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Overview
Energy, amino acids, minerals, vitamins, and water are needed by pigs for body maintenance, growth, reproduction, and lactation. Synthesis of muscle and adipose tissue, bone, hair, skin, and other body components, resulting in accretion of water, protein, lipid, and ash, is dependent upon an adequate dietary supply of nutrients. Pigs must be provided these essential nutrients in adequate amounts and in forms that are palatable and efficiently utilized in order for optimal growth, reproduction, and lactation to occur.
Since 1944, the National Research Council has published nine editions of Nutrient Requirements of Swine. This publication has guided nutritionists and other professionals in academia and the swine and feed industries in developing and implementing nutritional and feeding programs for swine. This tenth edition continues that tradition, but the format of this edition is quite different from that of previous ones. The text has been expanded with new sections that address contemporary issues, and the tables are more comprehensive. A new approach using integrated mathematical equations (models) was utilized to generate estimates of energy and amino acid requirements, and a computer program and software allow the user to create tables of nutrient requirements for swine of a specific body weight and level of productivity.
The first chapter deals with energy and reviews new information on digestible energy (DE), metabolizable energy (ME), and net energy (NE) requirements of swine. Equations for predicting DE, ME, and NE from chemical components are presented. New information on factors affecting energy requirements of swine also is included in this chapter.
In the chapter on proteins and amino acids (Chapter 2), much of the discussion relates to lysine, the first-limiting amino acid in most diets for pigs, and to new information on lysine requirements. The concept of ''ideal ratios" of essential amino acids to lysine for maximum lean tissue synthesis in growing pigs and optimal productivity in gestating and lactating sows is described. Discussion of bioavailability of amino acids, on a true and apparent ileal digestibility basis, has been expanded. A section on amino acid requirements of boars is now included.
Chapter 3 addresses the use of mathematical models to estimate energy and amino acid requirements of swine. This chapter describes the modeling approach that was taken by the subcommittee to generate the amino acid requirements of growing-finishing pigs from 20 to 120 kg body weight and for gestating and lactating sows. The growth model is based on the pig's lean growth rate and it estimates the daily true ileal digestible lysine needed to support maximum protein accretion at a given body weight. The dietary lysine requirement is then estimated based on the pig's daily feed intake, which, in turn, is based on body weight, gender, environmental conditions, and DE concentration of the diet. Estimates of the requirements for other essential amino acids are based on the ideal ratio of each to lysine for maintenance and protein accretion. The gestation model estimates the energy and amino acid requirements of sows based on their breeding weight, targeted gestational weight gain, and litter size. The lactation model estimates requirements based on the sow's postfarrowing weight, lactational weight change, and daily litter weight gain, a reflection of the amount of milk production.
Chapters on minerals and vitamins were updated with results from research studies reported since the previous edition. Chromium is recognized as an essential trace mineral for swine. The sodium and chlorine requirements of the young pig and the manganese requirement of the gestating and lactating sow were increased, and new information on the bioavailability of minerals is presented. The vitamin E and folacin requirements of gestating and lactating sows were increased, based on new research information.
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Overview
Energy, amino acids, minerals, vitamins, and water are needed by pigs for body maintenance, growth, reproduction, and lactation. Synthesis of muscle and adipose tissue, bone, hair, skin, and other body components, resulting in accretion of water, protein, lipid, and ash, is dependent upon an adequate dietary supply of nutrients. Pigs must be provided these essential nutrients in adequate amounts and in forms that are palatable and efficiently utilized in order for optimal growth, reproduction, and lactation to occur.
Since 1944, the National Research Council has published nine editions of Nutrient Requirements of Swine. This publication has guided nutritionists and other professionals in academia and the swine and feed industries in developing and implementing nutritional and feeding programs for swine. This tenth edition continues that tradition, but the format of this edition is quite different from that of previous ones. The text has been expanded with new sections that address contemporary issues, and the tables are more comprehensive. A new approach using integrated mathematical equations (models) was utilized to generate estimates of energy and amino acid requirements, and a computer program and software allow the user to create tables of nutrient requirements for swine of a specific body weight and level of productivity.
The first chapter deals with energy and reviews new information on digestible energy (DE), metabolizable energy (ME), and net energy (NE) requirements of swine. Equations for predicting DE, ME, and NE from chemical components are presented. New information on factors affecting energy requirements of swine also is included in this chapter.
