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 | Acesso ao texto completo restrito à biblioteca da Embrapa Caprinos e Ovinos. Para informações adicionais entre em contato com cnpc.biblioteca@embrapa.br. |
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Registro Completo |
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Biblioteca(s): |
Embrapa Caprinos e Ovinos. |
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Data corrente: |
01/08/1992 |
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Data da última atualização: |
03/05/2023 |
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Autoria: |
BRODERICK, G. A. |
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Afiliação: |
GLEN A. BRODERICK. |
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Título: |
In vitro procedures for estimating rates of ruminal protein degradation and proportions of protein escaping the rumen undegraded. |
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Ano de publicação: |
1978 |
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Fonte/Imprenta: |
The Journal of Nutrition, v. 108, n. 2, p. 181-191, Feb., 1978. |
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DOI: |
10.1093/jn/108.2.181 |
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Idioma: |
Inglês |
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Conteúdo: |
Abstract: An in vitro procedure, in which rates of ruminai protein degradation and proportions of protein escaping ruminai degradation were estimated from release of amino acid plus ammonia in the presence of hydrazine sulfate ( HS ), was developed and applied to casein. An equation was derived to estimate proportion of protein escaping ruminai degrada tion: estimated % escape = (kr/(kr + kd)) X 100, where kr and k~a are fractional rate constants for ruminai protein turnover (washout) and degradation, respectively. HS, when added at 1.0 mM to an incubation medium consisting of strained ruminai liquor (SRL) and McDougall's buffer, was found to effectively inhibit removal of added amino acids and ammonia. Thus, protein degradation may be estimated from accumulation of these end-products. Casein was incubated in the medium in small quantities (2 mg/ml SRL) and its degradation estimated by this procedure. Casein degradation was found to be a first-order process, with plots of log fraction undegraded versus time being linear up to 3 hours, and with mean kd = 0.242/hour. Assuming kr = 0.04/hour, a value of 14.2^0 ( (0.04/(0.04 + 0.242)) X 100) ruminai escape was calculated. Alkali-labile phosphorus (ALP) naturally bound to casein was used in an alternative approach to quantitate casein disappearance. In vitro studies indicated 1.0 HIM HS did not inhibit casein degradation (measured by ALP disappearance) up to 3 hours, and both the amino acid plus ammonia release and ALP pro cedures gave comparable results. Casein kd value determined simultane ously in vivo and in vitro were, respectively, 0.462/hour (by ALP) and 0.300/hour (by amino acid plus ammonia release). Use of cetyltrimethyl- ammonium bromide when stopping incubations increased apparent amino acid plus ammonia release rates, presumably by rupturing microbial cell walls. Alternative kd measurement was made from the ratio of Michaelis- Menten kinetic constants, k'd = Vâ??,ax/Km. Results suggest that this approach may give more accurate kd estimates. Implications of the described theory and techniques are also discussed. J. Nutr. 108: 181-190, 1978. MenosAbstract: An in vitro procedure, in which rates of ruminai protein degradation and proportions of protein escaping ruminai degradation were estimated from release of amino acid plus ammonia in the presence of hydrazine sulfate ( HS ), was developed and applied to casein. An equation was derived to estimate proportion of protein escaping ruminai degrada tion: estimated % escape = (kr/(kr + kd)) X 100, where kr and k~a are fractional rate constants for ruminai protein turnover (washout) and degradation, respectively. HS, when added at 1.0 mM to an incubation medium consisting of strained ruminai liquor (SRL) and McDougall's buffer, was found to effectively inhibit removal of added amino acids and ammonia. Thus, protein degradation may be estimated from accumulation of these end-products. Casein was incubated in the medium in small quantities (2 mg/ml SRL) and its degradation estimated by this procedure. Casein degradation was found to be a first-order process, with plots of log fraction undegraded versus time being linear up to 3 hours, and with mean kd = 0.242/hour. Assuming kr = 0.04/hour, a value of 14.2^0 ( (0.04/(0.04 + 0.242)) X 100) ruminai escape was calculated. Alkali-labile phosphorus (ALP) naturally bound to casein was used in an alternative approach to quantitate casein disappearance. In vitro studies indicated 1.0 HIM HS did not inhibit casein degradation (measured by ALP disappearance) up to 3 hours, and both the amino acid plus ammonia release and ALP pro cedure... Mostrar Tudo |
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Palavras-Chave: |
Dietary proteins; Nutricao proteica; Ruminal in vitro incubation; Ruminal protein degradation; Ruminal protein escape; Ruminal turnover. |
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Thesagro: |
Ruminante. |
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Thesaurus Nal: |
Amino acids; Casein; Cattle; Hydrazines; Hydroxylamine; Kinetics; Physiology; Rumen fermentation. |
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Categoria do assunto: |
-- |
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Marc: |
LEADER 03090naa a2200313 a 4500
001 1520233
005 2023-05-03
008 1978 bl uuuu u00u1 u #d
024 7 $a10.1093/jn/108.2.181$2DOI
100 1 $aBRODERICK, G. A.
