Livestock Production Science 63 2000 141–152 www.elsevier.com locate livprodsci
Use of digestible fibre in replacement to available carbohydrates
Effect on digestion, rate of passage and caecal fermentation pattern during the growth of the rabbit
Thierry Gidenne , Rachel Bellier
Institut National de la Recherche Agronomique , Station de Recherches Cunicoles, BP 27, 31326 Castanet-Tolosan, France
Received 14 September 1998; received in revised form 20 April 1999; accepted 10 May 1999
Abstract
The dietary replacement of available carbohydrates mainly starch by digestible fibre was assessed on rabbit growth and digestion. Two diets supplying hemicellulose diet HC or a mix of hemicellulose and pectins HC 1 P were compared to a
control diet having a higher starch content, but a similar content in low digested fibre lignocellulose ADF 5 155 g kg. Three groups of 17 rabbits were allocated at weaning 28 d to each diet. Nine animals of each group were cannulated to
follow the caecal microbial activity from 45 to 70 d old. Compared to control, rabbits fed HC or HC 1 P increased feed intake 1 10, but only HC 1 P resulted in a higher weight gain and in a similar feed conversion mean 2.00, particularly
during the postweaning period 4–6 wk old. Transit of liquids was similar among diets, either in the caeco–colic segment or in the whole tract. HC 1 P diet gave short caeco–colic transit for particles 13.1 h, and also the highest caecal SCFA level
62.2 mM l and pool 3.8 mM, while HC and control diet led to similar caecal fermentation mean 5 56.5 and 2.25, respectively for SCFA level and pool. SCFA concentration increased according to the mean intake of ‘‘hemicellulose 1
pectins’’, suggesting that microbial activity and fibre degradation were more affected by the nature of the cell wall than by the caeco–colic retention time.
2000 Elsevier Science B.V. All rights reserved.
Keywords : Rabbit digestion; Caecal fermentation; Starch; Hemicellulose; Pectins; Dietary fibre
1. Introduction hindgut flora and to ensure digestive motility and
transit and metabolic functions of the host Mathers, ´
For monogastric species and particularly for the 1991; Carre, 1992; Edwards and Parrett, 1996.
growing rabbit, supplying dietary fibre corresponds Digestive consequences of fibre are determined as
to two main roles: to provide nutrients for the well by the quantity of dietary fibre consumed as by
the degradability of cell wall components in relation to their physico–chemical structure.
Corresponding author Tel.: 1 33-5-6128-5103; fax: 1 33-5-
Previous studies on growing rabbit have addressed
6128-5319. E-mail address
: gidennetoulouse.inra.fr T. Gidenne
the problem of increasing the intake of low digestible
0301-6226 00 – see front matter
2000 Elsevier Science B.V. All rights reserved. P I I : S 0 3 0 1 - 6 2 2 6 9 9 0 0 1 2 3 - 2
142 T
. Gidenne, R. Bellier Livestock Production Science 63 2000 141 –152 Table 1
fibre to prevent digestive troubles mainly diarrhoea,
Composition of the experimental diets
but associated to a negative effect on growth per-
Diet Control
HC HC 1 P
ˆ formance Ma ı tre et al., 1990. Conversely, dietary
starch could also play a substantial role in interaction
Ingredients g kg diet
with fibre, as it is incompletely hydrolysed in the
Wheat straw 120
150 140
Wheat bran 270
50
small intestine of the weanling rabbit Blas et al.,
Sugar Beet pulp 200
1988; Blas et al., 1994 causing alteration of the
Sunflower meal 250
50 50
caeco–colic digestion associated with digestive dis-
Soya bean meal 35
98 162
turbances.
Wheat 560
400 367
a
Therefore, the reduction of starch supply should
Minerals and vitamins 35
32 31
be explored without excessive reduction in the
Chemical composition g kg DM
digestible energy and without modifying the supply
Organic matter 928
925 924
in low digested fibre fraction. Because the caeco–
Starch 361
290 256
colic fermentation is relatively short 7–12 h; Giden-
Crude protein N 3 6.25 176
167 179
ne, 1997, the use of rapidly fermented fibre i.e.,
Gross Energy MJ kg DM 17.96
18.13 17.87
Water insoluble cell-wall 280
341 338
digestible fibre replacing available carbohydrates
Neutral-detergent fibre 286
339 327
could be of interest to supply energy to the host via
Acid-detergent fibre 149
150 163
caecal microbial activity, without alteration of rate of
Acid-detergent lignin 40
30 27
b
passage. The level of degradation for hemicellulose
Hemicellulose 137
189 164
fractions 30–45 and for pectins 70 in the
Uronic acids 27
18 59
c
Pectins 30
19 82
rabbit classes these cell wall constituents in the
a
‘‘digestible fibre’’ compared to low-digested fibres
Contained: g kg, respectively for C, HC; HC 1 P diets calcium carbonate and bicalcium phosphate 21.0, 17.5, 18.0,
such as lignocellulose Gidenne et al., 1998a. The
DL
-methionine 0.5, 1.5, 1.5,
L
-lysine 1.5, 1.0, 0.0 salt 7.0, 7.0,
present study assessed two ways of starch replace-
6.5; and 5.0 g kg diet of vitamin premix retinol 540 mg kg,
ment either mainly through a supply of hemicellulose
cholecalcipherol 5 mg kg, a-tocopherol 3.3 mg kg, robenidine
or with a mix of hemicellulose and pectins. Further-
13.2 mg kg.
b
more, we aimed to develop a new approach to obtain
Hemicellulose fraction estimated by difference between NDF and ADF.
a more comprehensive information on caecal diges-
c
Water insoluble pectins: calculated from tabulated data on
tion, that included simultaneous in-vivo measure-
ingredients IO7, 1993.
ment of rate of passage, nutrient digestion and caecal microbial activity CMA, over a substantial period
of the rabbit growth 6–10 wk old.
ADF, mainly provided by one source wheat straw
2. Materials and methods to avoid major change in the type of cellulose or
