Hafs / Zimbelman Low-Fat Meats

Design Strategies and Human Implications
1. Auflage 2012
ISBN: 978-0-08-091853-2
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 330 Seiten

Reihe: Food Science and Technology

This treatise embraces all of the various efforts to reduce fat in meat. Establishing methods such as breeding and feeding to control fatness are covered, but emphasis is on emerging technologies including meat processing and partitioning agents to reduce fat. Human implicaitons, such as health, social, ethical, and economic factors, are given special attention. Sensory charcteristics of low-fat meat, animal well being, and two new directions for the future are also discussed. Low-Fat Meats: Design Strategies and Human Implications provides an up-to-date overview of the technologies to produce low-fat meat, with a balanced discussion of the issues.Paying speical attention to health, social ethical, and economic implications inherent in developing low-fat meats, this volume also discusses sensory characteristics of low-fat meat, animal well being, and new directions for the future.

Autoren/Hrsg.

Hafs, Harold D.

Zimbelman, Robert G.

Inhaltsverzeichnis

1;Front Cover;1
2;Low-Fat Meats: Design Strategies and Human Implications;4
3;Copyright Page;5
4;Table of Contents;6
5;Contributors;12
6;Preface;14
7;Chapter 1. Improving Carcass Composition through Selective Breeding;18
7.1;I. Principles of Genetic Improvement;18
7.2;II. Improvement of Carcass Composition: Progress to Date;22
7.3;III. Selection on Carcass Composition: Correlated Responses;24
7.4;IV. Potential for Future Improvements in Carcass Composition;25
7.5;V. Summary;27
7.6;References;28
8;Chapter 2. Nutrition and Feeding Management to Alter Carcass Composition of Pigs and Cattle;30
8.1;I. Introduction;30
8.2;II. Impact of Energy Level;33
8.3;III. Impact of Protein Level and Protein Quality;39
8.4;IV. Relationship of Depot Fat Levels (Backfat) and Intramuscular Fat Levels;39
8.5;V. Carcass Composition as Related to Sex of Animals;42
8.6;VI. Impact of Other Nutrients and Feed Additives;43
8.7;VII. Chemical Relationships of Dietary Fat and Body Fat;44
8.8;VIII. Summary and Conclusions;45
8.9;References;47
9;Chapter 3. Human Nutrition and Health Implications of Meat with More Muscle and Less Fat;52
9.1;I. Past and Present Consumption Patterns;52
9.2;II. Nutrients from Meat;54
9.3;III. Nutritional Status as a Function of Meat Consumption;54
9.4;IV. Dietary Recommendations;55
9.5;V. Diet and Disease;56
9.6;VI. Summary and Conclusions;65
9.7;References;66
10;Chapter 4. Human Food Safety Evaluation of Repartitioning Agents;70
10.1;I. Introduction;70
10.2;II. General Human Food Safety Requirements;70
10.3;III. Human Food Safety Concerns for ß-Agonists;75
10.4;IV. Protein Hormones;78
10.5;V. Conclusion;79
10.6;References;80
11;Chapter 5. Economic Implications of Partitioning Agents;82
11.1;I. Introduction;82
11.2;II. Consumer Acceptance of Treated Meat Products;83
11.3;III. Predicting Farmers' Adoption of Partitioning Agents;86
11.4;IV. Economic Analysis of Partitioning Agent Use in Livestock Production;92
12;Chapter 6. Evaluating Lower-Fat Meats from an Ethical Perspective: Is "Good for You" Always Good for You?;104
12.1;I. Introduction: The Ethics of Agricultural Technologies;104
12.2;II. The Case for Low-Fat Meats;115
12.3;III. A Case against Low-Fat Meats?;117
12.4;IV. Conclusion: Is There an "Ethical Beef" with Low-Fat Meats?;125
12.5;References;126
13;Chapter 7. Technology to Assess Carcass and Product Composition;130
13.1;I. Introduction;130
13.2;II. On-line Assessment of Carcass Composition;131
13.3;III. Assessing Composition in the Live Animal;139
13.4;IV. The Potential Impact of Technology on the Efficient Production of Low-Fat Meat Products;142
13.5;V. Summary and Conclusions;144
