The Rumen And Its Microbes

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.

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.

This book offers an introduction to the microbes and microbial activity of the rumen. It offers an in-depth description of rumen bacteria, protozoa and fungi. Information is given on microbial concentrations and those factors which control or influence their numbers in the rumen. Both the synergism and negative effects resulting from microbial interactions are discussed.

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 ruminant and the rumen; the rumen bacteria; the rumen protozoa; the rumen anaerobic fungi; development of, and natural fluctuations in, rumen, microbial populations; energy yielding and consuming reactions; metabolism of nitrogen- containing compounds; polysaccharide degradation by rumen microorganisms;lipid metabolism of rumen, the genetics of rumen bacteria; microbe-microbe intercations; compartmentation in the rumen; manipulation of rumen fermentation; digestive disorders and nutritional toxicity;

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.

Two questions could not be avoided in the avant-propos of this book; (i) what is the importance to man of ruminant livestock, and (ii) what results of practical relevance in the growing mountain of scientific verbiage could be found in the Proceedings of this Symposium. Herbivores are an integral and critical part of the natural ecosystem which must be preserved because of their impact on human welfare. Wh at makes ruminants especially important to man is that they can thrive on fibrous forage and are thus the only viable enterprise over much of the earth's surface where crop growing is impracti cable. They contribute a wide array of products in addition to 50000 000 tonnes ofmeat (1977) and represent a 'capital reserve' that can be drawn upon in times of emergency: milk for example (450000000 tonnes) can make the difference between subsistence and starvation. About 60% of the world's meat and 80 % of the milk are produced by one third of the world ruminant population in the developed regions and as much as 99 % of the power for agriculture is provided by the ruminant population in developing countries. For the next two decades, a probable increase by 30 % for . cattle and buffalo and more than 40 % for sheep and goats is expected by improving health, fertility, nutrition and genetic potential rather than feed resources.