Energy and protein nutrition of early-weaned pigs. 2. effect of energy intake and energy: protein on energy utilisation and body composition of pigs slaughtered at 32 d

McCracken, K. J.; Eddie, S. M.; Stevenson, W. G.

doi:10.1079/bjn19800093

Cited by 22 publications

(3 citation statements)

References 14 publications

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“…1972;Miiller, Kirchgessner and Kellner, 1974;Braude, Keal and Newport, 1977;McCracken, Eddie and Stevenson, 1980), it is interesting to observe that only in the investigations of Braude et al (1977) did the fat content of one of their groups of experimental piglets approach that of the suckled piglets in the present experiments. 1972;Miiller, Kirchgessner and Kellner, 1974;Braude, Keal and Newport, 1977;McCracken, Eddie and Stevenson, 1980), it is interesting to observe that only in the investigations of Braude et al (1977) did the fat content of one of their groups of experimental piglets approach that of the suckled piglets in the present experiments.…”

Section: Discussionmentioning

confidence: 47%

Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 1. Growth and body composition

Stanier

1984

Anim. Sci.

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1. Eighteen litters of piglets were weaned at 14 days of age and reared for a further 3 weeks at environmental temperatures of 18, 23 or 28°C. At each environmental temperature three levels of feeding were used. The changes in body composition of the piglets were studied by the comparative slaughter procedure, littermates being analysed at birth, and at 14, 22 and 36 days of age. For comparison, the bodies of suckled piglets of similar weights and ages were also analysed.2. In the 2 to 3 day period following weaning, body weight decreased, with the greatest reduction being 0·28 (s.e. 002) kg at 18°C. Following this, body weight gain was dependent on both environmental temperature and level of feeding, although at any given level of food intake there was little difference between the values at 23 or 28°C.3. There were marked changes in the chemical composition of the carcass in relation to the different temperature/feeding level combinations. The most variable component was fat. In the period following weaning there was considerable mobilization of fat, especially at the lower temperatures and feeding levels. The fat content of the early weaned piglets at 36 days of age (68 to 103 g/kg) was significantly less than that of the suckled piglets (169 g/kg) (P < 0·01). The decreases in fat content were accompanied by increases in the dry-matter content of the carcass.4. The protein content of the carcass remained relatively independent of the different treatments, ranging from 140 to 164 g/kg for the early-weaned piglets, compared with 139 g/kg for those that had suckled their mothers.5. The differences in the growth and body composition of the early-weaned piglet are discussed in relation to an inadequate food intake following weaning, to changes in nutrient supply and to variations in the climatic environment.

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Section: Discussionmentioning

confidence: 47%

Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 1. Growth and body composition

Stanier

1984

Anim. Sci.

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“…Many other authors us e 0.75 as an adopted convention , even though their data may show another value to be more 'accurate ', e.g. Jordan and Brown (1970) , Th orbek and Henkel (1976) , Carr, Boorman and Co le (1977 , Holmes and Close (1977) , Close et al , (1978) , Mc Cracken et al (1980 and Holmes et al (1979) .…”

Section: Th E Relationship Between Liveweigh T and Variousmentioning

confidence: 99%

The energy and nitrogen metabolism and performance of pigs infected with Oesophagostomum dentatum

Stewart¹,

Holmes²,

Smith³

et al. 1983

Anim. Sci.

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The effect of Oesophagostomum dentatum on the performance of growing pigs over the live-weight range 20 to 80 kg was investigated. Fourteen individually-penned pigs in Experiment 1 and 16 group-penned but individually fed pigs in Experiment 2 were orally dosed once with 80 000 or 20 000 larvae respectively at about 18 kg live weight. Worm-free but otherwise similar pigs served as controls. Three energy and nitrogen balance studies were undertaken in two open-circuit calorimeters on four infected gilts and their paired worm-free counterparts on two levels of feeding at 7, 21 and 49 days after infection. Worm burdens averaging 4 255 and 4 722 in Experiments 1 and 2 respectively were recorded post mortem but performance and carcass measurements were not affected, neither were there any clinical symptoms. No significant differences between infected and worm-free pigs were recorded for either apparent digestibility of nitrogen and gross energy or for nitrogen retention. Possible reasons for the lack of measurable effects on pig performance are discussed.

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“…The problem is greatest with classical separation techniques and is exacerbated by increases in dietary protein content. With pigs, N balance usually overestimates retention relative to slaughter data by 1620% (McCracken et al 1980;Just et al 1982) and many studies in the literature on animals from rats to cattle are subject to much larger errors. It is almost certainly the case that there is a small systematic underestimation of N retention by the slaughter method, but it is equally certain that the more serious errors lie in the balance data due both to overestimation of intake and underestimation of excretion.…”

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confidence: 99%

Merits of empirical and mechanistic approaches to the study of the energy metabolism

McCracken¹

1992

Proc. Nutr. Soc.

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The title implies a clear separation of two approaches to the understanding of energy metabolism, which seldom, if ever, applies. Those empirical relationships which have stood the test of time were based on the concept of some uniformity of physiological function arising from an underlying and universal mechanism. Conversely the most sophisticated computer simulations of energy metabolism from cellular kinetics ultimately depend on empirical relationships which can be validated only by accurate measurements of whole-body energy expenditure.However, there are marked differences of philosophy and of purpose between empirical and mechanistic approaches. These were succinctly described by Baldwin & Miller (1989), and the author can do no better than to paraphrase two paragraphs of their comments.'The term empirical is appropriate to describe models/equations wherein data obtained in input:output animal experiments were used to parameterize equations. In a strict sense the only restriction imposed on defining empirical equations is that the equations should best describe relationships among two or more variables, i.e. the equations need not imply anything about underlying/metabolic relationships. Many models based on empirical relationships have been developed and have been useful when applied carefully and with appropriate recognition of the limitation that such equations only apply within the range and conditions of the collected data used to parameterize the model.Mechanistic models/equations, by definition are based on our understanding of underlying cause-and-effect relationships and should apply to a wide range of conditions. The use of the term mechanistic implies that our knowledge of the system is complete and, further, that sufficient biochemical, physiological and metabolic data are available to parameterize all the mechanistic equations in the model. This is rarely, if ever, the case. ' The main purpose of empirical relationships in the field of energy metabolism, as in other aspects of biological science, has been to identify and quantify the degree of uniformity of biological function within and between species. The secondary purpose has been to apply these relationships in order to determine energy requirements for different species in relation to specific physiological status, and this has been the cornerstone of development of feeding systems for animal production and of recommended dietary intakes for humans. Most notable among the empirical relationships are those relating to the allometry of growth and organ development, the surface area law and the inter-specific relationship between basal metabolism and metabolic body size. During the 1970s the increased availability of personal computers, coupled with the vast data pools which had been accumulated during the previous 20 years, gave an impetus to the development of complex factorial models such as the Edinburgh pig model (Whittemore available at https://www.cambridge.org/core/terms. https://doi

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Energy and protein nutrition of early-weaned pigs. 2. effect of energy intake and energy: protein on energy utilisation and body composition of pigs slaughtered at 32 d

Cited by 22 publications

References 14 publications

Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 1. Growth and body composition

Effects of plane of nutrition and environmental temperature on the growth and development of the early-weaned piglet 1. Growth and body composition

The energy and nitrogen metabolism and performance of pigs infected with Oesophagostomum dentatum

Merits of empirical and mechanistic approaches to the study of the energy metabolism

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