Fat Content and Composition of Animal Products Proceedings of a Symposium (1976) / Chapter Skim
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Nutrition and Management Aspects of Nonruminant Animals Related to Reduction of Fat Content in Meat
Nutrition and Management Aspects of Nonruminant Animals Related to Reduction of Fat Content in Meat
Pages 116-142
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From page 116... ...
Studies, usually designed for other purposes, also have shown that the body composition of broiler chickens, ducks, and turkeys may be modified. Some of the factors studied that may affect the body-fat content of nonruminant animals include genetic stock, age and weight marketed, sex, exercise, ambient temperature, and diet.
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From page 117... ...
Their data suggest that only small changes in carcass fat can be achieved without adversely affecting growth rate. As growth proceeds in pigs beyond a certain weight, the impetus to deposit fat appears to exceed that for protein, and body fat increases in a curvilinear manner.
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From page 118... ...
As in the pig, body fat varies inversely with body water. Although considerable deviation in body-fat content as a function of body weight has been achieved in poultry, a prediction equation, based on age, has been developed (Combs, 1968)
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From page 119... ...
Higher protein levels (20%, 17%, and 14%) resulted in more lean cuts, and the dif
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From page 120... ...
, who found that increasing the ambient temperature from 75° to 90° F significantly increased body fat in broilers fed diets containing added fat and that reducing the temperature from 75° to 55° F reduced carcass fat content.
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From page 121... ...
When fat is added in place of a cereal component without adjustment in protein level, the energy: protein ratio widens and the broiler consumes relatively more energy and deposits more body fat. This is illustrated by the results obtained by Edwards et al.
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From page 122... ...
Nevertheless, the dietary factors that have the greatest effect on energy intake, and thus carcass composition, are energy concentration of the diet, protein level of the diet, and, especially, the ratio of energy to protein. EN ERGY : P ROT EI N RAT IO Chickens Fraps (1943)
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From page 123... ...
(1959) obtained marked differences in body-fat content of White Pekin ducks by alterations in the energy: protein ratio of the diet, thus providing further support for the belief that the ratio of energy to protein is more important than either the energy or protein level per se in determining feed intake and body fat (Donaldson et al., 1956~.
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From page 124... ...
involving the inclusion of 3%, 10.5%, or 18% corn oil in the diet to TABLE 5 Effect of Varying Protein Level on Fat Content of Pekin Ducks a Dietary Protein (% ) ME: Protein Ratio b Carcass Fat ( % )
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From page 125... ...
ENERGY INTAKE AND NITROGEN RETENTION Most of the studies with poultry that show highly significant relationships between the energy: protein ratio and body-fat content have dealt primarily with normal to low protein levels. When the protein level is reduced below that required for a given energy level, chickens increase their voluntary energy consumption and deposit more body fat.
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From page 126... ...
To summarize: As the protein level is lowered, energy content is increased or the energy: protein ratio is widened, carcass fat content is increased, and the percentage of dietary nitrogen and dietary energy retained in the carcass is increased. AMINO ACID DEFICIENCY The effect of a specific amino acid deficiency on voluntary appetite and body composition is different from that of a low-protein diet (or a wide energy: protein ratio)
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From page 127... ...
. Overconsumption of energy and increases in the carcass fat have been observed with pigs fed cottonseed meal and sunflower meal due to TABLE 7 Effect of Dietary Energy and Protein Level on Nitrogen Retention in Chicks a Dietary Protein (% )
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From page 128... ...
Brobeck (1948) pointed out the intimate correlation between body temperature and food intake and suggested that heat acts on the sensitive neurons of the rostral hypothalmus and the preoptic area of the brain or directly upon neurons of the "appetite center." HIGH PROTEIN LEVELS In view of the effect of protein level per se on voluntary energy intake and body composition as described above, a series of studies was conducted at the University of Maryland with growing broilers to determine whether increasing the protein above that needed for optimal growth would further reduce the feed required per unit of gain and body-fat content (Combs, 19651.
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From page 129... ...
ENERGY AND PROTEIN LEVELS ( PIGS ) Dietary energy and protein levels have been varied in a large number of studies as a means of influencing energy intake and fattening in pigs.
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From page 130... ...
, showing that the carcass composition of the pig changes considerably as it grows heavier and older, efforts have been made to influence the relative bodyfat content by nutritional means. Early nutrition may affect body composition at weaning, but it is likely to have little effect on body-fat content at market weight.
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From page 131... ...
It is likely that the principles of nutritional management that apply to poultry also apply to pigs, but most of the genetic types of pigs used in the United States for meat production are likely to deposit large amounts of fat in their carcasses unless energy intake is restricted. Genetic types that will respond to differences in diets (higher protein level)
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From page 132... ...
Several workers have obtained little effect from higher protein levels (12%-18% ~ on carcass fat: lean ratios (Hudman and Peo, 1960; Clawson, et al., 1962; Meade et al., 1966; Newell and Bowland, 1972~. Others have reported significant increases in muscle deposition from feeding more protein (Robinson and Lewis, 1964; Holme et al., 1965; Lee et al., 1967~.
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From page 133... ...
reported that when the same low-energy diet was fed to pigs permitted to self-feed, they were able to eat more total feed and showed less difference in performance. How restriction of corn-base finishing diets affect carcass composition has been studied by Greer et al.
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From page 134... ...
Since feed restriction almost always results in less total gain in body weight as carcass fat is reduced, it is clear that improved methods of marketing are needed that will place more value on proportion of lean cuts and less on total weight. Accordingly, Lind and Berg (1973)
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From page 135... ...
found that pigs fed a single meal daily deposited less body fat than pigs fed the same amount of feed over five meals (Table 14~. These results suggest that a hyperlipogenic state can be produced in the pig by restricting the feeding time.
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From page 136... ...
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From page 137... ...
This includes vitamins and minerals, as well as essential amino acids. Marginally low levels of the first limiting amino acid or mineral should be avoided because suboptimal or marginally deficient levels of certain of these may cause a relative overconsumption of dietary energy and increased deposition of body fat.
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From page 138... ...
may not be increased. Accordingly, low protein levels should be avoided, and higher levels of dietary protein during the finishing period can be expected to minimize the carcass-fat content in relation to the genetic potential of the animal.
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From page 139... ...
1965. Pages 88-99 in Amino Acid and Protein Level on Feed Intake and Body Composition, 1965 Maryland Nutrition Conference for Feed Manufacturers, March 18-19, 1965.
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From page 140... ...
1967. Dietary protein level and swine carcass traits.
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From page 141... ...
1968. Pages 18-37 in Changes in Body Composition and Meat Characteristics Accompanying Growth of Animals, 1968 Cornell Nutrition Conference for Feed Manufacturers.
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From page 142... ...
1969. Effects of starter protein level on performance and body composition of pigs.
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