorganisms. Their occurrence, biochemistry, physiology, and role in the ruminal ecosystem are fully reviewed. Particular emphasis is given to potential improvement of the nutrition and productivity of the host ruminant through manipulation of the protozoal population and its activities.

Ruminants were domesticated in the Middle East about 10,000 years ago and have since become an inseparable part of human diet, society, and culture. Ruminants can transform inedible plant fiber and non-protein nitrogen into meat, milk, wool and traction, thus allowing human utilization of non-tillable land and industrial by-products. The nutritional flexibility of ruminants is conferred by the rumen´s complex microbial community. Driven by rising income and population growth in emergent economies, the global demand for livestock products, including milk and meat from ruminants, has been increasingly growing, and is predicted to continue growing in the next few decades. The increase in production necessary to satisfy this rising demand is putting much pressure on already dwindling natural resources. There are also concerns about the emissions of methane and nitrous oxide, potent greenhouse gases associated to ruminant production. The need to make ruminant production more efficient in the use of natural resources poses a big challenge to ruminant science, and within it, rumen microbiology. Recent years have seen important advances in basic and applied rumen microbiology and biochemistry. The knowledge generated has significant implications for the efficiency and sustainability of ruminant production and the quality of ruminant products for human health. The present compilation is an update of recent advances in rumen microbiology and ruminant digestion and fermentation, including original research, reviews, and hypothesis and theory articles. We hope that the experimental results, discussion, models and ideas presented herein are useful to foster future research contributing to sustainable ruminant production.