Degradation of starch by incubation with rumen fluid. A comparison of different starch sources

Cone, J.W.; Cliné-Theil, W.C.; Malestein, A.; Klooster, A.T. van 't

doi:10.1002/jsfa.2740490206

Cited by 61 publications

(27 citation statements)

References 13 publications

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“…Starch digestion in the rumen varies markedly among feeds (Cone et al, 1989). Maize starch is less degradable in the rumen than barley or wheat starch (Theurer, 1986), which has consequences not only for starch digestion but also for fibre digestion in the rumen, which tends to decrease with the addition of rapidly degradable starch (DePeters and Taylor, 1985).…”

Section: Discussionmentioning

confidence: 99%

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

Juniper

Browne

Bryant

et al. 2008

Animal

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Replacing grass silage with maize silage results in a fundamental change in the ratio of structural to non-structural carbohydrates with commensurate changes in rumen fermentation patterns and nutrient utilisation. This study investigated the effects of feeding four forage mixtures, namely grass silage (G); 67 g/100 g grass silage 1 33 g/100 g maize silage (GGM); 67 g/100 g maize silage 1 33/100 g grass silage (MMG); maize silage (M) to four ruminally and duodenally canulated Holstein Friesian steers. All diets were formulated to be isonitrogenous (22.4 g N/kg DM) using a concentrate mixture. Dietary dry matter (DM) and organic matter (OM) digestibility increased with ascending maize silage inclusion (P , 0.1) whereas starch and neutral detergent fibre digestibility declined (P , 0.05). Ratio of non-glucogenic to glucogenic precursors in the rumen fluid increased with maize silage inclusion (P , 0.01) with a commensurate reduction in rumen pH (P , 0.05). Mean circulating concentrations of insulin were greatest and similar in diets MMG and GGM, lower in diet M and lowest in diet G (P , 0.01). There were no effects of diet on the mean circulating concentration of growth hormone (GH), or the frequency, amplitude and duration of GH pulses, or the mean circulating concentrations of IGF-1. Increasing levels of DM, OM and starch intakes with the substitution of grass silage with maize silage affected overall digestion, nutrient partitioning and subsequent circulating concentrations of insulin.

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Section: Discussionmentioning

confidence: 99%

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

Juniper

Browne

Bryant

et al. 2008

Animal

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“…Recently, Malestein et al (1988) showed clear differences in starch degradation upon incubation with rumen fluid or cr-amylase. Cone et al (1989) showed a constant order in degree of digestibility of different starches upon incubation with rumen fluid from cows fed on three different rations. It was not possible to accurately predict the rate of starch degradation by rumen fluid with enzymic degradation (Cone and Vlot 1990).…”

Section: Introductionmentioning

confidence: 99%

Degradation of starch in feed concentrates by enzymes, rumen fluid and rumen enzymes

Cone

1991

J Sci Food Agric

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A B S T R A C TThe degradation of starch from various feedstujji was investigated with rumen fluid, a-amylase, pancreutin and a freeze-dried, cell-free preparation of rumen fluid. Rumen fluid was taken from either a hay-fed cow or a concentrate-fed cow. I t was shown that incubations with rumen fluid at a constant p H of 6.5 gave a higher degradation of starch than those with a decreasing p H . The degree of starch degradation varied widely for the 21 feedstufs investigated. Sorghum, maize and millet degraded slowly whereas tapioca showed fast degradation. Processed ,feedstujJs showed a higher level of degradation than unprocessed ones. The use of enzymes did not allow an accurate prediction of starch degradation by rumen fluid. However, this was made possible by the use of a ,fLeeze-dried, cell-Jiee preparation of rumen fluid. Scanning electron microscopic observations showed that for the degradation of starch granules additional enzymes, present in rumen ,fluid, are necessary.

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“…In vitro estimates of starch degradation rate relating to the small intestine have proved to be unreliable during a previous modelling attempt (Ewing and Johnson, 1987). Data is available relating to incubations with the appropriate enzymes such as those found in pancreatin (Cone et al, 1989;Cone, 1991) or intestinal mucosa extractions (Coombe and Siddons, 1973). However, problems arise when these values are applied to starch degradation as it occurs in the small intestine.…”

Section: In Vitro Determination Of Small Intestinal Starch Degradationmentioning

confidence: 99%

A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 2. Postruminal starch digestion and small intestinal glucose absorption

Mills¹,

France²,

Dijkstra³

1999

J. Anim. Feed Sci.

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The objective of this paper is to review the literature concerning postruminal starch digestion and glucose absorption in the lactating dairy cow and to propose the framework for a mechanistic model representing these processes. Postruminal starch digestion is of particular importance where high levels of rumen escape starch flow from the rumen. However, the digestion of starch and absorption of the resulting glucose within the small intestine may be limited by pancreatic secretion of oc-amylase and the distribution of SGLT1 glucose transporters respectively. During the investigation, use is made of data gathered from both in vivo and in vitro studies concerning mainly lactating dairy cows. The relative importance of ruminal and postruminal starch digestion is discussed along with the significance of dietary starch source and processing method as factors affecting postruminal starch digestion. Postruminal starch digestion and intestinal glucose uptake becomes increasingly important at high starch intakes. Other factors influencing the nature of starch digestion are also presented in order to allow the interpretation of experimental data and hence the development of a conceptual model of starch digestion. The review subsequently examines postruminal starch digestion as it is represented in extant models of ruminant digestion and discusses the essential elements of a digestion model that would have the required capability to accurately account for the fate of rumen escape starch in a range of practical feeding situations. Whilst the digestion of starch within the rumen is well represented in several working models presented in the literature, postruminal starch digestion and glucose uptake has been largely ignored. Finally, a proposed framework is presented as a scheme upon which a future model of starch digestion in the dairy cow may be built. INTRODUCTIONCurrent methods of feed evaluation for dairy cows are too imprecise to meet the demands of today's dairy farmer. There is a requirement for increased production efficiency in order to maintain financial margins at lower product prices. High genetic merit cows are capable of high milk yields, however the performance of these cows varies widely depending on nutritional inputs. In particular, the trend towards maximising the energy density of diets and hence the feeding of high starch feedstuffs has highlighted the variation in milk production between apparently isoenergetic diets. Both dietary starch concentration and starch type affects the milk yield and composition. There has also been debate as to the merit of rumen escape starch and the potential energetic benefits that may exist where glucose is absorbed directly from the small intestine, avoiding rumen fermentation and associated heat energy losses. The prospect of influencing plasma glucose concentrations via the small intestinal digestion of starch and uptake of the glucose from the intestinal lumen has implications for mammary glucose supply and therefore milk yield. Employing dynamic mechanisti...

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Degradation of starch by incubation with rumen fluid. A comparison of different starch sources

Abstract: The degradability of starch fiom various feedstuffs was investigated in vitro

Cited by 61 publications

References 13 publications

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

Digestion, rumen fermentation and circulating concentrations of insulin, growth hormone and IGF-1 in steers fed diets based on different proportions of maize silage and grass silage

Degradation of starch in feed concentrates by enzymes, rumen fluid and rumen enzymes

A review of starch digestion in the lactating dairy cow and proposals for a mechanistic model: 2. Postruminal starch digestion and small intestinal glucose absorption

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