Processing cereal grains for cattle — a review

Campling, R. C.

doi:10.1016/0301-6226(91)90144-f

Cited by 39 publications

(19 citation statements)

References 44 publications

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“…Although the inhibition of amylases represents an alternative approach to those procedures aimed at reducing ruminal starch digestion by a previous physical or chemical modification of the substrate,3, 11, 39, 40 results obtained in the present work show that, owing to the diversity of amylases present in the ruminal ecosystem, a complete and specific inhibition seems to be quite unlikely. Nevertheless, in recent years there has been considerable interest in the use of trace minerals in ruminant diets, this being stimulated by reports indicating improved performances,28, 29 but the mode of action of trace minerals such as Zn 2+ is virtually unknown 41.…”

Section: Discussionmentioning

confidence: 55%

Inhibition of amylases present in ruminal particle‐associated micro‐organisms

2002

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The effect of different substances potentially inhibitory of ruminal amylase activity in sheep was assessed using biochemical and electrophoretic assays. Most amylase activity was detected in the particle-associated fraction (70%) of the ruminal contents (which was selected for the assays) in comparison with the bacterial (21%) and extracellular (9%) fractions. Salts of divalent ions such as Sn 2 , Hg 2 , Cu 2 and Zn 2 produced 90, 82, 65 and 44% inhibition of amylase activity respectively when assayed at a relative concentration of 5 Â 10 À3 mol l À1 . Organic acids such as tannic, formic, ascorbic and benzoic acid produced 79, 48, 43 and 37% inhibition respectively, whereas chelators such as EDTA, EGTA and 1,10-phenanthroline produced an inhibition ranging from 32 to 37%. Substrate SDS-PAGE zymograms allowed the identi®cation of different amylase-active bands in ruminal extracts, showing a wide range of relative molecular masses (from 36 to more than 100 kDa). Such zymograms also con®rmed the effect of some inhibitors. The reversibility of the inhibitory effect of some of the assayed substances was assessed. ZnSO 4 was the most persistent inhibitory substance even at low concentrations and, owing to its low toxicity, appears to be an adequate substance to reduce the high in vitro ruminal degradation of starch. Implications for the process of enzymatic digestion of starch are discussed.

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Section: Discussionmentioning

confidence: 55%

Inhibition of amylases present in ruminal particle‐associated micro‐organisms

2002

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“…It is accepted that changing the site of digestion of starch from the rumen to the intestine leads to a more efficient utilization of the energy in cereals 6, 21. Different physical and chemical modifications of grains have being used in order to manipulate the hydrolysis of starch in the gastrointestinal tract of ruminants,1, 2, 22, 23 but none have focussed on the possible use of tannins for this purpose.…”

Section: Discussionmentioning

confidence: 99%

Effects of tannic acid and quebracho tannins on in vitro ruminal fermentation of wheat and corn grain

et al. 2006

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Current understanding of the effect of moderate amounts of tannins on the utilization of protein contained in forages indicates beneficial effects when fed to ruminants. Nevertheless, there is little knowledge about the effects of tannins on the ruminal hydrolysis of starch-rich concentrates. Modulation of the hydrolysis of starch may reduce the occurrence of metabolic disorders, such as acidosis, in ruminants consuming high-grain diets. The effects of commercial tannic acid (hydrolysable tannins) and quebracho tannins (condensed tannins) (50 g kg −1 DM) on the in vitro fermentation of ground wheat and corn grains by mixed ruminal bacteria was examined. The architecture and chemical composition of wheat and corn endosperms might explain differences in fermentation rates, as well as in response to similar concentrations of tannins. Regardless of the source of tannin, microbial fermentation was inhibited in both grains, as demonstrated by a decline in gas production, DM disappearance, volatile fatty acids and ammonia production. However, these effects were more pronounced for wheat than corn grain, mostly during the initial stages of the incubation. Scanning electron microscopy revealed that both sources of tannins inhibited the microbial hydrolysis of the endosperm protein matrix. Tannins did not prevent bacterial attachment to starch granules, but starch hydrolysis was slowed indirectly as a result of a tannin-mediated reduction in the degradation of the surrounding protein matrix. Tannins are likely to be more effective at modulating the rate of starch digestion in grains that possess a readily degradable protein matrix.

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“…Dairy cows fed oat based diets had improved organic matter digestibility and higher milk yield and milk fat percentage compared with cows fed wheat or barley based diets (Moran 1986). Several studies have also shown that little or no processing is needed when oats are fed to ruminants (Morgan and Campling 1978 ;Campling 1991). Data on ruminal degradability and feeding value of oats for beef cattle are limited, although studies have shown oat starch to be more degradable than corn and sorghum starches and less degradable than that from barley and wheat 1986 ; Herrera-Saldana et al (^rskov 1988).…”

Section: Introductionmentioning

confidence: 95%