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Summary Since 1944, the National Research Council has published energy and the six classes of nutrients. This is followed by 10 editions of the Nutrient Requirements of Swine. The pub- a chapter on the use of computer models to determine nu- lication has guided nutritionists and other professionals in trient requirements of swine. The remaining chapters cover academia and the swine and feed industries in developing and factors that influence nutrient utilization and responses to implementing nutritional and feeding programs for swine. nutrients and also the tables of requirements and nutrient The swine industry has undergone considerable changes composition. since the tenth edition was published in 19981 and some of The first chapter deals with energy. After describing the the requirements and recommendations set forth at that time classical scheme of partitioning energy from gross to net are no longer relevant or appropriate. This eleventh edition energy and its use in swine nutrition, the application of com- has been revised to reflect these changes. puter modeling to defining energy requirements is discussed. The task given to the committee is presented in Appendix The section on net energy has been revised substantially to B. In brief, the committee was asked to prepare a report that calculate net energy from digestible and metabolizable en- evaluates the scientific literature on the energy and nutrient ergy and from the chemical composition of feedstuffs. The requirements of swine in all stages of life. Other elements of new chapter contains discussions of the effects of immuno- the task included: information about feed ingredients from castration and ractopamine on energy utilization. the biofuels industry and other new ingredients, requirements Chapter 2, on proteins and amino acids, begins with a for digestible phosphorus (P) and concentrations of digest- discussion of the distinction between dietary essential and ible P in feed ingredients, a review of the effects of feed dietary nonessential amino acids and also the amino acids additives and the effects of feed processing, and strategies to whose dietary essentiality is conditional on other dietary increase nutrient retention and thus reduce fecal and urinary components and the physiological state of the animal. excretions that could contribute to environmental pollution. Sources of amino acids, both intact proteins and crystalline The study was supported by grants from the Illinois Corn amino acids, are then reviewed. The chapter examines the Marketing Board, the Institute for Feed Education & Re- various means of determining and expressing amino acid search, the National Pork Board, the Nebraska Corn Board, requirements (including empirical approaches, the ideal the Minnesota Corn Growers Association, the U.S. Food and protein concept, and factorial calculations) and reviews ex- Drug Administration, and by internal NRC funds derived periments to determine amino acid requirements of growing from sales of publications in the Animal Nutrition Series. pigs, sows, and boars. To accomplish the task, the text has been expanded con- Lipids, which were discussed within the energy chapter siderably to enlarge on existing topics and to add new topics. of the previous edition, are now given a chapter of their own Nutrient requirement tables have been revised and revamped (Chapter 3). The chapter begins with a discussion of lipids to reflect new research findings. The computer models that as a source of energy and the effects of dietary fat on swine generate estimates of energy and nutrient requirements have performance throughout the life cycle and then reviews the undergone major updates and the tables of feed composition specific effects of essential and bioactive fatty acids. The have been revised completely with a comprehensive review effects of fat intake on pork fatty acid composition are then of new information. The report begins with chapters on discussed and the calculations of iodine value and iodine value product are described. The final section of the chapter 1NRC (National Research Council). 1998. Nutrient Requirements of reviews quality measures of fat such as oxidation status and Swine, Tenth Edition. Washington, DC: National Academy Press. lipid analysis. 1
2 NUTRIENT REQUIREMENTS OF SWINE Carbohydrates were also covered in the energy chapter animal feed is regulated by the Food and Drug Administra- in the previous edition but are now reviewed in Chapter 4. tion (FDA) and some of the key FDA documents are cited Although swine do not have specific requirements for di- in the chapter. etary carbohydrates or fiber, most of the energy in pig diets Nutrient utilization may be influenced by how ingredients originates from carbohydrates of plant origin. The chapter are processed and how diets are prepared. This topic is ad- describes the major categories of carbohydrates, their diges- dressed in Chapter 12. The effects of mechanical process- tion, and the absorption of energy-yielding nutrients. ing, such as extrusion, grinding, and pelleting, on nutrient Water, sometimes described as the forgotten nutrient, is digestibility and pig performance are reviewed. Although reviewed in Chapter 5. The majority of the chapter is devoted most forms of processing, especially of ingredients with to the water requirements of all classes of swine, but there high contents of complex carbohydrates, increase pig per- are also sections on the functions of water, turnover of water, formance, the benefits have to be weighed against the costs and water quality. of the processing. The mineral nutrition of swine remains an active area Chapter 13 reviews the digestibility of nutrients and en- of research. Chapter 6 provides an update on new findings ergy by swine. Topics covered are