Effects of live weight and energy intake on nitrogen balance and total N requirements of lambs

Black, J. L.; Griffiths, David

doi:10.1079/bjn19750044

Cited by 90 publications

(62 citation statements)

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“…Furthermore, the results show that over the range of feeding levels tested (from approximately 1.8 to 4.6 times energy for maintenance; M) NR in pigs given the protein-adequate diet (Table 2) was linearly related to EI. Similar findings have been reported for rats (Miller & Payne, 1963) as well as for milk-fed calves and lambs (Blaxter & Wood, 1952;Black & Griffiths, 1975 (1976) were equivalent to only 3.0 M and 2.5 M respectively. Average daily LWG increased by 182 and 144% over the range of feeding levels tested in Expts 1 and 2 respectively.…”

Section: Discussionsupporting

confidence: 76%

“…Nitrogen retention (NR) and body composition of the growing animal are known to be influenced by the level of energy intake (EI) and dietary-protein concentration (Breirem & Homb, 1972; Black, 1974). Black & Griffiths (1975) showed that NR in milk-fed lambs given N-deficient diets was linearly related to N intake (NI) and independent of EI. Conversely, when N-adequate diets were given, NR was found to be linearly related to EI and independent of NI.…”

mentioning

confidence: 99%

“…Black & Griffiths (1975) showed that NR in milk-fed lambs given N-deficient diets was linearly related to N intake (NI) and independent of EI. Conversely, when N-adequate diets were given, NR was found to be linearly related to EI and independent of NI.…”

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confidence: 99%

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The effects of energy intake and dietary protein on nitrogen retention, growth performance, body composition and some aspects of energy metabolism of baby pigs

Campbell

Dunkin

1983

Br J Nutr

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1. The effects of level of feeding of either a protein-adequate or a protein-deficient diet on nitrogen retention (NR), growth performance, body composition and some aspects of energy utilization in pigs growing from 1.8 to 6.5 kg live weight (LW) were investigated in two experiments.2. In Expts 1 and 2 piglets were given a protein-adequate diet at four levels of intake (0.93, 1.44, 1.83 and 2.30 MJ gross energy (GE)/kg LW0'75 per d) and a protein-deficient diet at five levels of intake (1.14, 1.38, 1.68, 1.95 and 2.30 MJ GE/kg LWo 75 per d) respectively.3. For pigs given the protein-adequate diet (Expt 1) NR was linearly (P < 0,001) related to energy intake (EI) and independent of N intake (NI). NR in pigs given the protein-deficient diet (Expt 2) was linearly (P < 0.001) related to NI and independent of EL 4. Average daily LW gain responded linearly to increases in El in both experiments. However, at equivalent levels of EI pigs given the protein-adequate diet exhibited more rapid and efficient growth than those given the protein-deficient diet. The results also indicated an interaction between the effects of EI and dietary protein content for feed conversion efficiency.5. Body fat at 6.5 kg LW increased in a curvilinear fashion with increasing EI in both experiments. However, over the range of EI tested (from approximately 1.8 to 4.6 times energy for maintenance) body fat increased by 153% in Expt 1 and by only 27% in Expt 2. Pigs given the protein-deficient diet were also markedly fatter than those given the protein-adequate diet. Body protein at 6.5 kg LW decreased (P < 0.01) with increasing EI in Expt 1 but was unaffected by EI in Expt 2. 6. As estimated by multiple regression analysis, the values for the efficiency of energy utilization for protein (k,) and fat (kf) deposition were 0.76 and 0.78 respectively in Expt 1 and 0.42 and 0.89 resepctively in Expt 2. The estimates of metabolizable energy required for maintenance were 445 and 532 kJ/kg LWo 75 per d for Expts 1 and 2 respectively. Nitrogen retention (NR) and body composition of the growing animal are known to be influenced by the level of energy intake (EI) and dietary-protein concentration (Breirem & Homb, 1972; Black, 1974). Black & Griffiths (1975) showed that NR in milk-fed lambs given N-deficient diets was linearly related to N intake (NI) and independent of EI. Conversely, when N-adequate diets were given, NR was found to be linearly related to EI and independent of NI.Support for this biphasic response of NR in pigs is given by the results of Williams (1976) for pigs growing from 1.8 to 6.5 kg live weight (LW) and, for slightly heavier pigs, by the results of McCracken et al. (1980). However, because both Williams (1976) and McCracken et al. (1980) incorporated only two levels of EI in their experiments they were unable to provide information on the relationship between EI and NR for pigs given N-adequate diets.Similarly, the response of body composition to change in EI is only poorly defined. This somewhat surprising situation, which was ...