13.6;References;145
14;Chapter 8. Meat Evaluation Issues and Alternatives;148
14.1;I. Introduction;148
14.2;II. Current Observations and Explanations;149
14.3;III. Current Meat Grading Practices Related to Value;150
14.4;IV. Evaluating and Marketing Livestock in the 21st Century: A Theoretical Approach;153
14.5;V. Additional Details of Evaluation Systems;156
14.6;VI. Some Final Remarks and Conclusions;157
14.7;Further Readings;159
15;Chapter 9. Strategies far Reduced-Fat Processed Meats;162
15.1;I. Introduction;162
15.2;II. Specific Strategies for Reduced-Fat Product Manufacture;164
15.3;III. Summary and Conclusions: The Cost of Adopting a Low- Fat Strategy;178
15.4;References;179
16;Chapter 10. Growth, Metabolic Modifiers, and Nutrient Considerations;184
16.1;I. Introduction;184
16.2;II. Porcine Somatotropin (PST) as a Model: Framework for Decisions Regarding the Effect of Metabolism Modifiers on Nutrient Requirements;188
16.3;III. Estimates of the Protein (Lysine) and Energy Requirements for PST-Treated Growing Swine;191
16.4;IV. ß-Adrenergic Agonists;197
16.5;V. Effect of Metabolic Modifiers on Mineral and Vitamin Requirements;201
16.6;VI. Summary;202
16.7;Refences;202
17;Chapter 11. The Welfare of Physiologically Modified Animals;208
17.1;I. Introduction;208
17.2;II. What is Animal Welfare?;209
17.3;III. Considerations for Modified Animals;210
17.4;IV. Current Evaluation of Welfare of Modified Animals;211
17.5;V. Conclusions;216
17.6;References;217
18;Chapter 12. Carcass Composition of Animals Given Partitioning Agents;220
18.1;I. Introduction;220
18.2;II. Effects of Anabolic Steroids on Growth and Carcass Composition;222
18.3;III. Effects of Somatotropin or Somatotropin Secretagogues;227
18.4;IV. ß-Adrenergic Agonists as Partitioning Agents;234
18.5;V. Summary and Conclusions;242
18.6;References;243
19;Chapter 13. Sensory Characteristics of Meat from Animals Given Partitioning Agents;250
19.1;I. Introduction;250
19.2;II. Description of the Sensory Characteristics of Meat;251
19.3;III. Review of Factors That Influence Sensory Characteristics of Meat;252
19.4;IV. Effects of Partitioning Agents on Sensory Characteristics of Meat;258
19.5;V. Summary and Conclusions;265
19.6;References;265
20;Chapter 14. Reaction of Livestock Producers to Partitioning Agents;270
20.1;I. Introduction;270
20.2;II. A Wide Range of Attitudes;271
20.3;III. Economics;274
20.4;IV. Managing Consumer Reaction;276
20.5;V. Environmental Considerations;278
20.6;VI. Producers' Responsibilities;278
20.7;VII. Summary and Conclusions;279
20.8;References;280
21;Chapter 15. An Overview of the Meat-Packing Industry and Some Perspectives on Partitioning Agents;282
21.1;I. Introduction;282
21.2;II. Structure and Characteristics of the U.S. Meat-Packing Industry;283
21.3;III. Merit Buying for Hogs;294
21.4;IV. Effect of Partitioning Agents;296
21.5;V. Purveyor's Reaction to Partitioning Agents in Hogs;298
21.6;VI. Summary and Conclusion;300
22;Chapter 16. Potential to Alter Carcass Composition through Genetically Modified Animals;302
22.1;I. Introduction;302
22.2;II. Genetic Modification to Alter Growth;306
22.3;III. State of the Art in Genetic Modification;312
22.4;IV. Issues in Genetic Modification of Animals;314
22.5;V. Summary and Conclusions;316
22.6;References;316
23;Chapter 17. Immunological Approaches to Modify Growth;320
23.1;I. Introduction;320
23.2;II. Major Influences on Animal Growth and Body Composition;321
23.3;III. Antibodies: Versatile Binding Molecules Which Can Change the Activity of Protein Hormones;322
23.4;IV. Reduction of Body Fat Using Neutralizing Antibodies Directed against Adipocytes;325
23.5;V. Enhancement of Hormone Activity: The GH Axis;326
23.6;VI. Mechanism of Action of Potentiating Antibodies;331
23.7;VII. Summary and Conclusions;334
23.8;References;334
24;Index;338

