The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig

Close, W. H.; Mount, L. E.; Brown, Dorothy A.

doi:10.1079/bjn19780143

Cited by 80 publications

(66 citation statements)

References 6 publications

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“…the Agricultural Research Council (1981) estimate of 719 kJ/kg W0'63 per d converted to the slightly different exponent at the mean body-weight of these pigs). This discrepancy is to be expected as a result of the considerable rate of N retention associated with energy equilibrium in growing pigs which has been observed in our own Reeds et al 1980) and others' experiments (Close et al 1978).…”

Section: Discussionmentioning

confidence: 76%

Effects of the amount and quality of dietary protein on nitrogen metabolism and heat production in growing pigs

Fuller¹,

Cadenhead²,

Mollison³

et al. 1987

Br J Nutr

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1. Eight pigs with a mean weight of 48 kg were given, at a constant daily rate, diets of low (0.15) or high (0.30) protein content, very deficient in lysine, with or without a supplement of L-lysine (3-7 g/kg).2. Measurements of nitrogen and energy metabolism were made in four successive 14 d periods in a Latinsquare design.3. The rate of protein accretion was substantially increased by increases in both protein and lysine supply, but the rate of heat production was not significantly changed.4. The rate of fat deposition varied inversely with the rate of protein accretion, being reduced by both protein and lysine supplements.5. The relation between heat production and protein accretion (allowing for a constant energy cost of fat deposition) suggested that heat production increased with additional protein accretion less when protein quality was improved than when more protein was given.It was Kielanowski (1965) who first proposed, and who later elaborated (Kielanowski, 1966) the idea that the energy requirement of a growing animal can be considered to be the sum of three components : the energy requirements for maintenance, protein accretion (A) and fat deposition. Using multiple regression, he computed the association of metabolizable energy (ME) with A and fat deposition. The residual quantity was assumed to be the energy required for maintenance. In recent years, experiments in several species have been made to estimate the magnitude of these specific costs. As far as growing pigs are concerned, a survey of experimental evidence (Fowler et al. 1980; Agricultural Research Council, 198 1) suggested that the ME required for A is, on average, 44 kJ/g and for fat deposition 54 kJ/g. By subtracting from these values the heats of combustion of body protein and fat (23.7 and 39.6 kJ/g; Franke & Weniger, 1958) the increases in heat production associated with protein and fat deposition are 20.3 and 14.4 kJ/g respectively. These estimates are based on statistical associations, rather than physiological causation. It is simply to say that when the rate of A is increased, energy expenditure increases in constant proportion : it is not to say that there is necessarily any direct causal link between the two.By contrast, it has been estimated (Millward et al. 1976) that 4 mol ATP are required for each peptide bond formed and probably another 1 mol for additional associated energy expenditures in amino acid transport, RNA synthesis, etc. The synthesis of 5 mol ATP typically requires 400 kJ ME; assuming that the average molecular weight of amino acid residues is 116, this suggests that 3.45 kJ ME are expended for each 1 g protein synthesized.It might be thought that these estimates, 3.45 kJ/g for protein synthesis (S) and 20.3 kJ/g for A , could be reconciled if protein turnover exceeded A by a factor of 6, which indeed it commonly does (Waterlow et al. 1978). However, what is important is not the overall ratio, S: A but the marginal ratio, that is, the change in S associated with a change in A. In a previous paper (Reeds et...

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Section: Discussionmentioning

confidence: 76%

Effects of the amount and quality of dietary protein on nitrogen metabolism and heat production in growing pigs

Fuller¹,

Cadenhead²,

Mollison³

et al. 1987

Br J Nutr

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“…For example, as noted by Fowler et al (1979), the analyses of Close et al (1978) did not allow for the nitrogen retention at energy equilibrium that was evident in the data. It can be shown that this would tend to force the apparent estimates of kp and kf to be equal, as in all five sets of results in Table 3 of Close (1978), whose estimates were obtained by fitting a linear regression of RE on RE'p and RE f. Even when the regression is not forced to go through the origin, the constraint that RE -RE p + RE f can dominate the picture. As an example, in our own data a regression of RE on RE p and RE f showed some curvature.…”

Section: Discussionmentioning

confidence: 92%

A Preliminary Investigation of the Utilization of True Metabolizable Energy by Chicks

