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Short-chain fatty acid content and pH in caecum of rats given various sources of carbohydrates

Berggren, Anna ; Björck, Inger LU ; Nyman, Margareta LU and Eggum, Bjørn O. (1993) In Journal of the Science of Food and Agriculture 63(4). p.397-406
Abstract

The caecal content of short‐chain fatty acids (SCFA; acetic, propionic and butyric acid), caecal pH, fermentability and dry matter digestibility (DMD) were examined through balance experiments in rats fed 11 various indigestible carbohydrates. The following carbohydrate sources were incorporated into test diets: cellulose, oat husk, wheat bran, oat bran, pea fibre, linseed fibre, low methoxylated (LM)‐pectin, guargum, β‐glucans, neosugar and raffinose. The indigestible carbohydrates, except for those in wheat bran, oat husk and cellulose, were highly fermented, ie > 90%. Caecal pH varied between 5·6 and 7·8, with neosugar and raffinose causing the lowest pH and the fibre‐free diet and the diet with oat husk the highest. The caecal... (More)

The caecal content of short‐chain fatty acids (SCFA; acetic, propionic and butyric acid), caecal pH, fermentability and dry matter digestibility (DMD) were examined through balance experiments in rats fed 11 various indigestible carbohydrates. The following carbohydrate sources were incorporated into test diets: cellulose, oat husk, wheat bran, oat bran, pea fibre, linseed fibre, low methoxylated (LM)‐pectin, guargum, β‐glucans, neosugar and raffinose. The indigestible carbohydrates, except for those in wheat bran, oat husk and cellulose, were highly fermented, ie > 90%. Caecal pH varied between 5·6 and 7·8, with neosugar and raffinose causing the lowest pH and the fibre‐free diet and the diet with oat husk the highest. The caecal pool sizes of SCFA were highest with raffinose, β‐glucans, LM‐pectin, guargum and linseed fibre (335‐400 μmol) while pea fibre, wheat bran, oat bran and neosugar gave intermediate levels (137–227 μmol). The pool size with oat husk and cellulose was similar as with the basal diet (45–64 μmol). A high proportion of propionic acid was obtained with guargum and linseed fibre, whereas acetic acid was the predominant product in case of LM‐pectin. On the other hand, linseed fibre gave a remarkably low proportion of butyric acid. The quantity fermented and caecal pH correlated well to the amount of SCFA with most materials (r = 0·96 and r = −0·87, respectively), an exception was neosugar and in case of fermentability also oat bran. DMD values with most of the easily fermented carbohydrates were high (>96%). Exceptions were diets with β‐glucans and oat bran which caused low DMD values, about 93%. It is concluded that indigestible carbohydrates may differ in ability to lower caecal pH and to form SCFA during fermentation.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
caecal pH, dietary fibres, dry matter digestibility, fermentation, oligosaccharides, rat experiments, short‐chain fatty acids
in
Journal of the Science of Food and Agriculture
volume
63
issue
4
pages
10 pages
publisher
Wiley-Blackwell
external identifiers
  • scopus:0027135109
ISSN
0022-5142
DOI
10.1002/jsfa.2740630405
language
English
LU publication?
yes
id
5109064d-04b9-40a4-9126-32b861ca94f2
date added to LUP
2018-10-16 19:31:17
date last changed
2023-09-08 09:08:47
@article{5109064d-04b9-40a4-9126-32b861ca94f2,
  abstract     = {{<p>The caecal content of short‐chain fatty acids (SCFA; acetic, propionic and butyric acid), caecal pH, fermentability and dry matter digestibility (DMD) were examined through balance experiments in rats fed 11 various indigestible carbohydrates. The following carbohydrate sources were incorporated into test diets: cellulose, oat husk, wheat bran, oat bran, pea fibre, linseed fibre, low methoxylated (LM)‐pectin, guargum, β‐glucans, neosugar and raffinose. The indigestible carbohydrates, except for those in wheat bran, oat husk and cellulose, were highly fermented, ie &gt; 90%. Caecal pH varied between 5·6 and 7·8, with neosugar and raffinose causing the lowest pH and the fibre‐free diet and the diet with oat husk the highest. The caecal pool sizes of SCFA were highest with raffinose, β‐glucans, LM‐pectin, guargum and linseed fibre (335‐400 μmol) while pea fibre, wheat bran, oat bran and neosugar gave intermediate levels (137–227 μmol). The pool size with oat husk and cellulose was similar as with the basal diet (45–64 μmol). A high proportion of propionic acid was obtained with guargum and linseed fibre, whereas acetic acid was the predominant product in case of LM‐pectin. On the other hand, linseed fibre gave a remarkably low proportion of butyric acid. The quantity fermented and caecal pH correlated well to the amount of SCFA with most materials (r = 0·96 and r = −0·87, respectively), an exception was neosugar and in case of fermentability also oat bran. DMD values with most of the easily fermented carbohydrates were high (&gt;96%). Exceptions were diets with β‐glucans and oat bran which caused low DMD values, about 93%. It is concluded that indigestible carbohydrates may differ in ability to lower caecal pH and to form SCFA during fermentation.</p>}},
  author       = {{Berggren, Anna and Björck, Inger and Nyman, Margareta and Eggum, Bjørn O.}},
  issn         = {{0022-5142}},
  keywords     = {{caecal pH; dietary fibres; dry matter digestibility; fermentation; oligosaccharides; rat experiments; short‐chain fatty acids}},
  language     = {{eng}},
  month        = {{01}},
  number       = {{4}},
  pages        = {{397--406}},
  publisher    = {{Wiley-Blackwell}},
  series       = {{Journal of the Science of Food and Agriculture}},
  title        = {{Short-chain fatty acid content and pH in caecum of rats given various sources  of carbohydrates}},
  url          = {{http://dx.doi.org/10.1002/jsfa.2740630405}},
  doi          = {{10.1002/jsfa.2740630405}},
  volume       = {{63}},
  year         = {{1993}},
}