In the chapter on proteins and amino acids (Chapter 2), much of the discussion relates to lysine, the first-limiting amino acid in most diets for pigs, and to new information on lysine requirements. The concept of ''ideal ratios" of essential amino acids to lysine for maximum lean tissue synthesis in growing pigs and optimal productivity in gestating and lactating sows is described. Discussion of bioavailability of amino acids, on a true and apparent ileal digestibility basis, has been expanded. A section on amino acid requirements of boars is now included.
Chapter 3 addresses the use of mathematical models to estimate energy and amino acid requirements of swine. This chapter describes the modeling approach that was taken by the subcommittee to generate the amino acid requirements of growing-finishing pigs from 20 to 120 kg body weight and for gestating and lactating sows. The growth model is based on the pig's lean growth rate and it estimates the daily true ileal digestible lysine needed to support maximum protein accretion at a given body weight. The dietary lysine requirement is then estimated based on the pig's daily feed intake, which, in turn, is based on body weight, gender, environmental conditions, and DE concentration of the diet. Estimates of the requirements for other essential amino acids are based on the ideal ratio of each to lysine for maintenance and protein accretion. The gestation model estimates the energy and amino acid requirements of sows based on their breeding weight, targeted gestational weight gain, and litter size. The lactation model estimates requirements based on the sow's postfarrowing weight, lactational weight change, and daily litter weight gain, a reflection of the amount of milk production.
Chapters on minerals and vitamins were updated with results from research studies reported since the previous edition. Chromium is recognized as an essential trace mineral for swine. The sodium and chlorine requirements of the young pig and the manganese requirement of the gestating and lactating sow were increased, and new information on the bioavailability of minerals is presented. The vitamin E and folacin requirements of gestating and lactating sows were increased, based on new research information.
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The chapter on water was expanded. In addition to more discussion of the water requirements of all classes of swine, this section also reviews factors that affect quality of drinking water. The chapter on nonnutritive feed additives was expanded to include antimicrobial agents and other feed additives, including anthelmintics, microbial supplements, oligosaccharides, enzymes, acidifiers, flavors, odor control agents, antioxidants, pellet binders, flow agents, mineral supplements, and carcass modifiers.
A new chapter that addresses nutrient excretion was added to the tenth edition. This chapter discusses the potential environmental impact of excessive excretion of nutrients, particularly nitrogen and phosphorus, and addresses means of reducing excretion of these potential environmental pollutants by dietary manipulation.
The feed ingredient composition data have been updated and greatly expanded, with 23 additional ingredients added to the tables, for a total of 79 feed ingredients. Net energy, neutral- and acid detergent fiber (NDF, ADF), and beta-carotene concentrations of feedstuffs were added, and crude fiber was deleted. Vitamin E levels in feedstuffs were modified to include only those assayed by high-performance liquid chromatography. New tables that give estimates of apparent and true digestible coefficients for the amino acids in feedstuffs are now included. Other new tables give the fatty acid composition of fat sources and estimates of the four most limiting amino acids in feedstuffs based on their crude protein content.
Finally, the tables of nutrient requirements have been revised and updated. The amino acid requirements are based on the subcommittee's assessment of the biological relationships that govern accretion of protein and fat for growth, reproduction, and lactation. The estimates for all nutrients, including amino acids, are based on the best judgment of the subcommittee members following their thorough review of the world's scientific literature.
As in previous editions, the estimated nutrient requirements in this publication are minimum standards without any safety allowances. Therefore, they should not be considered as recommended allowances. Professional nutritionists may choose to increase the levels of some of the more critical nutrients to include "margins of safety" in some circumstances (this comment does not apply to selenium). Another important point is that, for minerals and vitamins, the estimated requirements include the amounts of these nutrients that are present in the natural feedstuffs and are not estimates of amounts of nutrients that should be added to diets.
Knowledge of the nutritional needs of swine has expanded considerably since the last revision of this publication. Nevertheless, there is still conflicting, incomplete, or no information for several nutrients at different stages of the life cycle. This is particularly true for many of the vitamins and trace minerals, especially for the very young pig and the gestating and lactating sow. More research is encouraged to expand the knowledge base in these areas.
The user of this publication is reminded that knowledge of the principles and assumptions described in the text of this publication is absolutely essential for the proper use of the model and the tables of nutrient requirements.
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