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Titolo:
AN INTEGRATED, DYNAMIC-MODEL OF FEED HYDRATION AND DIGESTION, AND SUBSEQUENT BACTERIAL MASS ACCUMULATION IN THE RUMEN
Autore:
VANMILGEN J; BERGER LL; MURPHY MR;
Indirizzi:
UNIV ILLINOIS,DEPT ANIM SCI URBANA IL 61801 UNIV ILLINOIS,DEPT ANIM SCI URBANA IL 61801
Titolo Testata:
British Journal of Nutrition
fascicolo: 2, volume: 70, anno: 1993,
pagine: 471 - 483
SICI:
0007-1145(1993)70:2<471:AIDOFH>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
DIETARY ENERGY-LEVEL; NUTRIENT DIGESTION; NITROGEN; STEERS; CONTAMINATION; FORAGES;
Keywords:
MODELS; BACTERIAL ATTACHMENT; RUMEN DIGESTION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
27
Recensione:
Indirizzi per estratti:
Citazione:
J. Vanmilgen et al., "AN INTEGRATED, DYNAMIC-MODEL OF FEED HYDRATION AND DIGESTION, AND SUBSEQUENT BACTERIAL MASS ACCUMULATION IN THE RUMEN", British Journal of Nutrition, 70(2), 1993, pp. 471-483

Abstract

Hydration of feeds and bacterial attachment to feed particles are thought to play major roles in rumen digestion of fibrous feedstuffs. Theobjective of the present study was to integrate these phenomena in a mechanistic model that could be used for data analysis. The proposed model nas based on the conversion of biomass, where digestion end-products can be used for the synthesis of bacterial mass. Digestion of the potentially digestible fraction and subsequent accumulation of bacterial mass,vas based on a sequential, three-compartment model. These compartments represented substrate undergoing hydration, digestion, and bacterial mass accumulation. A fraction of the substrate was used for synthesis of bacterial mass. It was assumed that these bacteria associate either temporarily or permanently with the remaining substrate. Dacron bags containing either dry or fully-hydrated lucerne (Medicago sativa), maize (Zea mays) cobs, orchard grass (Dactylis glomerata), and wheat straw were incubated in the rumen of a steer that was infused continuously with ((NH4)-N-15)(2)SO4. The N-15-enrichments of isolated particle-associated bacteria and residue remaining in the bags were used to estimate bacterial attachment. Substrate remaining and microbial mass accumulation were analysed simultaneously. Hydration did not appearto limit digestion. Fractional rate of digestion and appearance of attached bacterial mass was fastest for lucerne. For lucerne, 5% of the digestion end-products were used for synthesis of bacteria that associated with the substrate, whereas for maize cobs, orchard grass, and wheat straw this was 16, 14, and 19% respectively. Less than 2% of digestion end-products were used for synthesis of bacteria that permanentlyremained associated with the substrate. Permanent association can occur only with the indigestible fraction, and probably represents bacterial debris. Lysis and/or detachment of bacterial cells was highest forlucerne, and was indicative of the rapid dynamics of lucerne digestion.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/11/20 alle ore 15:23:50