Simulation of energy metabolism in the simple-stomached animal

Schulz, Arthur R.

doi:10.1079/bjn19780034

Cited by 36 publications

(16 citation statements)

References 18 publications

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“…Evidentemente, existe um custo energético importante, durante a deposição de proteína, de cerca de 4 mol de ATP por cada ligação peptídica e, durante a excreção de um átomo de N dos aminoácidos como ácido úrico, de 6 mol de ATP/g.átomo de N (maioria dos aminoácidos que contêm um átomo de N), podendo chegar até 18 mol de ATP nos aminoácidos que contêm três átomos de N, como a histidina (MAPES e KREBS, 1978;SCHULTZ, 1978;MACLEOD, 1997;e KLASING, 1998).…”

Section: Figure 2 -Breast Meat Weight In Function Of Increasing Me: Cunclassified

Níveis de Energia e Relações Energia: Proteína para Frangos de Corte de 22 a 42 dias de Idade

2001

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Rev. bras. zootec., 30(6):1791-1800, 2001Introdução Há cerca de 50 anos, foi reconhecido que a composição da carcaça poderia ser alterada pela manipulação nutricional da ração (FRAPS, 1943), no entanto, este princípio vem sendo pouco aplicado na formulação de rações para frangos de corte. Segundo BUYSE et al. (1998), a excessiva deposição e os problemas de saúde associados com o consumo de gordura são, atualmente, a maior preocupação de produtores, abatedores, indústrias de processamento e consumidores.Ótimas revisões têm sido publicadas listando os principais fatores que afetam a qualidade da carcaça de frangos de corte (LEENSTRA, 1986;LIN, 1980LIN, , 1981EMMANS, 1987 EMMANS, e 1995PESTI, 1999; e ALBINO et al., 2000) e a proporção caloria:proteína, pelas implicações sobre a quantidade de gordura suplementar e custo da ração, taxa de crescimento, conversão alimentar e composição corporal (PESTI, 1999), além das interações com a genética e o ambiente das aves, é, provavelmente, o fator mais importante.Segundo EMMANS (1987), em virtude das rápi-das mudanças no melhoramento genético das linhagens de frangos de corte, a realização de testes periódicos com rações variando a relação energia:proteína deve contribuir para detectar possí-veis falhas nos programas de seleção, em relação à qualidade de carcaça, e orientar eventuais correções nos planos de nutrição, a fim de evitar excesso de gordura na carcaça.Avaliando o efeito do aumento das relações EM:PB de 139 para 160 e 188, em frangos de corte de 28 a RESUMO -Níveis de energia metabolizável (EM) de 2900, 3100 e 3300 kcal e relações energia: proteína (EM: PB) de 128, 148, 168 e 188 kcal/%PB foram avaliados em frangos de corte machos de 22 a 42 dias de idade, distribuídos ao acaso em um esquema fatorial 3 x 4, com quatro repetições de 18 aves por tratamento. O aumento da relação EM: PB apresentou efeito linear decrescente sobre consumo de ração, peso vivo aos 42 dias, ganho de peso, consumo de proteína, consumo de energia metabolizável, peso da carcaça, peso da carne de peito, peso de pernas (coxa+sobrecoxa) e elevou linearmente a porcentagem de gordura abdominal na carcaça em todos os níveis de energia. A relação EM: PB de 148 (20,95% PB) dentro do nível de EM de 3100 kcal atende às exigências de ótimo crescimento de frangos de corte de 22 a 42 dias de idade, enquanto a relação EM: PB de 188 dentro de todos os níveis de energia estudados se mostrou inadequada. Em virtude do aumento do custo da ração, a redução da relação EM: PB, em rações práticas, deve ser avaliada para otimizar o modelo de produção em que a qualidade da carcaça também deve ser considerada.Palavras-chave: desempenho, gordura abdominal, peso da carcaça, frangos de corte Energy Levels and Metabolizable Energy:Protein Ratio for Male Broiler Chicks from 22 to 42 Days of AgeABSTRACT -Levels of metabolizable energy (ME) of 2,900, 3,100 and 3,300 kcal and energy to protein ratio (EM: PB) of 128, 148, 168 and 188 kcal/%CP were evaluated with male broiler chicks from 22 to 42 days of age, assigned to a ...

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Section: Figure 2 -Breast Meat Weight In Function Of Increasing Me: Cunclassified

Níveis de Energia e Relações Energia: Proteína para Frangos de Corte de 22 a 42 dias de Idade

2001

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“…The metabolic efficiency with which fats are oxidized is 98% that of glucose, proteins about 80%, alcohol about 90%, SCFAs (direct oxidation) about 85-90%. Various scholars and committees have established theoretical values of efficiency of substrate oxidation relative to glucose from the stochiometry of metabolic pathways (summarized by G Livesey) with the following ranges: protein (Blaxter, 1971(Blaxter, , 1989Schulz, 1975Schulz, , 1978Flatt, 1978Flatt, , 1980Flatt, , 1987Flatt, , 1992Livesey and Elia, 1985;Life Sciences Research Office, 1994;Black, 2000), 0.78-0.85 (mean, 0.81); fat (Armstrong, 1969;Schulz, 1975Schulz, , 1978Flatt, 1978Flatt, , 1980Flatt, , 1987Flatt, , 1992Livesey and Elia, 1985;Blaxter, 1989;Black, 2000), 0.97-1.01 (mean 0.98); fermentable carbohydrate (British Nutrition Foundation, 1990;Life Sciences Research Office, 1994;Livesey, 2002), 0.74-0.75 (mean, 0.74); and mixed short-chain organic acids (Armstrong, 1969;Livesey and Elia, 1985;Dutch Nutrition Council, 1987;Livesey, 1992;Life Sciences Research Office, 1994), 0.83-0.87 (mean, 0.85). In the case of oxidation of SCFAs by human tissues, this means that about 10-15% more heat is released for a given ATP gain than when glucose is oxidized to yield the same ATP gain.…”