protein and amino acids, for both macro- and microminerals. Other issues, such as lipids, carbohydrates, P, and energy. The chapter describes bioavailability and the use of certain minerals as pharmaco- the reasons for measuring digestibility and the primary logical agents, are also reviewed. methods used. Values for the digestibility of ingredients fed An update of the 1998 review of vitamin requirements is to swine are included in the tables of nutrient composition. provided in Chapter 7. The chapter is divided into fat-soluble The topic of feeding practices that minimize nutrient ex- and water-soluble vitamins. The relative bioavailability and cretion was introduced in the previous edition of the report, stability of vitamins used in feeds are also covered. There is and it has been expanded in Chapter 14 to include additional also discussion of toxicity and maximum tolerable levels for information on the influence of nutrition on nutrient excre- vitamins where data are available. tion and the environment. Nutrients discussed are nitrogen, The use of computer models to estimate energy and amino Ca and P, trace minerals, sulfur, and carbon. The effects of acid requirements was introduced in the previous edition of diet formulation on gaseous emissions, especially so-called this publication. The three models developed then (growing- greenhouse gases and ammonia, are also reviewed. finishing pigs, gestating sows, and lactating sows) have been In Chapter 15, research priorities are identified, includ- updated and expanded. As described in Chapter 8, the three ing specific areas and topics where research is needed to models are now mechanistic, dynamic, and deterministic in add new information or to confirm or refute data that are representing the biology of nutrient and energy utilization limiting. Many areas of research needs are documented, at the whole-animal level. In addition to energy and amino but the most important needs relate to amino acid, Ca, and acid requirements, the new models estimate requirements P requirements of all categories of pigs, with the greatest for calcium (Ca) and P. Other new features are the inclusion emphasis on the sow. in the growing pig model of the effects of including racto- Chapter 16 contains a series of tables of the nutrient pamine and immunization of entire males against boar taint. requirements of all classes of swine. Requirements are ex- The fundamental concepts represented in the models and pressed on an âas-fedâ basis. The committee critically evalu- the specific equations used in the calculations are described ated published studies to arrive at the estimates presented. in this chapter. As such, values in these tables are the best estimates of the The expansion of the biofuels industry, especially the pro- committee rather than an average of literature values. As duction of ethanol from corn, has resulted in large amounts in previous editions, the estimated nutrient requirements in of coproducts (sometimes called byproducts) that are now this publication are minimum standards without any safety used in animal feeding. Chapter 9 reviews information on allowances. Therefore, they are not intended to be considered the feeding value of these products for swine. Although the as recommended allowances. Professional nutritionists may emphasis is on coproducts from corn and soybean meal, choose to increase the levels of some of the more critical other plant and animal coproducts are also covered. nutrients to include âmargins of safetyâ in some circum- Chapter 10 addresses nonnutritive feed additives, such as stances (this comment does not apply to selenium because antimicrobial agents and exogenous enzymes. This chapter it is regulated by the FDA in the United States). Another is an update of material in the previous edition with new important point is that, for minerals and vitamins, the esti- information on several different categories of substances. mated requirements include the amounts of these nutrients An issue of increasing concern, making headlines in 2007 that are present in the natural feedstuffs and are not estimates because of the adulteration of pet food with melamine, is of amounts of nutrients to be added to diets. both the accidental and deliberate contamination of animal Chapter 17 consists of tables of feed ingredients for 122 feeds. Chapter 11 reviews feed contaminants and divides feedstuffs commonly fed to swine, including average com- them into three primary groups: chemical, biological, and position values. These tables have been completely revised physical. In the United States, the safety and adequacy of since the previous edition and are presented on individual
SUMMARY 3 pages for each ingredient. The literature was reviewed with represents the major cost of swine production. Inefficient emphasis during the last 15 years to arrive at ingredient nutrition utilization reduces profitability and efficiency and composition. If no new data were available, then the search can harm the environment. This report represents a compre- was extended to older literature. In some instances, no data hensive review of the most recent information available on were found; in those instances, combinations of data from swine nutrition and ingredient composition that will allow other published tables were used as sources of information. optimum swine production. New ingredients resulting from All livestock industries need to focus on efficient, profit- ethanol production are described, as well as feed contami- able, and environmentally conscious production, and the nants and environmental concerns. Use of this report will be swine industry is no exception. The nutrition of swine plays a an invaluable guide to support efficient and environmentally major role in each of these areas of production, and diet cost aware swine production.