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Section: Discussionsupporting

confidence: 76%

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confidence: 99%

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The effects of energy intake and dietary protein on nitrogen retention, growth performance, body composition and some aspects of energy metabolism of baby pigs

Campbell

Dunkin

1983

Br J Nutr

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“…According to Lallo (1996), N retention showed a curvilinear response to energy intake but exhibited a linear response when increasing N levels were fed implying that N retained is more closely related to N-intake than to energy intake for goats fed diets of varying N levels. Similar response was reported with growing lambs based on the results derived from 298 nitrogen balance studies involving male cross-bred lambs from 3 to 38 kg BW (Black and Griffith 1975). In the current study, N intake was not different between treatments; although, ruminally degradable protein (RDP) was lower as the level of DDGS increased in the diets.…”

Section: Nitrogen Retentionsupporting

confidence: 63%

The effects of distillers dried grains with solubles on apparent nutrient digestibility and passage kinetics of Boer×Spanish castrated male goats

Gurung

Solaiman

Rankins

et al. 2012

Journal of Applied Animal Research

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This study was conducted to evaluate the effects of different inclusion rates of distillers dried grains with solubles (DDGS) on apparent nutrient digestibility, and passage kinetics in meat goats. Four uniform mature Boer )Spanish castrated goats (51.490.9 kg BW) were used in a 4 )4 Latin square experimental design. Animals had free-choice access to twice daily 36.5% bermudagrass hay (BGH) and 63.5% concentrates containing 0, 12.7, 25.4 and 38.1% of DDGS (dry matter [DM]basis; w/w proportion) replacing corn and soybean meal in the diet. Concentrates were isonitrogenous with 16% crude protein (CP). Each period consisted of 16 days for diets adjustment followed by 5 days of total fecal and urine collection for the digestion and passage kinetics. Concentrate and hay offered and refused, fecal and urine outputs were monitored daily. The ytterbiummarked BGH was used to determine the passage kinetics. Results indicated that with the inclusion of DDGS increased ether extract (EE) concentrations of total diets from 2.91 (0% DDGS) to 4.33% (38.1% DDGS). No differences were observed in DM and neutral detergent fibre (NDF) digestibility (P 0.05) among treatments. However, DDGS supplementation had a quadratic effect on apparent digestibilities of acid detergent fibre (ADF) and EE (P00.04). Passage kinetics and nitrogen utilisation were unaffected by DDGS inclusion (P0.05). Results of this experiment indicated that DDGS can replace up to 38.1% of diet DM for Boer )Spanish castrated goats with no adverse effects on nutrient digestion and passage kinetics.

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“…For example, Gill et al (1984) used the empirical relationship of Black & Griffiths (1975) to estimate the maximum rate of protein synthesis and the empirical equation of Graham et al (1976) to calculate maintenance energy requirements. Similarly, Pettigrew et al (1989) estimated values for maximum reaction rates and for affinity and inhibition constants from empirical data on such measures as body protein, fat depletion and milk yield of sows.…”

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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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Effects of live weight and energy intake on nitrogen balance and total N requirements of lambs

Cited by 90 publications

References 19 publications

The effects of energy intake and dietary protein on nitrogen retention, growth performance, body composition and some aspects of energy metabolism of baby pigs

The effects of energy intake and dietary protein on nitrogen retention, growth performance, body composition and some aspects of energy metabolism of baby pigs

The effects of distillers dried grains with solubles on apparent nutrient digestibility and passage kinetics of Boer×Spanish castrated male goats

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

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