245 $aIn vitro procedures for estimating rates of ruminal protein degradation and proportions of protein escaping the rumen undegraded.$h[electronic resource]
260 $c1978
520 $aAbstract: An in vitro procedure, in which rates of ruminai protein degradation and proportions of protein escaping ruminai degradation were estimated from release of amino acid plus ammonia in the presence of hydrazine sulfate ( HS ), was developed and applied to casein. An equation was derived to estimate proportion of protein escaping ruminai degrada tion: estimated % escape = (kr/(kr + kd)) X 100, where kr and k~a are fractional rate constants for ruminai protein turnover (washout) and degradation, respectively. HS, when added at 1.0 mM to an incubation medium consisting of strained ruminai liquor (SRL) and McDougall's buffer, was found to effectively inhibit removal of added amino acids and ammonia. Thus, protein degradation may be estimated from accumulation of these end-products. Casein was incubated in the medium in small quantities (2 mg/ml SRL) and its degradation estimated by this procedure. Casein degradation was found to be a first-order process, with plots of log fraction undegraded versus time being linear up to 3 hours, and with mean kd = 0.242/hour. Assuming kr = 0.04/hour, a value of 14.2^0 ( (0.04/(0.04 + 0.242)) X 100) ruminai escape was calculated. Alkali-labile phosphorus (ALP) naturally bound to casein was used in an alternative approach to quantitate casein disappearance. In vitro studies indicated 1.0 HIM HS did not inhibit casein degradation (measured by ALP disappearance) up to 3 hours, and both the amino acid plus ammonia release and ALP pro cedures gave comparable results. Casein kd value determined simultane ously in vivo and in vitro were, respectively, 0.462/hour (by ALP) and 0.300/hour (by amino acid plus ammonia release). Use of cetyltrimethyl- ammonium bromide when stopping incubations increased apparent amino acid plus ammonia release rates, presumably by rupturing microbial cell walls. Alternative kd measurement was made from the ratio of Michaelis- Menten kinetic constants, k'd = Vâ??,ax/Km. Results suggest that this approach may give more accurate kd estimates. Implications of the described theory and techniques are also discussed. J. Nutr. 108: 181-190, 1978.
650 $aAmino acids
650 $aCasein
650 $aCattle
650 $aHydrazines
650 $aHydroxylamine
650 $aKinetics
650 $aPhysiology
650 $aRumen fermentation
650 $aRuminante
653 $aDietary proteins
653 $aNutricao proteica
653 $aRuminal in vitro incubation
653 $aRuminal protein degradation
653 $aRuminal protein escape
653 $aRuminal turnover
773 $tThe Journal of Nutrition$gv. 108, n. 2, p. 181-191, Feb., 1978.
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Embrapa Caprinos e Ovinos (CNPC) |
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| 1. |  | PORFÍRIO, K. de P.; RÊGO, W. M. F. do; SANTOS, R. L. do; CLEMENTINO, D. C.; LIMA, D. de S.; ALVES, F. S. F.; PINHEIRO, R. R.; DINIZ, B. L. M.; CARDOSO, J. de F. S.; PAULA, N. R. de O. Perfil sanitário de rebanhos ovinos e caprinos da Microrregião do Alto Médio Gurguéia, no Sul do estado do Piauí, Brasil. In: CONGRESSO BRASILEIRO DE MEDICINA VETERINÁRIA, 38., 2011, Florianópolis. Anais... Florianópolis: SBMV, 2011. 3 f. 1 CD-ROM.| Tipo: Artigo em Anais de Congresso |
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