Leseproben

Chapter 2

Nutrition and Feeding Management to Alter Carcass Composition of Pigs and Cattle

Virgil W. Hays; Rodney L. Preston

I Introduction

Excess fatness in meat produced in the U.S. is largely the result of unrealistic grading standards that encourage the “over-fattening” of lambs and cattle and does not adequately discourage over-fat carcasses in swine (National Research Council, 1988a, p. 100). In addition, live animal ideals have been perpetuated which are contrary to the production of lean, efficient meat animals. As long as carcass quality grade for cattle is driven primarily by fat (marbling), dressing percent is a major determinant in pricing live meat animals, and feed grains continue to be relatively inexpensive; however, U.S. meat animals will continue to have too much fat. The first step in the “War on Fat” depends on improved methods of measuring meat quality (Preston, 1991). The incentive for altering nutrition and management to produce low fat meat will largely depend on how meat is graded and therefore the economic return to the producer, packer, and retailer. In the final analysis economic returns to the various segments of the industry depend on consumer demand for leaner meat. With the relatively low cost of feed grains and the current marketing and pricing systems that discount cattle carcasses not graded as choice and that do not greatly penalize over-fat pork carcasses, it usually is of economic advantage to feed high levels of high grain diets.

Carcasses consist of protein, fat, water, and ash. The major fraction of the ash portion is included in the bone. Though the muscle-to-bone ratio does vary some (Clawson et al., 1991), ash is the least important constituent in terms of edible meat. Normal market animals have a near constant water-to-protein ratio, approximately 3.3–3.5 to 1. This ratio is somewhat wider in young animals, but does not vary appreciably with size at maturity or among breeds and is not affected by feeding regimens. On a fat-free basis, the composition of animals (except for the very young) is rather constant. This is Moulton’s (1923) concept of chemical maturity.

Growth is a coordinated increase in protein, water, and fat, not the growth of lean and then the growth of fat. Fox and Black (1984) presented the following equations to depict the increases in water, protein, and fat with increasing empty body weight of British breed beef cattle (Figure 1),

kg=3.588+0.0671X-0.00034X2proteinkg=-2.418+0.235X-0.00013X2fatkg=-0.610+0.037X+0.00054X2,

Figure 1 Relationship between empty body weight and body composition in male castrate cattle (steers) of British beef breeds.

where X is the empty body weight of cattle. Coefficients of determination (R2) for these equations ranged from 95.6 to 98.9%. The major determinant of body composition is empty body weight; however, cattle varying in biological type (frame size which reflects mature body size) differ in weights at which they reach a given fat content. In cattle, there is a near linear increase in protein with increasing weight up to about 500 kg after which protein increases at a decreasing rate; whereas, fat increases at an increasing rate.

The introduction of exotic (large-framed) cattle has resulted in changes in body composition because of their differences in size at maturity. Animals will be of similar composition (% fat) at similar proportions of their mature body weight (Figure 2) (Preston, 1971; Owens et al., 1993). As Figures 2 and 3 (Solis et al., 1989) depict, steers will have approximately 22% carcass fat when their slaughter weight is about 68% of their mature weight (average weight of sire and dam). At 78 and 88% of mature weight, their carcasses will contain approximately 26 and 30% fat, respectively (Figure 2). To grade choice, carcasses must have about 31% fat (Fox and Black, 1984). For steers weighing 1000, 1500 or 2000 lb at maturity, their slaughter weight would need to be 880, 1320, and 1760 lb (88% of maturity), respectively, to grade choice. Thus at a given weight large-framed cattle will contain less fat than will lighter mature weight, British-type cattle.

