The effect of processing on digestion and utilization of cereals by ruminants

Ørskov, E. R.

doi:10.1079/pns19760038

Cited by 50 publications

(16 citation statements)

References 26 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: 63%

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: 63%

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

2002

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“…As a result, liver abscesses and digestive disturbances are comnlon in ruminants fed high-barley diets (Chihaya et al 1988). Unprocessed barley is inefficiently utilized by cattle, and some form of physical processing is required to facilitate its.digestion by cattle (Nicholson et al 1971;@rskov 1976 (Hyslop et al 1989;McAllister et al 1990b). …”

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confidence: 99%

Effect of formaldehyde-treated barley or escape protein on nutrient digestibility, growth and carcass traits of feedlot lambs

McAllister¹,

Beauchemin²,

McClelland³

et al. 1992

Can. J. Anim. Sci.

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“…Increase of ruminally degradable starch improves the proportion of urea recycled to the gastrointestinal tract by enhancing microbial utilization of ruminal NH 3 [4]. On the other hand, starch digestion in the rumen influences accumulation of volatile fatty acids and total acids, pH, microbial ecology, and has negative impacts on fibre digestion [5–7]. …”

Section: Introductionmentioning

confidence: 99%

Effects of ruminally degradable starch levels on performance, nitrogen balance, and nutrient digestibility in dairy cows fed low corn-based starch diets

Luo

Yang

et al. 2016

Asian-Australas J Anim Sci

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ObjectiveThis trial was performed to examine the effects of ruminally degradable starch (RDS) levels in total mixed ration (TMR) with low corn-based starch on the milk production, whole-tract nutrient digestibility and nitrogen balance in dairy cows.MethodsEight multiparous Holstein cows (body weight [BW]: 717±63 kg; days in milk [DIM]: 169±29) were assigned to a crossover design with two dietary treatments: a diet containing 62.3% ruminally degradable starch (% of total starch, low RDS) or 72.1% ruminally degradable starch (% of total starch, high RDS). Changes to the ruminally degradable levels were conducted by using either finely ground corn or steam-flaked corn as the starch component.ResultsThe results showed that dry matter intake, milk yield and composition in dairy cows were not affected by dietary treatments. The concentration of milk urea nitrogen was lower for cows fed high RDS TMR than low RDS TMR. The whole-tract apparent digestibility of neutral detergent fiber, acid detergent fiber and crude protein decreased, and that of starch increased for cows fed high RDS TMR over those fed low RDS TMR, with no dietary effect on the whole-tract apparent digestibility of dry matter and organic matter. The proportion of urinary N excretion in N intake was lower and that of fecal N excretion in N intake was higher for cows fed high RDS TMR than those fed low RDS TMR. The N secretion in milk and the retention of N were not influenced by the dietary treatments. Total purine derivative was similar in cows fed high RDS TMR and low RDS TMR. Consequently, estimated microbial N flow to the duodenum was similar in cows fed high RDS TMR and low RDS TMR.ConclusionResults of this study show that ruminally degradable starch levels can influence whole-tract nutrient digestibility and nitrogen balance in dairy cows fed low corn-based starch diets, with no influence on performance.

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The effect of processing on digestion and utilization of cereals by ruminants

Cited by 50 publications

References 26 publications

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

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

Effect of formaldehyde-treated barley or escape protein on nutrient digestibility, growth and carcass traits of feedlot lambs

Effects of ruminally degradable starch levels on performance, nitrogen balance, and nutrient digestibility in dairy cows fed low corn-based starch diets

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