Section: Net Metabolizable Energymentioning

confidence: 99%

Physiological aspects of energy metabolism and gastrointestinal effects of carbohydrates

2007

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The energy values of carbohydrates continue to be debated. This is because of the use of different energy systems, for example, combustible, digestible, metabolizable, and so on. Furthermore, ingested macronutrients may not be fully available to tissues, and the tissues themselves may not be able fully to oxidize substrates made available to them. Therefore, for certain carbohydrates, the discrepancies between combustible energy (cEI), digestible energy (DE), metabolizable energy (ME) and net metabolizable energy (NME) may be considerable. Three food energy systems are in use in food tables and for food labelling in different world regions based on selective interpretation of the digestive physiology and metabolism of food carbohydrates. This is clearly unsatisfactory and confusing to the consumer. While it has been suggested that an enormous amount of work would have to be undertaken to change the current ME system into an NME system, the additional changes may not be as great as anticipated. In experimental work, carbohydrate is high in the macronutrient hierarchy of satiation. However, studies of eating behaviour indicate that it does not unconditionally depend on the oxidation of one nutrient, and argue against the operation of a simple carbohydrate oxidation or storage model of feeding behaviour to the exclusion of other macronutrients. The site, rate and extent of carbohydrate digestion in, and absorption from the gut are key to understanding the many roles of carbohydrate, although the concept of digestibility has different meanings. Within the nutrition community, the characteristic patterns of digestion that occur in the small (upper) vs large (lower) bowel are known to impact in contrasting ways on metabolism, while in the discussion of the energy value of foods, digestibility is defined as the proportion of combustible energy that is absorbed over the entire length of the gastrointestinal tract. Carbohydrates that reach the large bowel are fermented to short-chain fatty acids. The exact amounts and types of carbohydrate that reach the caecum are unknown, but are probably between 20 and 40 g/day in countries with 'westernized' diets, whereas they may reach 50 g/day where traditional staples are largely cereal or diets are high in fruit and vegetables. Non-starch polysaccharides clearly affect bowel habit and so, to a lesser extent, does resistant starch. However, the short-chain carbohydrates, which are also found in breast milk, have little if any laxative role, although do effect the balance of the flora. This latter property has led to the term 'prebiotic', which is defined as the capacity to increase selectively the numbers of bifidobacteria and lactobacilli without growth of other genera. This now well-established physiological property has not so far led through to clear health benefits, but current studies are focused on their potential to prevent diarrhoeal illnesses, improve well-being and immunomodulation, particularly in atopic children and on increased calcium absorption.

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“…2), the stoichiometric foundation for biochemically-based simulation of energy metabolism was derived largely from Schulz (1978). But different stoichiometric coefficients were used for amino acid break down due to the differences between mammalian and avian amino acid metabolism (MacLeod, 2000).…”

Section: Energy Source and Its Predictionmentioning

confidence: 99%

“…To predict the energy value of the diet or its chemical constituents, researchers (e.g. Schulz, 1975Schulz, , 1978Livesey, 1984Livesey, , 1985MacLeod, 1994MacLeod, , 2000 have been working on modeling using the equations of the major biochemical pathways in terms of ATP generation and utilization. Livesey (1984) calculated energy yield as ATP from carbohydrates, fats and proteins which have been absorbed and are available for cellular catabolism.…”

Section: Energy Source and Its Predictionmentioning

confidence: 99%

Energy Metabolism and Protein Utilization in Chicken- A Review

Kim¹

2014

Korean Journal of Poultry Science

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Evaluation of energy in the diet is very important in animal nutrition because food intake is strongly influenced by the energy content of the diet. This means that the intake of other nutrients, such as amino acids, is affected by their ratio to energy content. Poultry can control their energy intake over a range of energy: protein ratios. Energy: protein ratio also affects the growth and body composition. Therefore we need to know what extent the relationship between energy and dietary protein influences the bird's performance. To predict the energy value of the diet or its chemical constituents, researchers have been working on modelling using the equations of the major biochemical pathways in terms of ATP generation and utilization. The activity of feeding and the metabolism caused by digestion and assimilation of food increase the animal's heat production and it can be measured by calorimetry technique. Theoretically, surplus amino acids which are not needed for protein synthesis stimulate an additional increase in metabolic rate and lead to increased energetic costs of catabolism and excretion. However, it has sometimes been shown that there was no measurable diet-induced thermoregulatory effect when an imbalanced amino acid mixture was fed. All these aspects are discussed in this review.

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Simulation of energy metabolism in the simple-stomached animal

Cited by 36 publications

References 18 publications

Níveis de Energia e Relações Energia: Proteína para Frangos de Corte de 22 a 42 dias de Idade

Níveis de Energia e Relações Energia: Proteína para Frangos de Corte de 22 a 42 dias de Idade

Physiological aspects of energy metabolism and gastrointestinal effects of carbohydrates

Energy Metabolism and Protein Utilization in Chicken- A Review

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