Figure 2 Live weight, mature weight, and beef carcass composition.

Figure 3 Repartitioning fat deposition with anabolic implants in steers.

Similar body composition relationships have been reported for pigs (Reid, 1971). The grading system for pigs, however, does not include the factor of marbling (intramuscular fat). Pigs have been selected for less fat at standard market weights. This selection process has likely selected also for larger mature size, thus we are slaughtering pigs at an earlier stage of maturity.

Rate of body weight gain, efficiency of gain, and composition of the gain are genetically controlled, as discussed in Chapter 1; but, each may be influenced markedly by the balance of nutrients in the diet, the rationing of the diet, and, to a lesser extent, other factors such as effective environmental temperature, exercise, and disease. Any essential nutrient may directly or indirectly affect body composition in terms of proportions of lean (muscle), fat, and bones, primarily through its influence on rate and/or pattern of growth. Extended and marked reductions in growth rate due to nutritional deficiencies, followed by ad libitum intake of an adequate diet, may result in excess fat deposition, hence a lower ratio of lean to fat in the carcass. Extended stunting of growth by disease or adverse environmental conditions other than nutrition, again followed by conditions that allow food intake to be resumed at a high level, may have similar effects.

II Impact of Energy Level

The most common and readily demonstrated effects of nutrition on carcass characteristics relate to biologically available energy (e.g., metabolizable energy) intake relative to intake of other essential nutrients. In pigs the metabolizable energy intake, the protein (essential amino acids) intake, and protein-to-energy ratio in the diet have marked effects on carcass composition at a standardized body weight. The related effects of protein and energy are not simple. Excess protein may be utilized almost as efficiently as carbohydrates for energy purposes. This is apparent from the estimated energy values of feedstuffs (National Research Council, 1984, 1988b; Ewan, 1991) and the rates of body weight gain and fat deposition on high protein diets as reported by Wagner et al. (1963). The metabolizable energy values of the high protein ingredient soybean meal are very similar to those of the high-carbohydrate ingredient corn (3.15 vs 3.25 and 3.76 vs 3.84 Mcal/kg for cattle and pigs, respectively). The differences are somewhat greater in terms of net energy values. For beef cattle the net energy values (Mcal/kg) for gain are 1.48 and 1. 55 for soybean meal and corn, respectively; and for pigs the respective net energy values are 1.96 and 2.58.

If adequate energy in the form of carbohydrates or fat is not provided, the animal will utilize protein for energy purposes at the expense of protein accretion. These interrelationships are exemplified in pigs by studies of Cunningham et al. (1962) as summarized in Table I. The low level of feeding (1.60 kg/day) of the low protein diet was inadequate in protein or energy for maximum protein retention. At this level of feeding, protein was being used for energy purposes. Additional protein resulted in some increase in total protein deposition, but a lesser increase in protein intake in combination with increased energy intake (higher feeding level) resulted in an even greater increase in protein retention.

Table I

Effects of Diet Restriction and Protein Intake on Energy and Protein Utilization in Pigs

Trial 1

Feed intake/day (g)

1600

1600

2450

N intake/day (g)

31.2

53.1

47.8

Dig. Energy/day (cal.)

4836

4698

7311

N retention/day (g)

10.3

14.3

16.6

N retention (%)

33.0

26.9

34.4

Trial 2

Feed intake/day (g)

1630

1640

3220

Daily gain (g)

284

243

755

Feed/gain

5.82

6.95

4.40

Loin eye area (sq. in.)

4.33

4.24

4.14

Carcass protein (%)

15.2

15.6

14.6

Carcass fat (%)

38.4

37.7

40.0

Adapted from Cunningham et al. (1962).

In pigs, the effects of energy intake on performance and carcass composition may be illustrated by varying the total feed intake (restricted vs ad libitum feeding) or by varying the metabolizable energy density of the diet (by substituting fat for carbohydrate or highly digestible carbohydrates for more fibrous...