Sibbald

Morse²

1984

Poultry Science

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The change in carcass composition associated with intake of true metabolizable energy (TME) by young broiler chicks was investigated. The experiment comprised 17 treatments, 16 of which formed a 2 X 4 X 2 factorial design with six replications; the experimental unit was a pen of four male chicks. The factorial treatments consisted of two basal diets (lipogenic and proteogenic ), four levels of cellulose dilution (to cause a range of basal diet intakes), and two feeding periods (10 to 17 and 10 to 24 days of age). The birds were fed ad libitum, feed intake was recorded, and final carcass composition was measured. The 17th treatment comprised 24 pens of chicks killed at the start of the experiment to estimate initial carcass composition. The gross energy of carcass fat and protein was estimated by chemical and physical analysis and by regression analysis, the latter yielded estimates of 24.5 and 39.5 MJ/kg for protein and fat, respectively. Basal diet intake was reduced by more than 50% at the highest level of cellulose dilution and increased by about 60% when the feeding period was extended from 17 to 24 days. Pen weight gain and carcass composition were affected by basal diet intake. The energy retained in the carcass (MJ/W X 75 kg/day) (RE') increased in a linear manner with the intake of TME (MJ/W X 75 kg/day) ( ITME ), the slope of the line being greater for the lipogenic than for the proteogenic diet. Projected back to zero ITME ', the regression lines for pens in positive energy balance gave an estimate of .420 MJ loss, After 7 days on experiment, the energy retained as fat (RE'f) and as protein (RE'p) increased approximately linearly with ITME ', but after 14 days some curvature was apparent, the deposition of protein increasing more rapidly at the lower levels of energy input, and the deposition of fat increasing more rapidly at the higher levels of energy input. The RE'p was only slightly higher on the proteogenic diet than on the lipogenic diet, at the same level of ITME ', but the effect of basal diet on RE'f was considerable. For both diets at RE' = 0 there was gain in body protein accompanied by loss of body fat.

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“…When the animals are on a restricted feed intake, less feed energy is then available for growth in the cold and energy retention is reduced, most of the effect occurring in the reduction of fat deposition rather than of protein deposition (Close, Mount and Brown, 1978). Some reduction in the weight gain of growing pigs may therefore be expected when they are kept in the cold.…”

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confidence: 98%

A note on the effects of forced air movement and environmental temperature on weight gain in the pig after weaning

1980

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Twenty-six groups of four or eight pigs of mean initial weight 23-2 kg and mean age 84 days were exposed to environmental temperatures of 8, 12, 16 or 20°C under still-air conditions (wind-speed = 0-1 m.s" 1 ) or of 12 C C with wind-speeds of 0-45 or 0-8 m.s" 1 . The animals were fed at a fixed level close to three times their maintenance requirement, with water ad libitum, and were weighed weekly over a 7-week period. Variation in temperature between groups from 8 to 20°C had no significant effect on weight gain, but increasing wind-speed to 0-8 m.s" 1 at 12°C resulted in reduced weight gain.When pigs are exposed to a cold environment where the environmental temperature is below the critical level, the metabolic heat production is increased by the animal's thermoregulatory responses. When the animals are on a restricted feed intake, less feed energy is then available for growth in the cold and energy retention is reduced, most of the effect occurring in the reduction of fat deposition rather than of protein deposition (Close, Mount and Brown, 1978). Some reduction in the weight gain of growing pigs may therefore be expected when they are kept in the cold.Increasing the wind-speed at a given temperature also increases the thermal demand that is made by the environment on the animal, by leading to a rise in the convective heat loss and a rise in the critical temperature (Mount, 1978). The effects of cold have been investigated mainly in terms of changes in metabolic rate and energy balance, but it would also be useful to know to what extent weight gain is affected both by wind-speed and by environmental temperature when pigs are kept in groups under a customary husbandry regimen. The following measurements were made in an attempt to provide such information.Large White pigs of the Institute herd were weaned from the sow at 8 weeks of age, and then at about 10 weeks old sorted into groups of either four or eight animals including both females and castrated males; each group was on most occasions derived from one litter, but some groups were made up from two or three litters. Altogether, 26 groups were observed. 295

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The effects of plane of nutrition and environmental temperature on the energy metabolism of the growing pig

Cited by 80 publications

References 6 publications

Effects of the amount and quality of dietary protein on nitrogen metabolism and heat production in growing pigs

Effects of the amount and quality of dietary protein on nitrogen metabolism and heat production in growing pigs

A Preliminary Investigation of the Utilization of True Metabolizable Energy by Chicks

A note on the effects of forced air movement and environmental temperature on weight gain in the pig after weaning

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