Book Review

Evans, Frankis T.

doi:10.1093/bja/29.8.357

Cited by 2 publications

(2 citation statements)

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“…During the course of digestion, particles in the rumen become more fragile (Akin, 1979) and hence more easily physically dispersed. Decreasing particle size in the rumen also increases the density of particles (Evans et al 1973) and thus stratification of particles tends to occur (see Evans et a f . 1973), small particles sinking and being passed out of the rumen and larger particles rising and being further subjected to physical breakdown by rumination and prolonged fermentation through increased rumen retention time.…”

Section: Particle Sizementioning

confidence: 99%

Physicochemical characteristics of food and the digestion of starch and dietary fibre during gut transit

1988

Proc. Nutr. Soc.

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Section: Particle Sizementioning

confidence: 99%

Physicochemical characteristics of food and the digestion of starch and dietary fibre during gut transit

1988

Proc. Nutr. Soc.

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“…Alternatively, by considering the rumen contents as a single kinetic pool, Minson (1966) measured a total turnover rate equal to the sum of rate of digestion and rate of outflow, while Faichney (1980) employed an approach that was conceptually similar to estimate the fractional outflow rate (FOR) of constituents from the rumen. However, the latter methods do not take into account the presence in the rumen pool of particles of dimensions that may be too large to pass readily from the rumen (Hungate, 1966;Pearce, 1967;Evans et al 1973). Description of the effect of particle size on passage from the rumen should permit a more complete understanding of the regulation of particulate movement and control of intake.…”

mentioning

confidence: 99%

Removal of digesta components from the rumen of steers determined by sieving techniques and fluid, particulate and microbial markers

Dixon

Milligan

1985

Br J Nutr

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1. When 103Ru-labelled Tris (1,lO-phenanthroline) ruthenium I1 chloride (lo3Ru-P) particulate marker in aqueous solution was added to the rumen of four steers given 5.5 kg grass hay/d at two-hourly intervals, the distribution of lo3Ru-P marker among rumen particles of various sizes was the same at 4 h, 3 d and 7 d after administration, the concentration of ln3Ru-P/g dry matter (DM) was inversely related to particle size and 0.30 of the lo3Ru-P was associated with the DM of particles too large to be moved from the rumen at a meaningful rate. Thus, fractional outflow rate (FOR) of lo3Ru-P would reflect, but was not a direct measure of, the FOR of the small particle pool in the rumen.2. When rumen digesta were labelled with ln3Ru-P, placed in nylon cloth bags and incubated in vitro with unlabelled digesta, 59% of the loaRu-P disappeared from the nylon bag in 24 h, and 74% in 48 h. Similar results were obtained when large particles (retained by a 3.2 mm mesh screen during wet sieving) from rumen digesta were subjected to this procedure.3. In a further experiment, the steers were given the hay in either the long or ground form and drinking water to which 10 g sodium chloride/l were, or were not, added.4. The FOR of WrEDTA in centrifuged rumen fluid was increased (P i 0.05) from 1.78 to 2.10/d by grinding of the hay diet, but was not influenced by the intake of an additional 257 g NaCl/d. The FOR values of lo3Ru-P in mixed rumen digesta and organic 35S in micro-organisms were linearly correlated (P < 0.05) and were not affected (P > 0.05) by grinding and salt treatments. On average, the FOR of organic 35S in micro-organisms was 0.41 of that of WrEDTA in centrifuged rumen fluid and 0.85 of that of ln3Ru-P in rumen digesta respectively. 5.Grinding of the hay did not (P > 0.05) change the proportion of rumen DM (0.47W.515) or faecal DM (0.107-0.153) retained by the 3.2 mm mesh and larger screens.6. FOR from the rumen of a given size group of particles was calculated as the ratio, estimated daily flow from the rumen of the size group: rumen pool of the group. With increasing particle size there was a progressive decline in FOR; values of FOR for groups of particles greater than 4.0 mm were negligible. If the rumen DM was considered to behave as two pools, the 3.2 mm mesh screen appeared to be an appropriate division between the large-particle and the small-particle DM pools.7. FOR of lignin present in mixed rumen digesta was 0.48 of the mean of the FOR values of the particle groups of the small-particle pool, while the FOR of lignin present in the small-particle pool was 0.92 of the mean small-particle FOR.

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Book Review

Cited by 2 publications

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Physicochemical characteristics of food and the digestion of starch and dietary fibre during gut transit

Physicochemical characteristics of food and the digestion of starch and dietary fibre during gut transit

Removal of digesta components from the rumen of steers determined by sieving techniques and fluid, particulate and microbial markers

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